Supplementation with urea and molasses and body weight, milk yield and onset of ovarian cyclicity in cows

Ten multiparous crossbred local Zebu cows were randomly divided into two nutritional groups (A and B) to determine the effect of urea-molasses-mineral block supplementation on body weight gain, milk production, and onset of ovarian cyclicity after calving. Both groups had farm rations daily, but the supplemented group (B) was provided with an additional diet daily of 250 g urea-molasses-mineral block. The cows in group A required 80-120 days (98.0 +- 6.7 days) until peak milk progesterone concentrations and 60-80 days (72.0 +- 3.8 days) were required for group B (p0.05). Group B needed a shorter period for expression of standing estrus (91-101 days; mean 96.2 +- 2.3 days) than group A [130-153 (141.6 +- 4.6) days; p0.01]. For groups A and B, body weight gain was 8.4 +- 3.4 kg and 18.4 +- 3.2 kg, respectively (p0.01). The average milk production of groups A and B were 3.3 +- 1.0 and 4.8 +- 1.6 L/day, respectively (p0.05). There was linear improvement in milk yield from day 60 postpartum up to day 90 of lactation in group B (supplemented). However, in group A, milk production decreased starting on day 40 after parturition.