Publications by authors named "Schingoethe D"

103 Publications

Feeding lactose to increase ruminal butyrate and the metabolic status of transition dairy cows.

J Dairy Sci 2006 Jan;89(1):267-76

Dairy Science Department, South Dakota State University, Brookings, 57007, USA.

Twenty-four multiparous Holstein cows (775 +/- 24 kg body weight; 3.4 +/- 0.11 body condition score) were used in a randomized complete block design experiment to determine the impact of increased ruminal butyrate from the fermentation of lactose on metabolism and lactation. Dietary treatments were either a corn-based control diet (CON) or a diet containing lactose at 15.7% of diet dry matter (LAC). Experimental diets were fed from 21 d before expected calving through 21 d in milk (DIM). Blood was sampled at -21, -14, -7, -2, 2, 7, 14, and 21 DIM, rumen fluid at -21, -7, and 7 DIM, and liver tissue via biopsy at 7 and 14 DIM. Pre- and postpartum dry matter intake (DMI) through 28 DIM averaged 12.8 and 17.7 kg/d, respectively, and did not differ between treatments; however, cows fed LAC did not exhibit a prepartum decrease in DMI. Milk yield was unaffected by treatments and averaged 45.7 kg/d during the first 70 DIM. Plasma glucose, insulin, and non-esterified fatty acids were not affected by dietary treatments. Feeding LAC increased the ruminal proportion of butyrate both pre- (11.3 vs. 9.2 +/- 0.45%) and postpartum (13.0 vs. 10.3 +/- 0.67%). Likewise, circulating plasma beta-hydroxybutyrate was increased both pre- (6.1 vs. 4.2 +/- 0.31 mg/dL) and postpartum (14.6 vs. 8.34 +/- 1.7 mg/dL) when feeding LAC compared with CON. Liver lipid content was decreased (8.6. vs. 14.7 +/- 1.5% of wet weight) in cows fed LAC relative to those fed CON, whereas liver glycogen was not affected by dietary treatments. Feeding lactose to transition dairy cows increased the proportion of butyrate in the rumen and beta-hydroxybutyrate in plasma and decreased liver lipid but did not affect lactation performance.
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http://dx.doi.org/10.3168/jds.S0022-0302(06)72091-4DOI Listing
January 2006

Lactational response of cows fed condensed corn distillers solubles.

J Dairy Sci 2005 Nov;88(11):4000-6

Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.

Fifteen Holstein cows (6 multiparous and 9 primiparous) in early lactation were used in a replicated 3 x 3 Latin square design with 5-wk periods to evaluate the use of condensed corn distillers solubles (CCDS) in the total mixed ration. Diets were control (0%), low (5%), or high (10% of dry matter) CCDS. All diets contained alfalfa hay, corn silage, rolled corn, and a concentrate supplement formulated to yield isonitrogenous diets. Condensed corn distillers solubles replaced a portion of the rolled corn and soybean meal in the control diet. Data were collected from wk 3 to 5 of each 5-wk period. Dry matter intakes (23.4, 24.4, and 22.5 kg/d for control, low, and high CCDS, respectively) were similar for CCDS and control and tended to be greater for low than for high CCDS. Milk yields (34.1, 35.5, and 35.8 kg/d) were greater for added CCDS vs. control, with no additional benefit found by feeding a high over a low amount of CCDS. Milk fat percentage decreased slightly, whereas protein and lactose production increased when cows were fed CCDS. Medium-chain fatty acids in milk fat were decreased and long-chain fatty acids increased by feeding CCDS, and similar changes were found comparing high with low level of CCDS. Unsaturated fatty acids in milk fat tended to be higher for diets containing CCDS compared with control and were higher for high compared with low inclusion. Ruminal ammonia and serum urea nitrogen concentrations were lower when cows were fed CCDS. This study indicated that it is advantageous to feed CCDS at 5% of dry matter; however, some beneficial changes in milk fatty acid composition were achieved by doubling that amount.
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http://dx.doi.org/10.3168/jds.S0022-0302(05)73086-1DOI Listing
November 2005

Feed efficiency of mid-lactation dairy cows fed yeast culture during summer.

J Dairy Sci 2004 Dec;87(12):4178-81

Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.

Thirty-eight Holstein cows (26 multiparous and 12 primiparous), that averaged 105 d postpartum at the start of the experiment, were used to evaluate the feeding of yeast culture (60 g/cow daily of Diamond V XP) on production efficiency during hot summer weather. From early June until early September and after a 2-wk covariate period, cows were fed a control diet without or with 60 g of yeast culture/cow daily for 12 wk. Weekly daytime high temperatures in the free-stall barn during the 12-wk period averaged 33 degrees C (28 to 39 degrees C). Total mixed diets on a dry matter (DM) basis consisted of corn silage (28%), alfalfa hay (21%), and a concentrate mix (51%) without or with the yeast culture added to the total mixed ration at the time of feeding. Milk production (34.9 and 35.4 kg/d, for control and yeast culture treatment, respectively), 4% fat-corrected milk (31.2 and 32.0 kg/d), energy-corrected milk (ECM; 33.4 and 34.2 kg/d), and DM intake (23.1 and 22.1 kg/d) were similar for cows fed control and yeast culture diets. Percentages of milk fat (3.34 and 3.41) and true protein (2.85 and 2.87) were similar for both diets. Feed efficiency defined as kilogram of ECM/kilogram of DM intake was improved by 7% for cows fed the yeast culture. Body weights and body condition scores were similar for both groups. The results suggest that the yeast culture can improve feed efficiency of heat stressed dairy cows in midlactation.
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http://dx.doi.org/10.3168/jds.S0022-0302(04)73561-4DOI Listing
December 2004

The energy content of wet corn distillers grains for lactating dairy cows.

J Dairy Sci 2004 Jun;87(6):1815-9

Department of Animal and Range Sciences, South Dakota State University, Brookings 57007-0647, USA.

Forty-five energy balances were completed with 12 multiparous, lactating Holstein cows in a study designed to determine the energy content of wet corn distillers grains. Treatments were applied in a repeated switchback design and consisted of total mixed diets containing 31.4% corn silage, 18.4% alfalfa hay, and either 30.7% rolled corn and 16.7% soybean meal or 17.0% rolled corn and 31.2% wet corn distillers grains (dry matter basis). Replacement of corn and soybean meal with wet corn distillers grains reduced dry matter intake 10.9% but did not affect milk production. Neither digestible nor metabolizable energy were affected by diet composition. Heat and milk energy output did not differ by diet, but body energy retained was 2.8 Mcal/d less in cows fed the wet corn distillers grains diet. Multiple regression estimates of maintenance metabolizable energy requirement and partial efficiencies of metabolizable energy used for lactation and body energy deposition did not differ by diet. Pooled estimates were 136.2, 0.66, and 0.85, kcal of metabolizable energy/ body weight0.75 per day, respectively. Calculated by difference, wet corn distillers grains was estimated to contain 4.09, 3.36, and 2.27 Mcal/kg of dry matter as digestible, metabolizable, and lactational net energy, respectively. These energy estimates were 7 to 11% and 10 to 15%, respectively, greater than those reported for dried corn distillers grains by the 1989 and 2001 dairy NRC publications.
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http://dx.doi.org/10.3168/jds.S0022-0302(04)73338-XDOI Listing
June 2004

Conjugated linoleic acid increases in milk when cows fed fish meal and extruded soybeans for an extended period of time.

