Performance Of Early Lactating Cows Research Articles

Evaluating the effects of fibrolytic enzymes on rumen fermentation, omasal nutrient flow, and production performance in dairy cows during early lactation

This study was performed to evaluate the effects of pre-treating a barley-silage-based diet with an exogenous fibrolytic enzyme derived from Trichoderma reesei (FETR, a mixture of xylanase and cellulase) on lactation performance, omasal nutrient flow and digestibility, rumen fermentation characteristics, and rumen pH profile in Holstein dairy cows during early lactation. The dairy trial was conducted using nine Holstein dairy cows (averaging 46 ± 24 days in milk and 697 ± 69 kg body weight, six cows were fitted with a rumen cannula, and three were non-cannulated). Two groups of cows were randomly assigned to each of the dietary treatments in a crossover design: control (without FETR supplementation) and supplemented [with 0.75 mL of FETR·kg−1 dry matter (DM) of the diet based on our previous study]. The application of FETR tended to decrease the DM intake compared with control. There were no effects of FETR (P > 0. 10) on omasal nutrient flow and digestibility, rumen fermentation characteristics, and rumen pH profile. In conclusion, this study lacks evidence that the fibrolytic enzyme (at a level of 0.75 mL of FETR·kg−1 DM) can affect nutrient digestibility, ruminal fermentation, and the performance of early-lactation cows. Further study with larger animal trials are needed.

Monensina sódica sobre vacas em fase inicial de lactação: produção de leite e peso vivo

Avaliou-se o efeito do fornecimento de monensina sódica no desempenho de vacas leiteiras em fase inicial de lactação, cuja alimentação, em sua dieta total no cocho, compôs-se em 81,4% de silagem de milho e 18,6% de concentrado, em que se fez uso de maior proporção de silagem de milho de que concentrado. Foram utilizadas 14 vacas multíparas 7/8 Holandês, aos 20±10 dias pós-parto aproximadamente, com média de 22±0,5kg vaca-1 dia-1 de leite, em delineamento de blocos casualizados, adotando-se o esquema de parcelas subdivididas no tempo, em modelo de medidas repetidas. Os tratamentos nas parcelas foram diferenciados pela presença (200mg animal-1dia-1) ou ausência da monensina na ração e, nas subparcelas, pelos diferentes períodos de avaliação. Não se observaram diferenças no consumo em matéria seca da dieta, conversão alimentar, produção de leite in natura e corrigida e peso vivo nas médias diárias de cada período. No entanto, a produção de sólidos totais foi superior para os tratamentos com o ionóforo, sinalizando que a administração da monensina sódica para vacas no início de lactação modifica o rendimento em produção de leite.

Effect of Dietary Rumen Protected Methionine and/or Choline Supplementation on Rumen Fermentation Characteristics and Productive Performance of Early Lactating Cows

Effect of Dietary Rumen Protected Methionine and/or Choline Supplementation on Rumen Fermentation Characteristics and Productive Performance of Early Lactating Cows

Effects of Partial Replacement of Berseem Hay by Corn Stalk with or without Calcium Salts of Fish Oil on Rumen Fermentation, Productive and Reproductive Performance of Early Lactating Cows

Effects of Partial Replacement of Berseem Hay by Corn Stalk with or without Calcium Salts of Fish Oil on Rumen Fermentation, Productive and Reproductive Performance of Early Lactating Cows

NDFと脂肪含有量に富む食品製造副産物の給与が泌乳前期の乳生産に及ぼす影響

NDFと脂肪含有量に富む食品製造副産物の給与が泌乳前期の乳生産に及ぼす影響

Performance and nutrient digestibility by dairy cows treated with bovine somatotropin and fed diets with steam-flaked sorghum or steam-rolled corn during early lactation.

