EFFECT OF DIETARY ZINC SUPPLEMENTATION ON OVARIAN FOLLICULOGENESIS IN BUFFALO HEIFERS

A study was undertaken to investigate the effect of zinc (Zn) supplementation on ovarian folliculogenesis in buffalo heifers. Eighteen buffalo heifers with an average body weight of 278.7 +/- 16.82 kg were randomly allotted to 3 groups in a completely randomized design. The dietary treatments were viz., Basal diet (BD; 29.72 ppm Zn from feed ingredients), BD supplemented with 80 and 140 ppm Zn as ZnSO4 7H(2)O (22% Zn). Heifers were fed the respective diets at 3% of body weight to meet the nutrient requirements (NRC, 2001) of dairy cattle except Zn throughout for an experimental period of 150 days. After 2 months of feeding trial, ovarian folliculogenesis study was made on all animals daily with help of B- mode linear array ultrasound scanner equipped with 7.5 MHz transducer. The proportion of large follicles (> 8 mm) was higher (P< 0.05) with 140 ppm (5.29%) Zn supplementation followed by 80 ppm (3.38%) compared to no Zn supplementation. However, no large sized follicles on ovary were observed in heifers supplemented with no Zn. While the mean number of small (3 to 5 mm) and medium follicles (5 to 8 mm) were not affected by Zn concentration in diet. The study indicated significant effect of Zn supplementation on ovarian follicular development with greater number of large follicles with 140 ppm Zn supplementation.