A Survey Of Cobalt Related Vitamin B12 Deficiency In Common Breeds Of Goats In Small Farming Communities Of The Rift Valley Of Kenya
A survey was carried out in order to find out (a) the prevalence of cobalt-related vitamin B12 deficiency in goats, (b) the effect of the deficiency on body condition and reproductive performance and (c) to describe the management practices of the farmers in the area and see how they predispose the goats to Vit. B12 deficiency. The survey was conducted in small farming communities of the endemically cobalt deficient area of the Rift Valley of Kenya. The survey area was divided into ten clusters each with 80 female goats. Approximately 800 female goats owned by small scale farmers were used in the study for determination of management practices and reproductive performance. Sixteen to twenty female goats in each cluster were used for body condition determinations and blood sampling for the analysis of, serum Vit. B12, hematology and blood qlucose. Goats were found to have a wide range of serum Vit. B1 2 levels, from 20.2 pg/ml to 937.5 pg/ml. The overall mean serum 81 2 .concentration was 205.5±9.37 pg/ml. Only 22 (10.1 %) out of 218 goats had serum Vit. 812 levels higher than 370 pg/ml which is considered adequate for sheep. The rest 196 (89.5%) goats had serum Vit. B12 levels less than 370 pg/ml. Of these, 122 (56.4%) .had serum Vit. B12 levels less than 180 pg/ml, the deficiency level in sheep while 74 or 33.5% of the goats had Vit. B12 levels in the marginal deficiency range for sheep, 180-370pg/ml. The mean serum Vit. B1 2 levels of the goats which received mineral supplements was 385.9±26.16 pg/ml. This was significantly different (P< 0.001) from the mean of 136.2±8.59 pg/ml. for the goats were not given mineral supplements. Cases of overt anaemia were found in every farm and cluster as demonstrated by RBC counts, Hb concentration, and haematocrit levels which were below the lower limit of the normal range for goats. Very low reproductive and weaning rates were found throughout the region of study. Cluster mean reproductive rates ranged from 0.6 kids per doe per year to 1.4 kids per doe per year and were far below the expected 2 kids per doe per year. Except one cluster which had comparatively better management, all the other clusters mean reproductive rates were <1.0 kid per doe per year. The weaning rates ranged from as low as 0.4 to 0.9 weaners, per doe per year. It is concluded that cobalt deficiency is widespread in goats in the study area. The deficiency is characteristically r marginal with many goats tending towards the clinical form. The clinical form is demonstrated by the prevalent anaemia, very low reproductive performance, poor body conditions, in some cases severe unthriftness and a tendency towards low blood glucose levels especially when goats are left to rely on pasture cobalt alone. The incidence of occurrence of cobalt deficiency in the area is reduced by free grazing and mineral supplementation. It is recommended that effective control would require very strict management measures. This can be achieved through adequate extension advice particularly to the small scale farmers in the cobalt deficient areas.