J Dairy Sci 2004 Jun;87(6):1758-66

Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.

The objective of this study was to determine the effect of feeding a conjugated linoleic acid (CLA) stimulating diet for an extended period of time on milk cis-9, trans-11 CLA and vaccenic acid (VA) concentrations. Twenty cows (16 Holstein and 4 Brown Swiss) were divided into 2 groups (n = 10 per treatment) for a 10-wk study. Cows in group 1 were fed a traditional corn-soybean-basal diet (control), while those in group 2 were fed a blend of 0.5% fish oil from fish meal and 2% soybean oil from extruded soybeans (FMESB) to achieve higher milk fat cis-9, trans-11 CLA and VA. Diets were formulated to contain 18% CP and were composed (dry matter basis) of 50% concentrate mix, 25% corn silage, and 25% alfalfa hay. Dry matter intake was not affected by diet. Milk production increased in cows fed the FMESB diet. Milk fat and milk protein percentages decreased with the FMESB diet; however, milk fat and protein yields were not affected by treatments. Milk fat cis-9, trans-11 CLA and VA concentration (g/100 of fatty acids) and yield (g/d) were 2.5-fold greater for cows fed the FMESB diet over the 10 wk of fat supplementation. For cows fed the FMESB diet, contents of milk fat cis-9, trans-11 CLA and VA gradually increased from the first week of fat supplementation, reached the highest concentrations in wk 3, then gradually decreased during wk 4 and 5 and then remained relatively constant until wk 10. The concentration of cis-9, trans-11 CLA and VA from the control diet was relatively constant over the 10 wk of fat supplementation. Concentrations of cis-9, trans-11 CLA and VA in milk fat can be increased within a week by feeding a blend of fish meal and extruded soybeans, and that increase remains relatively constant after wk 5 of fat supplementation.
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http://dx.doi.org/10.3168/jds.S0022-0302(04)73331-7DOI Listing
June 2004

Feeding lactose increases ruminal butyrate and plasma beta-hydroxybutyrate in lactating dairy cows.

J Dairy Sci 2004 Aug;87(8):2486-94

Dairy Science Department, South Dakota State University, Brookings 57007, USA.

Ruminal fermentation of lactose increases molar proportions of butyrate, which is metabolized by the ruminal epithelium to beta-hydroxybutyrate (BHBA). To determine the effects of dietary whey, and specifically lactose, on concentrations of ruminal and blood volatile fatty acids (VFA) and blood BHBA, 8 Holstein and 4 Brown Swiss multiparous cows (210 +/- 33 d in milk) were blocked by breed and randomly assigned to one of three 4 x 4 Latin squares. Treatments were control (CON; 7.1% of dietary dry matter [DM] as cornstarch), liquid whey (WHEY; 9.4% of diet DM) containing 70% lactose on a DM basis, low lactose (LOLAC; 7.1% lactose), or high lactose (HILAC; 14.3% lactose). Diets contained 53% forage as corn silage, alfalfa hay, and grass hay (DM basis) and a corn and soybean meal-based concentrate. Average dietary percentage of crude protein and energy density (Mcal/kg net energy for lactation) were 16.8 and 1.47, respectively. Feeding lactose increased DM intake. Milk production and composition were not affected by diet with the exception of decreased urea nitrogen in milk from cows fed lactose. Greater proportions of ruminal propionate were observed in cows fed CON relative to those fed WHEY and LOLAC. Increasing dietary lactose increased proportions of ruminal butyrate and decreased acetate and branched-chain VFA. Concurrent with the increase in ruminal butyrate concentrations, there was an increase in plasma BHBA as lactose in the diet increased. Concentrations of VFA in plasma were not affected by diet with the exception of the branched-chain VFA, which were increased in cows fed LOLAC compared with WHEY. These data indicate lactose fermentation increases proportions of ruminal butyrate and plasma BHBA in lactating dairy cows; however, the observed increase in plasma BHBA is not sufficient to subject cows to ketosis.
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http://dx.doi.org/10.3168/jds.S0022-0302(04)73373-1DOI Listing
August 2004

Conjugated linoleic acid and vaccenic acid in rumen, plasma, and milk of cows fed fish oil and fats differing in saturation of 18 carbon fatty acids.

J Dairy Sci 2003 Nov;86(11):3648-60

Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.

The objective of this study was to examine the effect of feeding fish oil (FO) along with fat sources that varied in saturation of 18 carbon fatty acids (high stearic, high oleic, high linoleic, or high linolenic acids) on rumen, plasma, and milk fatty acid profiles. Four primiparous Holstein cows at 85 d in milk (+/- 40) were assigned to 4 x 4 Latin squares with 4-wk periods. Treatment diets were 1) 1% FO plus 2% commercial fat high in stearic acid (HS); 2) 1% FO plus 2% fat from high oleic acid sunflower seeds (HO); 3) 1% FO plus 2% fat from high linoleic acid sunflower seeds (HLO); and 4) 1% FO plus 2% fat from flax seeds (high linolenic; HLN). Diets were formulated to contain 18% crude protein and were composed of 50% (dry basis) concentrate mix, 25% corn silage, 12.5% alfalfa silage, and 12.5% alfalfa hay. Milk production, milk protein percentages and yields, and dry matter intake were similar across diets. Milk fat concentrations and yields were least for HO and HLO diets. The proportion of milk cis-9, trans-11 conjugated linoleic acid (CLA; 0.71, 0.99, 1.71, and 1.12 g/100 g fatty acids, respectively), and vaccenic acid (TVA; 1.85, 2.60, 4.14, and 2.16 g/100 g fatty acids, respectively) were greatest with the HLO diet. The proportions of ruminal cis-9, trans-11 CLA (0.09, 0.16, 0.18, and 0.16 g/100 g fatty acids, respectively) were similar for the HO, HLO, and HLN diets and all were higher than for the HS diet. The proportions of TVA (2.85, 4.36, 8.69, and 4.64 g/100 g fatty acids, respectively) increased with the HO, HLO, and HLN diets compared with the HS diets, and the increase was greatest with the HLO diet. The effects of fat supplements on ruminal TVA concentrations were also reflected in plasma triglycerides, (2.75, 4.64, 8.77, and 5.42 g/100 g fatty acids, respectively); however, there were no differences in the proportion of cis-9, trans-11 CLA (0.06, 0.07, 0.06, and 0.07 g/100 g fatty acids, respectively). This study further supports the significant role for mammary delta-9 desaturase in milk cis-9, trans-11 CLA production.
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http://dx.doi.org/10.3168/jds.S0022-0302(03)73970-8DOI Listing
November 2003

Milk production and composition from cows fed high oil or conventional corn at two forage concentrations.