This study compared effects of exogenous bovine somatotropin (bST) on the performance of early lactation cows fed diets differing in ruminally degradable starch. Thirty-two Holstein cows (24 multiparous) in early lactation (5 d in milk) were divided into four groups and fed diets containing 39% grain as steam-flaked sorghum or steam-rolled corn with or without exogenous bST for 90 d. Grain processing did not affect dry matter intake as a percentage of body weight or yields of milk, but steam-rolled corn improved efficiency of feed utilization during the first 45 d of the study. Cows receiving bST had lower dry matter intake during the first 45 d of treatment. Milk yield and efficiency of feed utilization were increased by bST treatment, and milk yield response was greater during the first half than during the second half of the study. Milk composition and yield of milk components did not differ among treatments. Flaked sorghum increased in vitro starch hydrolysis and digestibilities of dry matter, organic matter, and starch, but neither method of grain processing nor bST affected digestibilities of crude protein, acid detergent fiber, or neutral detergent fiber. Grain type did not affect milk yield, and responses to bST were lower from 7 to 13 wk than from 1 to 6 wk prepartum.

Supplementation of Rumen-Undegradable Protein to the Diets of Early Lactation Holstein Cows on Grass Pasture

The objectives were to evaluate supplements differing in rumen-undegradable protein (RUP) on the performance of early lactation cows on grass pasture. Twenty-four Holstein cows averaging 68 d of lactation and 39.8 kg/d of milk were rotationally grazed on predominantly Dactylis glomerata pasture for 8 wk. Cows were blocked according to parity, milk yield, and days of lactation and were randomly assigned to a grain mixture with a low or high RUP content. Pasture and the low and high RUP grain mixtures averaged 25.6, 14.7, and 13.7% crude protein and 4.0, 7.0, and 8.4% RUP, respectively (dry matter basis). Grain was fed twice daily at 1 kg/4kg of milk, pasture provided all forage in the diet, and grain consumption was similar (8.9 kg/d per cow) for cows on both treatments. Total dry matter intakes estimated using chromic oxide were 19.9 and 20.9 kg/d for cows fed low and high RUP grain mixtures. Milk yields did not differ between treatments; means were 34.2 and 35.5 kg/d for cows fed low and high RUP grain mixtures. Multiparous cows tended to yield more milk (36.2 vs. 34.5 kg/d) and milk protein (1.06 vs. 0.98 kg/d) when fed the high RUP grain mixture. Concentrations of plasma urea N and nonesterified fatty acids were unaffected by treatment and averaged 18.7 mg/dl and 307 μeq/L, respectively. Results indicated that a supplemental grain mixture with a high RUP content did not alter milk yield of high yielding cows when pasture was the sole forage; however, milk protein yield tended to be greater for multiparous cows fed the high RUP grain mixture.

Impacts of Dietary Forage Source on Performance of Early Lactating Cows.

Impacts of Dietary Forage Source on Performance of Early Lactating Cows.

Evaluation of Oregon Produced Fish Meals in a Dairy Cattle Ration

The purpose of this study was to evaluate performance of early lactation cows, fed a typical Oregon dairy ration, supplemented with corn gluten meal or one of three fish meals. The fish meals, supplemented at 3.5% of the ration dry matter, included a ruminant grade menhaden from Zapata Haynie, Hammond, LA; a bottom fish produced by Ocean Proteins in Charleston, OR; and a white fish meal produced by Arctic Alaska and Depoe Bay Fish in Newport, OR. Sixteen multiparous Holstein cows were blocked into four groups of four cows for this 4×4 crossover design with 3-wk periods. No differences were detected for cows fed the corn gluten or fish meal diets for dry matter intake. Corn gluten meal and ruminant grade menhaden provided the highest amount of ruminally undegradable protein intake. Cows supplemented with corn gluten meal and ruminant grade menhaden had significantly higher milk production than cows supplemented with the bottom fish meal; cows fed the white fish meal had milk production similar to all other groups. There were no significant differences between diets for 4% fat corrected milk, milk fat, or protein production, or milk fat or protein content. Neither an oxidized off-flavor nor other off-flavors were detected in the milk produced by cows supplemented with fish meal. In 1993, there was no economic advantage to feeding Oregon produced FM compared to ruminant grade menhaden or corn gluten meal. However, the fish meals were essentially equally productive and could become profitable if economic conditions change.

