The role of minerals in the growth and viability of Bunaji cattle raised under traditional management in central Nigeria

Abstract

About 400 Bunaji cattle from 11 herds at three sites namely, Kurmin Biri, Madaucbi and Ganawuri were used to study the productivity of cattle fed mineral  supplements under village conditlcns. Two herds at each site were allocated at random to each treatment. Mineral blocks containing 1 a% P and local salt licks  containing 96% NaCl ; which served as control were fed. Supplementation lasted three years. Mineral blocks were put out daily in the Kraals and taken in during  rains and when the animals went grazing. Births and disposals were recorded. Animals were weighed monthly using portable barlo electronic scales. Animals  grazed natural pasture and crop residues after harvest. Data were analysed using general linear models (GLM) procedure of SAS. Analysis were done for birth  weights up to 18 months. Models used for analysis involved the fixed effects of location,  herds nested within location. year and season of calving, parity, age of  dam and sex of  calf. The results showed that birth weights were significantly influenced by location  P<O.OS), year of birth (P<0.05) and mineral supplementation (P<0.05). The birth weights were 22.4 ± O.S3, 21.1 ± 0.42 and 18.2 ± 0.40 kg in Ganawuri~ Kurmin Biri and Madauchi respectively. Calves born in 1988  were significantly heavier than those born in 1989 and 1990 and weighed 21.1 ± 0.47, 19.8 ± 0.39 and 20.8 ± 0.48 kg in 1988, 1989 and 1990 respectively. The  mineral supplemented calves weighed 21.1 ± 0.38 and 19.9 ± 0.36  kg for phosphate and salt respectively. Using weight as a covariate, it was shown that the growth rate of P supplemented group was Nigerian Jourual of Animal Production 19(1992) significantly higher than the control group P<0.05) so that at 18 months  the mineral group weighed 165 kgt an improvement of 21%. Calving interval was influenced by location (P<0.05), year· or calving (P<0.01) but not significantly by  treatment (P>0.05).Calving intervals were !30 ± 62.9 and 503 ± 54.8 days for mineral and salt respectively. Cumulative mortality percentage of calves to 9 and 12 months were not significantly affected by mineral supplementation (P>0.05). These were 11.1 ± S.00 and 13.4 ± 5.31 and 17.4 ± S.06 and 24.0 ± 5.43 for mineral  and salt respectively. It is concluded that the provision of P-rich mineral blocks to agropastornl herds at strategic periods can improve the productivity of Bunaji  cattle.

Key words: Mineral supplementation, Bunaji cattle, growth, calf mortality, calving  interval, Central Nigeria.