Use of pymarc as a nitrogen source for grazing dairy calves

A study was conducted to determine optimal levels of pymarc inclusion as a protein supplement to Chloris gayana during the dry season. Forty Friesian dairy calves of 65 ± 7 kg weight, 20 each of males and females, were randomly allocated to a 10-diet treatment in a completely randomized design in a factorial arrangement. The treatment diets were: control, 7.5, 15, 22.5, and 30 g DM/kg W^0.75 pymarc, with (PBM) or without molasses (PB). Live weight gains, intake, diet digestibility, rumen pH, and rumen ammonia nitrogen were assessed in the 60-day experiment. Herbage intake did not differ (P > 0.05) among the treatments. Total intake was in the range of 2072–2636 g/day, diet digestibility 565–582 g/kg, and ADG 157–330 g/day, and differed (P < 0.05) with supplementation. The results showed that rumen pH did not differ significantly (P > 0.05) between the treatments, ranging between 6.97 and 7.17. Rumen NH₃–N control groups PB and PBM had 109.9 and 106.5 mg/l, respectively, while those supplemented increased linearly (P < 0.05) to 166.5 and 177.14 mg/l, respectively, at the highest level of supplementation. The nutritional profile and potential degradation level of pymarc as well as the performance of calves indicate the latent value as a supplement in providing nitrogen to poor-quality basal diets in the dry season.