Lactational performance of high producing dairy cows fed diets containing salmon meal and urea.
Thirty Holstein cows were used in a 12-wk trial to study the effects of salmon meal and urea on lactational performance. Two experimental diets, one containing 5.6% salmon meal and the other 5.2% salmon meal plus .42% urea, were compared with a soybean meal control diet. Salmon meal and urea replaced a portion of the soybean meal. Dietary undegraded intake protein levels (expressed as percentage of CP) were 28.8, 35.6, and 32.4% for soybean meal, salmon meal, and salmon meal plus urea. Total mixed diets (average 17.3% CP, 17.6% ADF) consisting of 60% concentrate mixture and 40% bromegrass silage (DM basis) were fed twice daily. Total DMI was lower with salmon meal compared with soybean meal (20.2 versus 22.2 kg/d); salmon meal plus urea (21.2 kg/d) was intermediate. Actual milk production was similar for all diets (average 41.1 kg/d). Percentage milk fat and 4% FCM yield were lower with salmon meal (2.56%, 31.6 kg/d) and salmon meal plus urea (2.50%, 31.4 kg/d) than with soybean meal (3.03%, 35.9 kg/d). Gross efficiency (weight FCM/weight DMI) was higher for soybean meal than for salmon meal and salmon meal plus urea. Acetate: propionate tended to be higher with the soybean meal diet. The use of a high oil fish meal to provide a source of rumen undegraded intake protein, alone or in combination with urea, resulted in a decrease in milk fat percentage and yield without any beneficial effects on milk production or lactational efficiency.
Windschitl
P M
PM
Agricultural and Forestry Experiment Station, University of Alaska, Palmer 99645.
D000641:Ammonia / Q000032:analysis; D000821:Animal Feed; D000818:Animals; D001806:Blood Urea Nitrogen; D001835:Body Weight; D002417:Cattle / Q000502:physiology*; D004435:Eating; D005227:Fatty Acids / Q000032:analysis; D005232:Fatty Acids, Volatile / Q000032:analysis; D005260:Female; D005396:Fish Products; D007774:Lactation; D008055:Lipids / Q000032:analysis; D008892:Milk / Q000032:analysis / Q000378:metabolism; D012417:Rumen / Q000737:chemistry; D012474:Salmon; D014508:Urea / Q000008:administration & dosage*
D005227:Fatty Acids; D005232:Fatty Acids, Volatile; D008055:Lipids; D000641:Ammonia; D014508:Urea