J Dairy Sci 2003 Jul;86(7):2428-37

Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.

Twelve multiparous Holstein cows (63 +/- 24 d in milk) were used in a replicated 4 x 4 Latin square with 28-d periods to evaluate conventional and high oil corn grains when fed at two different forage-to-concentrate ratios. Dietary treatments consisted of conventional or high oil corn supplementing a diet with a 25:25:50 mixture of corn silage: alfalfa: concentrate mix, or a high forage diet with a 30:30:40 mixture of corn silage: alfalfa: concentrate mix. Dry matter intake (28.1, 28.7, 26.9, and 26.2 kg/d for normal diets with conventional and high oil corn, and high forage diets with conventional and high oil corn, respectively) and milk yields (36.8, 37.2, 35.5, and 35.2 kg/d) were similar for conventional and high oil corn diets and were lower with the high forage diet, regardless of corn source. Milk fat concentrations were greater when cows were fed diets containing 60% forage (4.03 vs. 3.88%, for the 60 and 50% forages, respectively), but milk protein concentrations were not affected by forage content. Corn source did not affect milk fat or protein concentrations. Long-chain fatty acid concentrations, unsaturated fatty acid concentrations, and total 18:1 fatty acid concentrations were greater when cows were fed high oil corn but were unaffected by forage content of the diet. Concentrations of transvaccenic acid (0.58, 0.81, 0.62, and 0.69 g/100 g of fatty acids) and cis-9, trans-11 conjugated linoleic acid (0.28, 0.39, 0.32, and 0.33 g/100 g of fatty acids) were greater when cows were fed high oil compared with conventional corn when fed 50% forage but were similar for both corn sources at 60% forage. Total n-3 fatty acids were not affected by corn source or forage content. High forage diets decreased milk production and increased milk fat concentration. Feeding high oil corn increased concentrations of long-chain, unsaturated, transvaccenic, and conjugated linoleic fatty acids in milk; however, production of transvaccenic and conjugated linoleic acids were attenuated by high forage diet.
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http://dx.doi.org/10.3168/jds.S0022-0302(03)73837-5DOI Listing
July 2003

Milk conjugated linoleic acid response to fish oil supplementation of diets differing in fatty acid profiles.

J Dairy Sci 2003 Mar;86(3):944-53

Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.

The objective of this experiment was to examine the effect of feeding fish oil (FO) along with fat sources that varied in their fatty acid compositions (high stearic, high oleic, high linoleic, or high linolenic acids) to determine which combination would lead to maximum conjugated linoleic acid (cis-9,trans-11 CLA) and transvaccenic acid (TVA) concentrations in milk fat. Twelve Holstein cows (eight multiparous and four primiparous cows) at 73 (+/- 32) DIM were used in a 4 x 4 Latin square with 4-wk periods. Treatment diets were 1) 1% FO plus 2% fat source high in stearic acid (HS), 2) 1% FO plus 2% fat from high oleic acid sunflower seeds (HO), 3) 1% FO plus 2% fat from high linoleic acid sunflower seeds (HLO), and 4) 1% FO plus 2% fat from flax seeds (high linolenic; HLN). Diets formulated to contain 18% crude protein were composed of 50% (dry basis) concentrate mix, 25% corn silage, 12.5% alfalfa haylage, and 12.5% alfalfa hay. Milk production (35.8, 36.3, 34.9, and 35.0 kg/d for diets 1 to 4) was similar for all diets. Milk fat percentages (3.14, 2.81, 2.66, and 3.08) and yields (1.13, 1.02, 0.93, and 1.08 kg/d) for diets 1 to 4 were lowest for HLO. Milk protein percentages (3.04, 3.03, 3.10, and 3.08) and dry matter intake (DMI) (25.8, 26.0, 26.2, and 26.2 kg/d) for diets 1 to 4 were similar for all diets. Milk cis-9,trans-11 CLA concentrations (0.70, 1.04, 1.70, and 1.06 g/100 g fatty acids) for diet 1 to 4 and yields (7.7, 10.7, 15.8, and 11.3 g/d) for diets 1 to 4 were greatest with HLO and were least with HS. Milk cis-9,trans-11 CLA concentrations and yields were similar for cows fed the HO and the HLN diets. Similar to milk cis-9,trans-11 CLA, milk TVA concentration (1.64, 2.49, 3.74, and 2.41 g/100 g fatty acids) for diets 1 to 4 was greatest with the HLO diet and least with the HS diet. Feeding a high linoleic acid fat source with fish oil most effectively increased concentrations and yields of milk cis-9,trans-11 CLA and TVA.
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http://dx.doi.org/10.3168/jds.S0022-0302(03)73677-7DOI Listing
March 2003

Fatty acid profiles of milk and rumen digesta from cows fed fish oil, extruded soybeans or their blend.

J Dairy Sci 2002 Sep;85(9):2266-76

Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.

Four fistulated primiparous cows (two Holstein and two Brown Swiss) averaging 102 DIM were used in a 4 x 4 Latin square with 3-wk periods to determine the effect of feeding fish oil, extruded soybeans, or their combination on fatty acid profiles of milk and rumen digesta. Experimental diets consisted of: 1) control diet; 2) a diet with 2% (DM basis) added fat from menhaden fish oil; 3) a diet with 2% added fat from extruded soybeans; and 4) a diet with 1% added fat from fish oil and 1% fat from extruded soybeans. All diets consisted of 25% corn silage, 25% alfalfa hay, and 50% concentrate. Milk yields (28.6, 29.7, 29.2, and 28.1 kg/d for control, fish oil, extruded soybeans, and combination diets, respectively) were similar for all fat supplements and control. Milk fat and protein percentages (3.49, 3.08; 3.25, 2.96; 3.47, 3.01; 3.48, 2.99 for diets 1, 2, 3, and 4, respectively) were not affected by fat supplements compared with control. Dry matter intake (23.0, 21.6, 22.7, and 21.6 kg/d) was reduced when diets containing fish oil were fed. Concentrations of conjugated linoleic acid [CLA; cis-9, trans-11 CLA, 0.40, 0.88, 0.87, and 0.80 g/100 g fatty acids (FA)] and transvaccenic acid (TVA, 1.02, 2.34, 2.41, and 2.06 g/100 g of FA) were increased in milk fat by all fat supplements, with no differences in milk CLA and TVA observed among fat supplements. As with milk fat, proportions of ruminal CLA (0.09, 0.26, 0.18, and 0.21 g/100 g of FA) and TVA (2.61, 4.56, 4.61, and 4.39 g/100 g of FA) increased with fat supplements. The effects of fat supplements on ruminal TVA and CLA concentrations were also reflected in rumen FA-salts, free fatty acids, and neutral lipids. The higher TVA to CLA ratio in the rumen compared with milk indicated that fat supplements increased milk CLA concentration mainly by increasing ruminal production of TVA, which also implied the significant role that mammary delta-9 desaturase plays in milk CLA concentrations.
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http://dx.doi.org/10.3168/jds.S0022-0302(02)74306-3DOI Listing
September 2002

Feeding fish meal and extruded soybeans enhances the conjugated linoleic acid (CLA) content of milk.

