Mitochondrial DNA variation of indigenous goats in Narok and Isiolo counties of Kenya.

Phylogenetic relationships among and genetic variability within 60 goats from two different indigenous breeds in Narok and Isiolo counties in Kenya and 22 published goat samples were analysed using mitochondrial control region sequences. The results showed that there were 54 polymorphic sites in a 481-bp sequence and 29 haplotypes were determined. The mean haplotype diversity and nucleotide diversity were 0.981 ± 0.006 and 0.019 ± 0.001, respectively. The phylogenetic analysis in combination with goat haplogroup reference sequences from GenBank showed that all goat sequences were clustered into two haplogroups (A and G), of which haplogroup A was the commonest in the two populations. A very high percentage (99.90%) of the genetic variation was distributed within the regions, and a smaller percentage (0.10%) distributed among regions as revealed by the analysis of molecular variance (amova). This amova results showed that the divergence between regions was not statistically significant. We concluded that the high levels of intrapopulation diversity in Isiolo and Narok goats and the weak phylogeographic structuring suggested that there existed strong gene flow among goat populations probably caused by extensive transportation of goats in history.

Use of test-day records to predict first lactation 305-day milk yield using artificial neural network in Kenyan Holstein-Friesian dairy cows.

The study is focused on the capability of artificial neural networks (ANNs) to predict next month and first lactation 305-day milk yields (FLMY305) of Kenyan Holstein-Friesian (KHF) dairy cows based on a few available test days (TD) records in early lactation. The developed model was compared with multiple linear regressions (MLR). A total of 39,034 first parity TD records of KHF dairy cows collected over 102 herds were analyzed. Different ANNs were modeled and the best performing number of hidden layers and neurons and training algorithms retained. The best ANN model had one hidden layer of logistic transfer function for all models, but hidden nodes varied from 2 to 7. The R (2) value for ANNs for training, validation, and test data were consistently high showing that the models captured the features accurately. The R (2), r, and root mean square were consistently superior for ANN than MLR but significantly different (p > 0.05). The prediction equation with four variables, i.e., first, second, third, and fourth TD milk yield, gave adequate accuracy (79.0%) in estimating the FLMY305 from TD yield. It emerges from this study that the ANN model can be an alternative for prediction of FLMY305 and monthly TD in KHF.

Thyroid hormones and metabolic rate during induction of Vitamin B12 deficiency in goats.

Vitamin B12 deficiency was induced in 15 small East African goats by feeding cobalt deficient Chloris gayana hay (containing 0.02 mg of Co/kg dry matter) over a 25 week experimental period. Cobalt was supplemented as an oral drench to supply 0.3 g of Co/goat/week to 15 treated goats. At intervals of 3-4 weeks, serum concentrations of Vitamin B12 , total thyroxine (TT4), free tetra-iodothyronine (FT4) and free tri-iodothyronine (FT3) were determined by radioimmunoassay, while the rate of resting metabolism was determined by measuring the goats' rate of oxygen consumption. Serum Vitamin B12 concentration was significantly higher (p<0.01) in cobalt-treated (289.6 +/- 40.76 pg/ml) than in control (142.8 +/- 28.27 pg/ml) goats. The mean serum TT4 concentration was significantly (p<0.01) higher in control (59.0 +/- 1.70 nmol/l) than in cobalt-treated (51.6 +/- 2.45 nmol/l) goats. However, the levels of FT4, FT3 and the rate of resting metabolism were unaffected by the goats' cobalt status. Furthermore, the goats did not lose weight or become anaemic.

Changes in serum levels of vitamin B12, feed intake, liveweight and hematological parameters in cobalt deficient small east African goats.

Thirty short-horned East African goats were divided into two groups (treatments 1 and 2) consisting of fifteen goats each. All the goats were fed on a cobalt deficient diet containing 0.02 mg Co/kg of dry matter for a period of twenty three weeks. Goats in treatment 1 were supplemented with an oral cobalt chloride drench. Cobalt deficiency developed in goats in treatment 2 after ten weeks when their serum vitamin B12 concentration fell below 200-250 pg/ml. Between the third and the twenty-third weeks of the experiment, the mean serum concentration of vitamin B12 was significantly (P < 0.01) higher in cobalt supplemented (289.6 +/- 40.76 pg/ml) than deficient (142.8 +/- 28.27 pg/ml) goats. Total dry matter intake, intake per metabolic body weight and liveweight changes were not significantly (P > 0.05) different between goats in the two treatments. Although packed cell volume, hemoglobin concentration, and erythrocyte count were significantly (P < 0.05) higher in cobalt adequate than deficient goats, these blood parameters were within the normal range for goats. It is suggested that although serum vitamin B12 standard for sheep is applied for goats, the latter species is likely to be more resistant to low dietary cobalt intake than sheep.