Reproductive performance of Zebu heifers grazing on African Stargrass (Cynodon nlemfuensis) pastures, with or without access to Arachis pintoi protein banks in the humid tropics of Costa Rica

This study investigated the effect of grazing on African Stargrass (Cynodon nlemfuensis) pastures, with or without access to Arachis pintoi protein ba nks, on the reproductive performance of 36 Zebu heifers in the humid tropic s of Costa Rica. The animals were divided randomly into one of two treatmen t groups: Group 1, grass alone and Group 2, grass-legume. The live weight c hanges were significantly different (P < 0.05) between treatments in the se cond, 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 aff ected 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 mont h of birth of the heifers. Body weight at puberty and conception were affec ted significantly (P < 0.05) by the different pastures, however, these trai ts were not significantly (P > 0.05) affected by the month of birth of the heifers and number of parturition of their mothers.