J Dairy Sci 2002 Mar;85(3):624-31

Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.

Twelve multiparous Holstein cows averaging 65 (33 to 122) DIM were used in a 4 x 4 Latin square for 4-wk periods to determine whether feeding fish oil as fish meal would stimulate increased amounts of milk conjugated linoleic acid (cis-9, trans-11 C18:2; CLA) and transvaccenic acid (trans-11 C18:1; TVA) when the cows were fed extruded soybeans to supply additional linoleic acid. Treatment diets were 1) control; 2) 0.5% fish oil from fish meal; 3) 2.5% soybean oil from extruded soybeans; and 4) 0.5% fish oil from fish meal and 2% soybean oil from extruded soybeans. Diets were formulated to contain 18% crude protein and were composed (dry basis) of 50% concentrate mix, 25% corn silage, and 25% alfalfa hay. Intake of DM was not affected by diet. Milk production was increased by diets 2, 3, and 4 compared with diet 1 (control). Milk fat and milk protein percentages decreased with diets 3 and 4. Milk fat yield was not affected by treatments, but yield of milk protein was increased with supplemental fish meal and extruded soybeans or their blend. When diets 2, 3, or 4 were fed, concentrations of cis-9, trans-11 CLA in milk fat increased by 0.4-, 1.4-, and 3.2-fold, and TVA concentrations in milk fat increased by 0.4-, 1.8-, and 3.5-fold compared with the control milk fat. Increases in TVA and cis-9, trans-11 CLA were 91 to 109% greater when a blend of fish meal and extruded soybeans was fed than the additive effect of fish meal and extruded soybeans. This suggested that fish oil increased the production of CLA and TVA from other dietary sources of linoleic acid such as extruded soybeans.
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http://dx.doi.org/10.3168/jds.S0022-0302(02)74116-7DOI Listing
March 2002

Fish oil and extruded soybeans fed in combination increase conjugated linoleic acids in milk of dairy cows more than when fed separately.

J Dairy Sci 2002 Jan;85(1):234-43

Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.

Eight multiparous Holstein and four multiparous Brown Swiss (78 +/- 43 DIM) cows were used in a 4 x 4 Latin square with 28-d periods to evaluate if feeding fish oil with a source of linoleic acid (extruded soybeans) would stimulate additional amounts of conjugated linoleic acid in milk. Four treatments consisted of a control diet with a 50:50 ratio of forage to concentrate (DM basis), a control diet with 2% added fat from either menhaden fish oil or extruded soybeans, or a combination of fish oil and extruded soybeans each adding 1% fat. DM intake (24.3, 21.6, 24.5, and 22.5 kg/d, for control, fish oil, extruded soybeans, and combination diets, respectively), milk production (32.1, 29.1,34.6, and 31.1 kg/d), and milk fat content (3.51, 2.79, 3.27, and 3.14%) were lower for cows that consumed either fish oil-containing diet, especially the 2% fish oil diet. The proportion of n-3 fatty acids in milk fat increased similarly among all three fat-supplemented diets. Concentrations of transvaccenic acid (1.00, 4.16, 2.17, and 3.51 g/100 g of fatty acids) and cis-9, trans-11 conjugated linoleic acid (0.60, 2.03, 1.16, and 1.82 g/100 g of fatty acids) in milk fat increased more with fish oil than with extruded soybeans. When fed the combination diet, these fatty acids were approximately 50% higher than expected for Holsteins, whereas concentrations were similar for Brown Swiss compared with feeding each fat source separately. These data indicated that fish oil modifies ruminal or systemic functions, stimulating increased conversion of linoleic acid into transvaccenic and conjugated linoleic acids.
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http://dx.doi.org/10.3168/jds.S0022-0302(02)74072-1DOI Listing
January 2002

Composition and flavor of milk and butter from cows fed fish oil, extruded soybeans, or their combination.

J Dairy Sci 2001 Oct;84(10):2144-51

Minnesota-South Dakota Dairy Foods Research Center, Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.

Milk was collected from eight multiparous Holstein and four multiparous Brown Swiss cows that were distributed into four groups and arranged in a randomized complete block design with four 4-wk periods. The four treatments included a control diet of a 50:50 ratio of forage-to-concentrate; a fish oil diet of the control diet with 2% (on dry matter basis) added fat from menhaden fish oil; a fish oil with extruded soybean diet of the control diet with 1% (on dry matter basis) added fat from menhaden fish oil and 1% (on dry matter basis) added fat from extruded soybeans; and an extruded soybean diet of the control diet with 2% (on dry matter basis) added fat from extruded soybeans. Milk from cows fed control, fish oil, fish oil with extruded soybean, and extruded soybean diets contained 3.31, 2.58, 2.94, and 3.47% fat, respectively. Concentrations of conjugated linoleic acid in milk were highest in the fish oil (2.30 g/100 g of fatty acids) and fish oil with extruded soybean (2.17 g/100 g of fatty acids) diets compared with the control (0.56 g/100 g fatty acids) diet. Milk, cream, butter, and buttermilk from the fish oil, fish oil with extruded soybean, and extruded soybean diets had higher concentrations of transvaccenic acid and unsaturated fatty acids compared with the controls. Butter made from the extruded soybean diet was softest compared with all treatments. An experienced sensory panel found no flavor differences in milks or butters.
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http://dx.doi.org/10.3168/jds.S0022-0302(01)74659-0DOI Listing
October 2001

Conjugated linoleic acid and other beneficial fatty acids in milk fat from cows fed soybean meal, fish meal, or both.

J Dairy Sci 2001 Aug;84(8):1845-50

Dairy Science Department, South Dakota State University, Brookings, 57007-0647, USA.

