Departments of Animal Biochemistry and Dairy Cattle Nutrition, National Dairy Research Institute, Karnal132001, India
1Present address : OB/GYN Ottawa Civic Hospital School of Medicine, University of Ottawa 1053 Carting, Ottawa, Ontario, Canada KIY 4E9.
Online published on 5 January, 2012.
Ten crossbred (Brown Swiss x Sahiwal) dairy cows were distributed into two groups of five each. While the tows in group I were optimum fed as per their requirements, those in group II were underfed at 61 per cent lower DCP and 22 per cent lower TDN than their requirements. The feeding regime was followed for a period of one year. Reproductive behaviour of the cows was determined by studying the pattern of plasma progesterone concentrations and the external oestrus symptoms in both the groups. Undernutrition resulted into long anoestrous periods in cows. Oestrous cycle length was significantly higher (P < 0.01) in group II than in group I (21.37 ± 1.73 vs. 19.86 ± 1.27 d). Undernutrition lowered the occurrence of oestrus hy 31.70 per cent. Plasma progesterone levels remained low during anoestrous in both the groups. Mean plasma progesterone peak during oestrous cycles in group I (3.20 ± 1.77 ng/ml) appeared on day 12.55 ± 1.97 of the cycle and the corresponding progesterone peak (2.87 ± 1.40 ng/ml) in group II appeared on day 13.66 ± 2.72 of oestrous cycle. Progesterone peak concentration during oestrous cycle in group I did not differ from that of group II, whereas, the progesterone peak day during oestrous cycle was delayed in group II as compared to that of group I (P < 0.01).
