Supplementation of Holstein dairy calves fed two levels of crude protein with methionine and lysine

This study aimed to investigate various levels of crude protein (CP) in starter diets and their supplementation with amino acids (AAs) on efficiency, health, and serum metabolites of dairy calves. Ninety-six newborn Holstein calves were allocated to eight treatments, namely T1) 18% CP unsupplemented starter, T2) T1 supplemented with additional 20% methionine, T3) T1 with additional 20% lysine and 20% methionine, T4) T1 with additional 20% lysine, T5) 22% CP unsupplemented starter, T6) T5 supplemented with additional 20% methionine, T7) T5 supplemented with additional 20% lysine and 20% methionine, and T8) T5 supplemented with additional 20% lysine. Consumption of the starter was not influenced by the level of CP. Calves that received the unsupplemented 22% CP starter had higher average daily gain (ADG) and final weight. But no significant differences among diets were found in feed efficiency. Skeletal growth did not exhibit a clear trend. Calves that received T3 had fewer bouts of diarrhea and reduced body temperature. However, there were no significant dietary effects on immunoglobin G (IgG) or total protein concentration in blood. T1–T3 decreased serum urea concentration. Thus, use of T3 resulted in an improved amino acid balance, and was less expensive than the 22% CP starter.Keywords: amino acid, feed intake, immunity, pre-ruminant cal

The effects of different levels of sodium caseinate on rumen fermentation pattern, digestibility and microbial protein synthesis of Holstein dairy cows

This study was conducted to investigate the effects of different levels of peptide supplementation on rumen fermentation pattern, digestibility and microbial protein synthesis. Three rumen-cannulated Holstein dairy cows were used in a 3 × 3 Latin square experiment within 21 days period. The ruminal infusion of sodium caseinate (CN) was 0 (control), 50 and 100 g/d. Dry matter intake, milk yield and composition , total tract apparent digestibility of nutrient, rumen parameters and purine derivatives inurine of cows were measured. Results showed that dairy cows received sodium caseinate, had significantly increased microbial protein synthesis, milk fat yield, acetate and branched chain fatty acids concentrations in rumen fluid and fiber digestibility compared with the control treatment (P <0.05). CN significantly affected the concentrations of rumen ammonia nitrogen (NH3-N), rumen peptide nitrogen (Pep-N) and the ratio of rumen ammonia nitrogen/ rumen peptide nitrogen (P < 0.05) and consequently blood urea nitrogen, milk urea nitrogen and urinary urea nitrogen concentrations. However digestibility of dry matter and crude protein did not differ among treatments. In conclusion, if the optimum level of NH3-N/Pep-N was the best compromise among the need for rumen fermentation, microbial protein synthesis and nitrogen excretion through urine in animal, the recommended level from this study would be 0.86 in rumen fluid

Adding wheat to a pre-partum diet of Holstein cows favours post-partum protein utilization and benefits calcium status

This study evaluated the effects of replacing corn with wheat on the lactation performance, ruminal fermentation, plasma metabolites and hormonal profiles of multiparous Holstein cows. Thirty-four multiparous cows were divided into two equal groups, based on parity, body condition score, and bodyweight. The basal diet was supplemented with 186 g/kg corn or wheat, and was offered from day -28 (±7) relative to the date of expected calving. After calving, all cows received the same diet for four weeks (day +28). The wheat diets increased (P <0.05) the body condition score in the peri-parturient period and caused greater changes in dry matter intake and bodyweight post-partum, with no differences in energy balance compared with the corn diets. Further, the wheat increased (P <0.05) the concentration of propionate in the rumen, thus reducing the ratio of acetate to propionate, and produced (P <0.05) more milk and milk protein, but had reduced levels of urea nitrogen in the milk and serum. Similarly, the wheat diets increased (P <0.05) the plasma concentrations of albumin and glucose, and reduced (P <0.05) triglycerides with no effect (P >0.10) post partum on insulin, cortisol, β-hydroxybutyric acid and aspartate aminotransferase. The replacement of corn with wheat increased (P <0.05) plasma calcium and reduced non-esterified fatty acids around calving (day 0±1) and post-partum (days 0 to +28), and reduced urinary pH during the last week relative to the date of expected calving.Keywords: calving, energy balance, grain source, peri-parturient perio

Fat source and dietary forage-to-concentrate ratio influences milk fatty-acid composition in lactating cows

201