Twelve multiparous Holstein cows at 48 +/- 8 DIM were used in a 4 x 4 Latin square with 21-d periods to determine the effect of replacing soybean meal with fish meal on feed intake, milk yield, and milk composition. Fish meal substituted for soybean meal on an isonitrogenous basis at 0, 25, 50, and 100% of supplemental protein. Total mixed diets were (DM basis) 25% corn silage, 25% alfalfa hay, and 50% concentrate mix. Intake of DM (27.9, 27.8, 26.1, and 25.8 kg/d for diets 1 to 4, respectively) was similar for all diets. Milk yield (37.5, 37.8, 37.2, and 37.7 kg/d) was not affected by diets. Milk protein percentages (3.23, 3.24, 3.31, and 3.35) increased with 100% fish meal supplementation and tended to be higher with 50% fish meal supplementation compared with 100% soybean meal diet. Milk fat percentages (3.18, 2.99, 3.04, and 2.87) and yield were lower with the 100% fish meal than with the 100% soybean meal diet. Concentration of n-3 fatty acids in milk fat (0.54, 0.56, 0.63, and 0.72 g/100 g fatty acids) increased as the proportion of fish meal in the diet increased. Concentrations of c9,t11 conjugated linoleic acid (CLA; 0.39, 0.44, 0.46, and 0.72 g/100 g fatty acids) and transvaccenic acid (TVA; 1.09, 1.19, 1.28, and 1.54 g/100 g of fatty acids) were higher with the 100% fish meal diet than with the 100% soybean meal diet. A total replacement of soybean meal with fish meal in the diet of lactating cows increased milk protein percentages and the beneficial fatty acids (CLA, TVA, and n-3 FA) in milk fat.
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http://dx.doi.org/10.3168/jds.S0022-0302(01)74624-3DOI Listing
August 2001

Short communication: Consumer evaluation of milk high in conjugated linoleic acid.

J Dairy Sci 2001 Jul;84(7):1607-9

Minnesota-South Dakota Dairy Foods Research Center, Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.

A consumer evaluation was undertaken to determine whether there were differences in the acceptability of milk from cows fed a control or a fish oil diet. The two treatments included a control diet of a 50:50 ratio of forage-to-concentrate and fish oil added to the control diet with 2% (on dry matter basis) added fat from menhaden fish oil. Milk from cows fed the control or fish oil diet contained 3.31 and 2.58% fat and 0.56 and 2.30 g of total conjugated linoleic acid/100 g of fatty acids, respectively. Consumer evaluation of control and fish oil milks found no difference in acceptability.
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July 2001

Blood amino acids and milk composition from cows fed soybean meal, fish meal, or both.

J Dairy Sci 2001 May;84(5):1174-81

Dairy Science Department, South Dakota State University, Brookings, 57007-0647, USA.

Twelve multiparous Holstein cows at 48 +/- 8 d in milk were used in a 4 x 4 Latin square with 21-d periods to determine the effect on feed intake, milk yield, milk composition, and blood amino acids when soybean meal was replaced with fish meal. Fish meal substituted for soybean meal on an isonitrogenous basis at 0, 25, 50, and 100% of supplemental protein. Total mixed diets were (dry matter basis) 25% corn silage, 25% alfalfa hay, and 50% concentrate mix. Intake of dry matter (27.9, 27.8, 26.1, and 25.8 kg/d for diets 1 to 4, respectively) was similar for all diets. Milk yield (37.5, 37.8, 37.2, and 37.7 kg/d) was not affected by diets. Milk protein percentages (3.23, 3.24, 3.31, and 3.35) increased with 100% fish meal supplementation and tended to be higher, with 50% fish meal supplementation compared with 100% soybean meal diet. Milk fat percentages (3.18, 2.99, 3.04, and 2.87) and yields were lower with the 100% fish meal than with the 100% soybean meal diet. Molar proportions of ruminal volatile fatty acids and ammonia were not greatly affected by diet. Fish meal supplementation slightly improved Met status, as shown when blood amino acid data were evaluated. Both extraction efficiency and transfer efficiency of amino acids from the blood by the mammary gland indicated that Met, Lys, and Phe were the most limiting amino acids in all diets. Replacing as much as 50 or 100% of dietary soybean meal with fish meal may improve the amino acid balance and increase the protein content in milk; however, feeding 100% fish meal will likely decrease milk fat percentages.
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May 2001

Composition and properties of milk and butter from cows fed fish oil.

J Dairy Sci 2001 Feb;84(2):345-53

Minnesota-South Dakota Dairy Foods Research Center, Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.

A control diet and a fish oil diet were fed to 12 multiparous Holstein cows to determine how the incorporation of Menhaden fish oil in the diet would influence the fatty acid composition, especially the conjugated linoleic acid and transvaccenic acid, contents of milk and butter. The control diet consisted of a 50:50 ratio of forage to concentrate, and the fish oil diet consisted of the control diet with 2% (on a dry matter basis) added fish oil. Milk from cows fed the control diet contained higher average concentrations of milk fat (3.37%) compared with milk from cows fed the fish oil diet (2.29%). Milk from cows fed fish oil contained higher concentrations of conjugated linoleic acid, transvaccenic acid, and total unsaturated fatty acids (0.68 and 2.51; 1.42 and 6.28; and 30.47 and 41.71 g/100 g of fat, respectively). Butter made from the fish oil diet milk also had higher concentrations of conjugated linoleic acid, transvaccenic acid, and unsaturated fatty acids. Penetrometer readings indicated fish oil diet butters were softer at 4 and 20 degrees C than the control diet butters. Acid degree values were similar in the fish oil butters compared with the control butters. No significant difference was found in the flavor characteristics of milk and butter from cows fed the control and fish oil diets. Production of milk and butter with increased amounts of conjugated linoleic acid, transvaccenic acid, and other beneficial fatty acids may have a desirable impact on the health of consumers and lead to increased sales.
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February 2001

Influence of dietary fish oil on conjugated linoleic acid and other fatty acids in milk fat from lactating dairy cows.

J Dairy Sci 2000 Nov;83(11):2620-8

Dairy Science Department, South Dakota State University, Brookings, 57007-0647, USA.

