The effects of supplemental protease enzymes on production variables in lactating Holstein cows

• Main Authors: Ekin Sucu, Amir Nayeri, Maria V. Sanz-Fernandez, Nathan C. Upah, Lance H. Baumgard
• Format: Article
• Language: English
• Published: Taylor & Francis Group 2014-05-01
• Series: Italian Journal of Animal Science
• Subjects: Dairy cows, Feed efficiency, Milk components, Milk production, Protease enzyme
• Online Access: http://www.aspajournal.it/index.php/ijas/article/view/3186

A study was conducted to examine the effects of supplemental dietary protease enzymes on production variables in dairy cattle. Ninety-six multiparous lactating Holstein cows (624±62 kg body weight and 154±104 days in milk) were blocked according to parity, days in milk, and previous milk production and randomly assigned to a control total mix ration (TMR) or a TMR containing a blend of supplemental protease enzymes (PE; 4 g/cow/d) in a crossover design with two 21-day experimental periods. Daily pen milk yield and dry matter intake (DMI) were recorded and milk composition from all cows was determined on d 15, 17, 19 and 21 of each period. There was no treatment effect on milk yield (37.6 kg/d), but supplemental PE-fed cows consumed less DMI (P<0.05) compared to controls and therefore tended to have improved feed efficiency (P=0.06). Feeding supplemental PE decreased blood urea nitrogen (P<0.05) compared to the control cows. However, feeding PE had no effect on milk fat and protein content but tended (P=0.08) to increase milk lactose concentration and tended (P=0.10) to decrease milk urea nitrogen levels and somatic cell score. Results indicate that supplemental PE may enhance production efficiency and improve parameters of nitrogen status.