Effect of pre- and post-partum feed supplementation on the productive and reproductive performance of grazing primiparous Brahman cows

This experiment studied the combined effect of pre- and post-calving feed s upplementation on the productive and reproductive performance of primiparou s Brahman cows. The animals were 4 years old (420 kg live weight) and pregn ant, and grazed rotationally on Stargrass (Cynodon nlemfuensis) pastures. S upplementation was given before and after (T1, n = 15), only before (T2, n = 15) or only after (T3, n = 16) calving, and there was an unsupplemented c ontrol (T4, n = 16). The supplement (1.5 kg/animal per day, 13.4 MJ digesti ble energy/kg dry matter and 20% crude protein) was given for 45 days befor e and/or after calving. Changes in body weight and body condition score and the productive behaviour of the calves were similar (p >0.05) among treatm ents. The concentration of urea in the plasma was low in the control group (T4) before and after calving. The animals in all the groups had a poor rep roductive performance. The percentage of cows in oestrus was higher (p <0.0 5) in T1 (73.3%) than in T3 (37.5%). The interval from calving to conceptio n (148.7 +/- 53.7 days) and the pregnancy rate (48.5%) were similar (p >0.0 5) among the treatments. The level of supplementation offered before and/or after calving did not improve the pregnancy rate.