Lactating cows were fed menhaden fish oil to elevate concentrations of conjugated linoleic acid, transvaccenic acid, and n-3 fatty acids in milk. Twelve multiparous Holstein cows at 48+/-11 DIM were assigned randomly to a replicated 4 x 4 Latin square. Each treatment period was 35 d in length, with data collected d 15 to 35 of each period. On a dry matter (DM) basis, diets contained 25% corn silage, 25% alfalfa hay, and 50% of the respective concentrate mix. Fish oil was supplemented at 0, 1, 2, and 3% of ration DM. Linear decreases were observed for DM intake (28.8, 28.5, 23.4, and 20.4 kg/d) and milk fat (2.99, 2.79, 2.37, and 2.30%) for 0 to 3% dietary fish oil, respectively. Milk yield (31.7, 34.2, 32.3, and 27.4 kg/d) increased as dietary fish oil increased from 0 to 1% but decreased linearly from 1 to 3% dietary fish oil. Milk protein percentages (3.17, 3.19, 3.21, and 3.17) were similar for all treatments. When the 2% fish oil diet was fed, concentrations of conjugated linoleic acid and transvaccenic acid in milk fat increased to 356% (to 2.2 g/ 100 g of total fatty acids) and 502% (to 6.1 g/100 g), respectively, of amounts when 0% fish oil was fed. There were no additional increases in these fatty acids when cows were fed 3% fish oil. The n-3 fatty acids increased from a trace to over 1 g/100 g of milk fatty acids, when the 3% fish oil diet was fed. Fish oil supplementation to diets of dairy cows increased the conjugated linoleic acid, transvaccenic acid, and n-3 fatty acids in milk.
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November 2000

Determination of when during the lactation cycle to start feeding a cellulase and xylanase enzyme mixture to dairy cows.

J Dairy Sci 2000 Oct;83(10):2319-25

Dairy Science Department South Dakota State University Brookings, 57007-0647, USA.

We used 48 multiparous Holstein cows to compare the response of dairy cows to a direct-fed mixture of cellulase and xylanase enzymes (1.25 L of enzyme concentrate/tonne of forage dry matter) applied to the forage portion (60% corn silage and 40% alfalfa hay) of a total mixed diet starting either in the close-up dry period, at calving, or at peak milk production. Cows were blocked by calving date and, within blocks, randomly assigned to one of four treatment diets. Treatments were: 1) an untreated control diet, 2) enzyme addition to the forage from wk 6 to 18 postpartum, 3) enzyme addition to the forage from calving to wk 18 postpartum, and 4) enzyme addition to the forage from wk 4 prepartum to wk 18 postpartum. Total mixed diets were 65% forage and 35% concentrate prepartum, and 50:50 forage:concentrate postpartum. The production of milk, solids-corrected milk, fat-corrected milk, and energy-corrected milk was higher for cows fed enzyme-treated diets than for cows fed control diet. Production was similar for cows in all enzyme-treated groups, although numerically highest for cows that started receiving enzyme-treated forages right after parturition and numerically lowest when started prepartum. Concentrations of fat, protein, and lactose in milk were similar for all treatments; yields of protein and fat were higher for cows fed enzyme-treated forages. Dry matter intake and body condition scores, both prepartum and postpartum, were similar for all diets. Eating rates, as determined in two 24-h studies, were similar for control and enzyme-treated diets. The feeding of enzyme-treated forages increased milk production. While the effect of when the feeding of enzyme-treated forages started was not statistically significant, we recommend starting soon after parturition because of the greatest total milk production when starting at that time.
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http://dx.doi.org/10.3168/jds.s0022-0302(00)75119-8DOI Listing
October 2000

Corn distillers grains versus a blend of protein supplements with or without ruminally protected amino acids for lactating cows.

J Dairy Sci 2000 Sep;83(9):2075-84

Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.

In a replicated 4 x 4 Latin square design with 4-wk periods, we used 12 multiparous Holstein cows averaging 83 d postpartum to compare corn distillers grains (CDG) versus a blend (BLEND) of other protein sources with CDG (fish meal and soybean meal), and to determine the effectiveness of ruminally protected lysine and methionine (RPLM) in improving the utilization of CDG as a protein supplement for lactating cows. The 2 x 2 factorial arrangement of treatments was as follows: CDG diet, CDG diet plus RPLM, BLEND diet, and BLEND diet plus RPLM. All diets contained 30% corn silage, 20% alfalfa hay, and 50% the respective corn-based concentrate mixture. The array of amino acids available for absorption when cows were fed the BLEND diet was more desirable than for the CDG diet according to Milk Protein Score and Cornell Net Carbohydrate and Protein System. Dry matter intakes were similar among all diets. Milk yields (32.6, 31.7, 32.8, and 32.8 kg/d, respectively) were similar for cows fed all diets. Milk fat yields and percentages (3.72, 3.76, 3.67, and 3.63%) were unaffected by diet, but milk protein percentages (3.23, 3.26, 3.25, and 3.26%) tended to be higher when fed RPLM. Concentrations of most protein fractions in milk were similar for all diets, although beta-lactoglobulin was increased slightly when cows were fed BLEND diets. Lysine, Met, and Phe were indicated as the most limiting amino acids for all diets according to extraction efficiency and transfer efficiency of amino acid from blood by the mammary gland. Methionine status was apparently improved by RPLM supplementation; Lys status was improved by the BLEND diets. Milk yield and composition when cows were fed CDG were not further improved by feeding blends of protein sources or RPLM; however, such dietary changes improved Lys and Met status of the cows.
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September 2000

Dietary marine algae (Schizochytrium sp.) increases concentrations of conjugated linoleic, docosahexaenoic and transvaccenic acids in milk of dairy cows.

J Nutr 1999 Nov;129(11):2048-54

Dairy Science Department, South Dakota State University, Brookings, South Dakota 57007-0647, USA.

Modification of milk fat to contain long-chain (n-3) fatty acids and increased concentrations of conjugated linoleic acid has potential for improving health of consumers. Natural modification of milk through nutritional manipulation of diets for dairy cows is preferable to post-harvest modification. The objectives of this study were to increase the concentrations of beneficial fatty acids in milk fat by feeding a diet rich in (n-3) fatty acids from algae to dairy cows. Cows were fed a control diet, a diet containing algae (Schizochytrium sp.) protected against ruminal biohydrogenation, or a diet containing unprotected algae for 6 wk. Feed intake and milk production were recorded daily. Milk samples were obtained weekly for analysis of milk composition and profile of fatty acids. Percentage of fat in milk of cows fed algae was lower (P < 0.01) than in milk from cows fed the control diet; however, energy-corrected milk production did not differ (P > 0.05). Inclusion of algae in diets decreased (P < 0.01) feed intake. Milk fat from cows fed algae contained greater (P < 0.01) concentrations of conjugated linoleic acid, (n-3) fatty acids (particularly docosahexaenoic acid), and transvaccenic acid. Concentrations of docosahexaenoic acid were greater (P < 0.01) in milk fat from cows fed protected algae compared to milk fat from cows fed unprotected algae. Milk fat from cows fed algae contained lower (P < 0.05) concentrations of total saturated fatty acids compared to cows fed the control diet. In conclusion, milk fat can be modified through nutritional management of dairy cows to provide more favorable fatty acids for consumers.
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November 1999

Synchronization of carbohydrate and protein sources on fermentation and passage rates in dairy cows.

J Dairy Sci 1999 Aug;82(8):1779-90

Energy Metabolism Unit, Beltsville Agricultural Research Center-East, USDA-ARS, MD 20705, USA.