Effects of Source and Level of Undegraded Intake Protein on Nutrient Use and Performance of Early Lactation Cows

At parturition, groups of six cows (two primiparous) were assigned randomly to experimental diets composed of wheat silage, concentrate containing 11.4% yellow grease, corn, and supplemental protein sources. Protein sources were soybean meal, heated soybean meal, and a combination of corn gluten and heated soybean meals. Intakes of DM, NDF, and NEL were not affected by undegraded protein levels (trial 1). Milk and 4% FCM yields and percentages of CP, lactose, SNF, and total solids were not influenced by protein source. Mobilization of body tissue was accelerated by heated soybean meal. During wk 1 to 4 postpartum, efficiency of NEL utilization was greater for cows receiving the combination treatment than for those receiving the soybean meal treatment. During wk 4 to 8, cows fed the heated soybean treatment utilized NEL more efficiently for milk yield than cows fed the combination treatment. Efficiency of utilization of absorbed protein was not affected by level of undegraded protein. At wk 9, fat was removed from the concentrate, and a second trial was conducted. Intakes of DM and NEL were reduced for cows fed the combination treatment. Milk yield and composition and efficiency of utilization of NEL and absorbed protein were not affected by level of undegraded protein.

Dietary Fat, Protein Degradability, and Calving Season: Effects on Nutrient Use and Performance of Early Lactation Cows

Twelve multiparous Holstein cows calving in fall and 12 calving in summer were blocked into four groups and used in a 2 × 2 × 2 factorial to determine the effects of season of calving, dietary fat, and protein degradability on milk production and efficiency of NEL utilization in a 16-wk study. Blocks were assigned randomly to one of four dietary treatment combinations: 1) control concentrate plus soybean meal (high degradability protein supplement); 2) control concentrate plus a mixture of heated soybean meal and corn gluten meal (low degradability protein supplement); 3) a blend of the control concentrate and a concentrate containing 12.1% fat to provide 1kg d−1 fat, plus soybean meal; and 4) concentrate as in diet 3 plus heated soybean meal and corn gluten meal. Nutrient intake, milk yield and composition, BW changes, and daily ambient temperature were monitored. Intake of DM appeared to be related to NDF intake but was not affected by fat, protein degradability, or calving season. Intake of NEL was increased by feeding fat. Digestibilities of DM and CP were increased and fiber was decreased by feeding fat. Percentage and yields of milk fat, SNF, and protein and 4% FCM production were higher in cows calving in fall. Milk fat percentage was low in all cows in the study. Efficiency of energy utilization for milk production was decreased in cows fed fat and calving in the summer and by low protein degradability during wk 5 to 8 of lactation. At high concentrate intake, calving season had more effect on milk production than level of fat or protein degradability.

Addition of Buffers to High Quality Alfalfa Hay-Based Diets for Dairy Cows in Early Lactation

Beginning 4 wk postpartum, 14 Holstein cows were paired according to expected calving date and lactation number and assigned randomly to one of two treatments in a single reversal experiment designed to study the effects of added buffers to high quality alfalfa hay-based diets. Cows were offered daily 14.5kg of concentrate containing 0 or 2% sodium bicarbonate and .5% magnesium oxide (as fed), plus free choice high quality alfalfa hay in a ratio of forage:grain approaching 50:50 (dry matter). No differences were in milk production, milk fat percentage, fatcorrected milk, or dry matter intake. Dry matter intake of grain was decreased with addition of buffers. Kilograms fat-corrected milk per kilogram of dry matter intake were 1.41 and 1.45 for control and buffered diets. No differences were significant for rumen pH, ammonia concentration, molar proportions of acetate and propionate, or ratio of acetate: propionate. Concentrations of total volatile fatty acids were higher for cows fed the buffered diet. No differences were in blood acid-base status or in various serum metabolites. Urine pH was 8.11 and 8.20 for control and buffered diets. Fractional urinary excretion of magnesium and sodium was greater when cows consumed the buffered diet. Diet digestibilities and rate of passage were not affected by dietary buffers. Addition of sodium bicarbonate plus magnesium oxide did not improve performance of early lactation cows fed high quality alfalfa hay as the sole forage.