Pakistan Veterinary Journal (Jun 2012)
Age and Weight at Puberty in Nili-Ravi Buffalo Heifers Reared on Three Dietary Energy Restriction Periods followed by Compensatory Growth
Abstract
Twenty two weaned heifers about 6-8 months old and 98.57±5 kg average BW were divided into two groups; either fed continuously as per NRC recommendations (control) or stair-step nutritional regimen (SSNR). For control group total mixed rations were formulated by adapting the large dairy breeds heifer’s nutrient requirements for growth rate of 0.6 kg/day considering body weight of 100, 200 and 300 kg at the beginning of phase I (from 8 to 13 months), phase II (from 14 to 19 months) and phase III (from 20 to 25 months), respectively. The SSNR group, in each phase started on restricted energy diet (80% ME of control) for 4 months and ended with compensatory energy (120% ME of control) for 2 months. There was no difference in daily DMI, weight gain and FCR in heifers raised on SSNR versus control diet. One heifer from each group had retarded growth, and was excluded from reproductive studies. Proportion of heifers attaining puberty by 18-23 months of age did not differ (P>0.05) between SSNR (80%) and control group (70%). Pubertal age (649±21.76 vs 639±21.46 days) and BW (382±14.00 vs 364±12.48 kg) were not affected by SSNR compared to control diet. Similarly, differences in services per conception or conception rate between the two groups were non-significant. However, SSNR reduced feed cost by Rs 16.69/kg BW gain compared to control. It can thus be concluded that SSNR shows economic advantage in rearing of buffalo heifers from post-weaning to conception age without any negative effect on reproductive efficiency compared with heifers fed as per NRC recommendations.
