Abstract
This study investigated the effect of grazing on African Stargrass (Cynodon nlemfuensis) pastures, with or without access to Arachis pintoi protein banks, on the reproductive performance of 36 Zebu heifers in the humid tropics of Costa Rica. The animals were divided randomly into one of two treatment groups: Group 1, grass alone and Group 2, grass-legume. The live weight changes were significantly different (P < 0.05) between treatments in the second, sixth, and ninth month. Age at puberty in the Group 1 was 752 ± 41 days and 759 ± 51 kg (P > 0.05) for Group 2. Onset of puberty was not affected significantly (P > 0.05) by the treatments and number of parturition of their mothers. However, month of birth of the heifers (P < 0.05) had an effect. Age at conception was affected significantly (P < 0.05) by the month of birth of the heifers. Body weight at puberty and conception were affected significantly (P < 0.05) by the different pastures, however, these traits were not significantly (P > 0.05) affected by the month of birth of the heifers and number of parturition of their mothers.
