Age and Weight at Puberty in Nili-Ravi Buffalo
Heifers Reared on Three Dietary Energy Restriction Periods followed
by Compensatory Growth
M. I. Anjum*, A. Azim,
M. A. Jabbar1, M. Anwar2 and I. H. Mirza
Animal Nutrition
Program, Animal Sciences Institute, National Agricultural Research
Centre, Islamabad; 1University of Veterinary and Animal
Sciences, Lahore;2Animal
Reproduction Program, Animal Sciences Institute, National Agricultural
Research Centre, Islamabad, Pakistan
*Corresponding author:mianjum_narc@yahoo.com
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.
Key words:
Buffalo heifers,
Compensatory growth,
Conception rate,
Dietary energy restriction, Pubertal age and weight