Four ruminally cannulated Holstein cows in midlactation were randomly assigned to a 4 x 4 Latin square design with a 2 x 2 factorial arrangement of treatments to evaluate two nonstructural carbohydrate sources (corn or barley) with two sources of ruminally undegradable protein (soybean meal or extruded soybean meal) on milk production, ruminal fermentation, and digesta passage rates. Milk production (25.1, 27.5, 23.8, and 23.5 kg/d for the corn and soybean meal, corn and extruded soybean meal, barley and soybean meal, and barley and extruded soybean meal, respectively) and dry matter intake per unit of body weight (3.9, 4.1, 3.7, and 3.7%) were greater for cows fed corn than for cows fed barley and were similar for cows fed soybean meal or extruded soybean meal. Concentrations of ruminal NH3-N were greater for cows fed the corn and soybean meal diet than for cows fed other diets (15.0, 10.4, 9.0, and 11.3 mg/dl). Rumen volatile fatty acid concentrations were greater for cows fed corn than barley (133, 139, 121, and 118 mumol/ml). Fractional passage rates of solids from the rumen were greater for cows fed the barley and soybean meal diet than cows fed the corn and soybean meal diet (3.4, 3.9, 4.2, and 3.8%/h), and ruminal liquid dilution rates were similar for cows fed all diets (11.2, 11.0, 11.1, and 11.9%/h). The attempt to synchronize ruminal nonstructural carbohydrate and crude protein degradability produced minimal benefits for midlactation dairy cows.
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August 1999

Response of lactating dairy cows to a cellulase and xylanase enzyme mixture applied to forages at the time of feeding.

J Dairy Sci 1999 May;82(5):996-1003

Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.

Fifty Holstein cows (20 primiparous and 30 multiparous) were used in an experiment to evaluate the dose response to a direct-fed cellulase and xylanase enzyme mixture applied to the forage portion (60% corn silage and 40% alfalfa hay) of a total mixed ration just prior to feeding. Cows were fed one of five treatment diets for 12 wk. Diets 1 through 4 were 55% forage: 45% concentrate and consisted of an untreated control and the control diet plus 0.7, 1.0, or 1.5 L of enzyme concentrate/tonne of forage dry matter, respectively. Diet 5 was an untreated 45% forage: 55% concentrate diet. Actual production of milk increased as much as 10.8% relative to the control diet with 1.5 L of enzyme, and production of fat and protein increased as much as 20 and 13%, respectively. The lowest concentration of enzyme treatment (0.7 L/tonne) accounted for approximately one-half of the production increases. The responses to enzyme-treated forages occurred 2 to 4 wk after the cows started to consume the treated forages, and the same responses were maintained throughout the remainder of the experiment. Cows that started to receive enzyme-treated forage during the first 100 d postpartum produced 9 to 15% more milk and 16 to 23% more energy-corrected milk than did cows fed the control diet. However, production was not increased when cows were in midlactation at the start of the experiment. Responses to enzyme-treated forages fed in 55: 45 forage to concentrate rations were similar to the response to increased proportions of concentrates fed with untreated forages at the 45:55 forage to concentrate ratio.
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May 1999

Milk production and composition from cows fed wet corn distillers grains.

J Dairy Sci 1999 Mar;82(3):574-80

Dairy Science Department, South Dakota State University, Brookings 57007, USA.

Twelve lactating Holstein cows were utilized in a repeated switchback design to evaluate milk production and milk fat composition responses to wet corn distillers grains. Total mixed diets consisted of 31.4% corn silage, 18.4% alfalfa hay, and either 50.2% of a concentrate mix that contained mostly corn and soybean meal or 19.4% of a concentrate mix that contained mostly corn and 31.2% wet corn distillers grains. The first 4 wk of each 6-wk period were for adaptation to diets; data were collected during wk 5 and 6 of each period. Although dry matter intake (22.1 vs. 19.7 kg/d) was lower when cows were fed the wet corn distillers grains diet, milk production (30.7 vs. 30.8 kg/d) was similar for cows fed both diets. Milk fat (3.60 vs. 3.85%) was slightly higher, and protein (3.06 vs. 2.84%) was lower, when cows were fed the wet corn distillers grains diet. Milk fat from cows fed wet corn distillers grains contained lower concentrations of saturated fatty acids and higher concentrations of long-chain and unsaturated fatty acids. The feeding of wet corn distillers grains increased the proportion of unsaturated fatty acids in milk fat without changing milk production.
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March 1999

Systems to evaluate the protein quality of diets fed to lactating cows.

J Dairy Sci 1998 Apr;81(4):1046-61

Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.

Ten multiparous and 5 primiparous cows (62 +/- 33 d in milk) were used in a replicated 5 x 5 Latin square design to investigate three dietary protein evaluation systems for lactating cows: milk protein score, Cornell Net Carbohydrate and Protein System, and an increase in Lys and Met to supply 15 and 5% of the predicted total essential amino acids (AA) in duodenal digesta, respectively. Five isonitrogenous diets were evaluated differently by the three systems. The milk protein score indicated that formulations of diets 2, 3, 4, and 5 were of equal quality and better for milk protein synthesis than was diet 1. The Cornell Net Carbohydrate and Protein System indicated that diets 3, 4, and 5 contained adequate AA, but diets 1 and 2 were deficient in Lys and Met. The increase in Lys and Met supply indicated that only diets 3 and 5 provided adequate Lys and Met. The dry matter intake, energy-corrected production, and fat production were lower, and 3.5% fat-corrected milk production tended to be lower, for cows consuming diets 4 and 5 than for cows consuming diets 2 and 3. Cows consuming diet 1 had lower percentages of crude protein, true protein, and casein N in their milk than did with cows consuming all other diets. Cows fed diets 3 and 5 had higher percentages of protein in milk than did cows fed other diets. Protein production was greater, and casein N tended to be greater, for cows consuming diet 3 than for cows consuming diet 2. Although all three systems had validity, the system by which Lys and Met were increased most accurately predicted milk protein percentages and production.
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April 1998

Evaluation of corn distillers grains and ruminally protected lysine and methionine for lactating dairy cows.

J Dairy Sci 1998 Feb;81(2):482-91

Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.

