Evaluation of Some Litter Traits and Heritability Estimates of Nigerian Indigenous Pigs

Cumulative litter records of 1494 progeny from 257 litters produced by 30 sires and 87 sows of Nigerian indigenous pigs (NIP) from the Swine Unit of Obafemi Awolowo University Teaching and Research Farm for a period of fourteen years (1977-1990) were used for this study. Data were analysed with the use of SAS (1997), litter trait means and their heritability were estimated with the use of variance component analysis. Results showed that, mean birth weight and weaning weight were 0.93 ± 0.02 kg, and 4.03 ± 0.55 kg respectively, and the litter weights at birth and weaning were 5.44 ± 0.12 kg and 23.39 ± 0.55 kg. The mean litter sizes at birth and at weaning were 5.82 ± 0.11 and 5.53 ± 0.11 respectively. The heritability estimates were 0.00 ± 0.04 for litter size at weaning and 0.37 ± 0.12 for weaning weight. Others were 0.36 ± 0.09, 0.29 ± 0.07, 0.24 ± 0.07 and 0.27 ± 0.07 for birth weight, litter birth weight, litter size at birth and litter weaning weight respectively. It was concluded that individual selection may be appropriate for genetic improvement of birth weight and weaning weight while family selection may be effective for litter birth weight, litter size at birth and litter weaning weight for the NIP

Genetic parameters and factors affecting reproductive performance in White Fulani cattle in southern Nigeria

Data on reproductive performance of the White Fulani (Bunaji) cattle in Southern Nigeria were analysed. Age at first calving, first and overall calving intervals averaged 4.03± 0.43 years, 436.19±9.32 and 420.98± 4.11 days respectively. The year of birth significantly affected age at first calving and calving interval (P < 0.01) but the season of birth had significant effect only on calving interval (P < 0.05). In addition the age of the dam also affected the calving interval (P < 0.05) but the sex of the calf nursed had no effect. Heritability estimates from half-sib analysis were 0.01± 0.03, 0.26±0.10 and 0.28±0.08 respectively for age at first calving, first and overall calving intervals. Low repeatability estimates were obtained for calving intervals