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National Dairy Research Institute, Karnal

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20211
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Subject: Veterinary Gynaecology and Obstetrics × Author: DEBBARMA, KINKAR ×
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    ThesisItemOpen Access
    Effect of bypass fat supplementation on onset of puberty in heifers and estrus in postpartum dairy cows
    (ICAR-NDRI, KARNAL, 2021) DEBBARMA, KINKAR; KARUNAKARAN, M.
    Delayed onset of puberty and postpartum anoestrus in dairy cows are the two most frequent conditions in Indian subcontinent caused by undernutrition or energy deficiency. Bypass fat can increase the energy density of ration without having any adverse effects on feed intake and digestion. The experiment was conducted to investigate the effects of supplementation of bypass fat on the onset of puberty in dairy heifers and the onset of postpartum estrus in lactating dairy cows. The trial was conducted with 12 prepubertal heifers and 14 lactating dairy cows divided into control (C) and Treatment (T) groups. The ration for the experimental animals (heifers and cows) in control group were not supplemented with bypass fat, whereas heifers in treatment group received bypass fat @ 50g/day/h for a period of 150 days and the ration of postpartum cows were supplemented with bypass fat @ 10g/kg milk yield/day/cow for a period of 90 days from the day of calving. Bypass fat supplementation significantly (P<0.05) improved the mean live body weight, BCS and BFT in heifers, but no significant (P>0.05) effect was seen in postpartum cows. Bypass fat supplementation had no significant (P>0.05) effect on the proportion of heifers attaining puberty (50.00 vs. 33.33%) as well as the age at onset of puberty (605.67±22.67 vs. 626.50±28.50 days). There was no significant (P>0.05) difference observed between the control and treatment groups in the mean size of dominant follicle, CL and ovary in both heifers and postpartum cows, except the ovarian size which was significantly (P<0.05) larger in supplemented postpartum cows. The number of small, medium and large follicles didn‟t vary between groups (P>0.05) in heifers but the number of medium follicles was significantly higher (P<0.05) in bypass fat supplemented postpartum cows during the study period. No significant (P>0.05) effect on plasma NEFA level was observed, however plasma glucose level was significantly (P<0.05) higher in both bypass fat supplemented heifers and lactating cows. No significant effect (P>0.05) of bypass fat supplementation was observed on the days of uterine involution. The onset of postpartum estrus (24.57±2.16 vs. 31.71±2.04 days) and days to first AI (44.43±2.75 vs. 54.75±1.99 days) were significantly (P<0.05) reduced while the conception rate (71.43 vs. 28.57 %) was improved in bypass supplemented postpartum cows. Milk yield (11.45±0.36 vs. 9.18±0.41 kg/day) and milk fat % (5.47±0.12 vs. 5.05±0.14 %) improved significantly in bypass fat supplemented postpartum cows. Hence, it can be concluded that bypass fat supplementation @50g/day/h had no beneficial effect on onset of puberty in heifers; however supplementation of bypass fat @10g/kg milk yield/day/cow during early lactation significantly improved the milk production, induced early onset of post-partum estrus and improved the conception rate in dairy cows.