Twelve multiparous Holstein cows averaging 57 d (36 to 77 d) postpartum at the start of the experiment were utilized in a replicated 4 x 4 Latin square design. Dietary protein supplements were 1) soybean meal, 2) soybean meal plus ruminally protected Lys and Met, 3) corn distillers grains, and 4) corn distillers grains plus ruminally protected Lys and Met. Dry matter intakes were lower for cows fed diets containing soybean meal than for cows fed diets containing corn distillers grains. Milk yield increased with the corn distillers grains (34.3, 34.0, 35.3, and 36.7 kg/d for cows fed diets 1 through 4, respectively), especially when supplemented with ruminally protected Lys and Met. Milk protein yield and percentage were increased by amino acid supplementation. Milk fat yield and percentage were unaffected by diet. The only milk protein fraction affected was nonprotein N, which was lower in the milk of cows fed corn distillers grains. Lysine, Met, and Phe were indicated as the most limiting amino acids for all diets when using amino acid extraction efficiency and transfer efficiency to indicate limiting amino acids. When corn distillers grains were supplemented with ruminally protected Lys and Met, milk yield and milk protein yield and percentage increased because the diet containing corn distillers grains was probably deficient in Lys.
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February 1998

Ruminal degradation, amino acid composition, and estimated intestinal digestibilities of four protein supplements.

J Dairy Sci 1998 Feb;81(2):454-61

Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.

Blood meal, canola meal, corn gluten meal, and menhaden fish meal were weighed into dacron bags for incubation in the rumens of two ruminally cannulated Holstein cows on 3 d for 0, 3, 6, 12, 18, and 24 h. Both the original feeds and the residues remaining after 12 h were analyzed for amino acid (AA) content. Canola meal was degraded the most extensively in the rumen, and blood meal was degraded the least extensively. Intestinal digestibilities estimated using an enzymatic in vitro technique were all high; canola meal was estimated to have the lowest intestinal digestibility, and corn gluten meal was estimated to have the highest intestinal digestibility. The AA profile of the 12-h residues differed only slightly from the AA profile of the original protein supplements. A comparison of the AA profiles of feed residues with milk protein showed that isoleucine was the first-limiting AA in blood meal, canola meal, and fish meal, and lysine was the first-limiting AA in corn gluten meal. Although canola meal was extensively degraded in the rumen, its 12-h residue still provided an estimated AA profile to the intestinal tract that was closest to the AA profile of milk protein. Blood meal and corn gluten meal are good sources of ruminally undegradable protein but are deficient in some AA and should probably be fed only in combination with other protein sources that complement their AA profiles.
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http://dx.doi.org/10.3168/jds.S0022-0302(98)75597-3DOI Listing
February 1998

Response of lactating cows to supplemental unsaturated fat and niacin.

J Dairy Sci 1997 Jul;80(7):1329-38

Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.

Responses to supplemental unsaturated fat or niacin in a 2 x 2 factorial arrangement were evaluated with 16 lactating Holstein cows in a replicated Latin square with 4-wk periods. Total mixed diets contained (dry matter basis) 25% alfalfa hay, 25% corn silage, and 50% concentrate mixture. Diets were the control or the control supplemented with unsaturated fat (3% of dry matter of the total mixed diet from extruded soybeans, which replaced soybean meal and portions of the corn and barley in other concentrates), niacin (12 g/d of nicotinic acid), or both unsaturated fat and niacin. Milk production increased with the addition of fat but was unaffected by the addition of niacin (31.9, 35.1, 32.2, and 35.5 kg/d). Milk fat percentages were unaffected by the addition of fat or niacin to the diet, but proportions of both unsaturated and long-chain fatty acids increased with supplemental fat and were further increased with niacin in addition to fat; however, niacin was ineffective without fat. Milk protein percentages were lower with supplemental fat but were unaffected by niacin. Dry matter intake; ruminal volatile fatty acids, pH, and ammonia; serum urea; plasma glucose; and plasma amino acids were unaffected by supplemental fat or niacin. The first-limiting amino acid for milk protein synthesis was lysine for control diets and methionine for diets with supplemental fat. Supplementation of the diet with an unsaturated fat source increased milk production and the proportion of unsaturated fatty acids in milk, but niacin supplementation had no substantial influence on milk production and only a minor influence on milk fatty acid content.
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July 1997

Lactational evaluation of protein supplements of varying ruminal degradabilities.

J Dairy Sci 1997 Feb;80(2):385-92

Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.

Twelve lactating Holstein cows (9 multiparous and 3 primiparous) were used in a replicated 3 x 3 Latin square design with three periods of 4 wk each to evaluate diets containing three protein supplements that varied in ruminally undegradable protein and amino acid (AA) composition. Diets contained either 44% crude protein (CP) solvent-extracted soybean meal, expeller (mechanically extracted) soybean meal, or a blend of animal and vegetable proteins as the protein supplement. The animal and vegetable blend consisted of equal portions of protein from blood meal, corn gluten meal, meat and bone meal, and soybean meal. All diets contained 33.3% alfalfa haylage, 16.7% corn silage, and 50% of the respective concentrate mix (dry matter basis). Diets contained 17.4, 17.8, and 17.8% CP and 34, 45, and 45% of CP as ruminally undegradable protein, respectively. Dry matter intake, milk production and composition, and body weight were similar among treatments. Uptakes of AA by the mammary gland were similar among treatments. The apparent first-limiting AA for each diet was likely Met, but Lys and Phe were also potentially limiting. Varying degrees of protein degradability and AA composition within the range of this study did not affect lactational responses, indicating that all of these protein supplements were adequate to support milk production.
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http://dx.doi.org/10.3168/jds.S0022-0302(97)75948-4DOI Listing
February 1997

Optimizing the utilization of animal fat and ruminal bypass proteins in the diets of lactating dairy cows.

J Dairy Sci 1997 Feb;80(2):343-52

Dairy Science Department, South Dakota State University, Brookings 57007-0647, USA.

Fifty cows were used to evaluate the lactational response to diets containing additional fat as tallow and increased amounts of RUP (bypass proteins) with or without molasses. Cows were blocked by parity and calving date and randomly assigned to one of five diets from wk 4 to 16 postpartum. Treatments were 1) control (soybean meal), 2) bypass proteins (blood meal, meat and bone meal, corn gluten meal, soybean meal), 3) molasses and bypass proteins, 4) fat and bypass proteins, and 5) molasses, fat, and bypass proteins. Cows were fed for ad libitum intake a total mixed diet that contained 25% corn silage, 25% alfalfa hay, and 50% concentrate mix (dry matter basis). Production of milk was higher for cows fed diets containing fat and bypass proteins; molasses and bypass proteins; and molasses, fat, and bypass proteins than for cows fed the diet with bypass proteins alone, but production was similar for cows fed the control diet and diets containing bypass proteins alone. Production of milk was similar for cows fed the diet with molasses and bypass proteins and for cows fed the diet with fat and bypass proteins. Milk protein percentages were higher for cows fed the diet with molasses and bypass proteins than for those fed the diet containing fat and bypass proteins. The dry matter intake, body weight gains, and body condition scores were unaffected by treatment. For all diets, Met, Lys, and Phe were the first three limiting essential amino acids for milk protein synthesis. Production was increased by including either fat or molasses with bypass protein, but there was no clear advantage of including both fat and molasses in the diet.
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February 1997
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