Abstract

The effects of two stressors (level of feeding: 4% bodyweight, FI, and 3% bodyweight, RI; and altered lying time: free choice, LF, and prevention of lying from 1500 to 0645 h daily, LD) allocated in a 2x2 factorial design on milk yield and composition of Jersey cows (n=32) were studied. Stressors were applied for 7 days following an 8-day pre-treatment period. Composite milk samples were collected at milkings on days 2-3 of pre-treatment and during the last 4 days of treatment. Fat%, milk weight (am, pm and total daily) and mean daily yields of fat, casein, lactose and total milksolids were not affected by treatment. Protein%, protein yield and casein% were lower with RI (protein%: 3.66 and 3.53, sem=0.02, P<0.01; protein yield: 0.54 and 0.50 kg, sem=0.01, P=0.05; casein%: 2.84 and 2.77, sem=0.02, P<0.05 for FI and RI, respectively). There were no significant interactions between treatments. Protein content of milk was reduced by medium-term feed restriction, but lying deprivation had minimal effects.

GA, Verkerk, AD Fisher, CJ Morrow, and LR Matthews

Proceedings of the New Zealand Society of Animal Production, Volume 59, , 192-194, 1999