Effects of Dietary Energy Level on Growth and Reproductive Performances of HF Crossbred Heifers
Phạm Hữu Phước
Abstract
An on-farm feeding trail was carried out to evaluate the effect of optimal dietary energy level , on growth and reproductive performances of crossbred dairy cattle. A total of of 18 fifty-percent HF crossbred heifers at 12 months of age and with an average body weight of 224 kg were allocated into three groups to be fed on different diets for99 days. The experimental diets were composed of local meadow grass plus one of three concentrates, viz. commercial Proconco C40 (NT1), experimental AG1 (NT2 containing 4.5% catfish oil) or AG2 (NT3, 9% catfish oil). It was found that the average daily gain (ADG) was 0.80 kg, 0.75 kg and 0.56 kg; for feed conversition ratio (FCR) was 7.60, 7.90 and 10.05; percetage of heifers showing estrus was 100%, 83.83, and 66.67; mating rate was 83.93, 66.67 and 50%; BCS before first mating was 2.85, 3.06 and 2.92, and after first mating was 3.45, 3.50 and 3.56 for NT3, NT2 and NT1, respectively. It was therefore concluded that AG1 and AG2 with high energy levels diets in the feeding trial were good for HF cross-bred heifers under the local conditions of the Mekong Delta