Effect of season on reproduction in west African Dwarf Bucks

This study was conducted to determine effects of season on some reproductive parameters of WAD bucks. Nine apparently healthy WAD bucks, aged between 18 and 24 months and weighing 8-15 Kg, were used to evaluate the effect of seasonal variations on Live-Weight (LW), Rectal Temperature (RT) and Scrotal Circumference (SC) between January and December, 2013. Semen was collected monthly by electro-ejaculation method and evaluated for spermiogram using standard techniques. Results were compared between and within groups using analysis of variance for repeated measures. Values are significant at p ˂ 0.05. Seasonal variation significantly (p ˂ 0.05) affected RT and SC except total sperm morphological abnormalities. Means for the total sperm morphological abnormalities were 7.42 ± 3.21% (late dry), 3.42 ± 0.36% (early rainy), 6.33 ± 0.33% (late rainy) and 7.25 ± 1.18% (early dry). The total morphologically abnormal spermatozoa reported for the seasonal study was 6.10%. It was thus concluded that seasons does not have significant effect on the spermiogram of WAD buck, however, they appeared to be most fertile during the early and late rainy seasons and least potentially fertile during early and late dry seasons.Keywords: Spermiogram, Season, Buck, Rectal temperature, Reproductio

The effect of some environmental and disease factors on testicular and epididymal functions of zebu bulls and their friesian crosses. The influence of season on ejaculate characteristic on A.I. bulls

The study was conducted to determine the influence of season on ejaculate characteristics and semen quality of artificial insemination bulls at NAPRI i.e bulls made up of charolis, Bunaji, Sokoto Gudali, Friesian and FRx Bunaji bulls, over a 2 year period. Semen was collected twice weekly and evaluated for volume, colour, PH concentration, motility, presence or absence of foreign materials, live-dead counts and sperm abnormalities. While there were no significant seasonal differences in percentage sperm motility (P>0.05), semen volume, sperm concentrations, morphological sperm defects and sperm live-dead counts were significantly influenced by season (

Fertility in Zebu cattle (Bos indicus) after prostaglandin administration and artificial insemination

A total of 137 cycling Zebu cows, each receiving a single dose of prostaglandin PGF 2a were used in an oestrus synchronization programme on three different farms. Of the cows on the three farms, 60.6 and 90.5 percent showed over oestrus and luteolysis, respectively. Pregnancy rate to fixed time inseminations following single injection of PGF 2a was 61.4 percent for farm 1, significantly higher than the values of 45.7 and 46.9 percent for farms 2 and 3, respectively. The pregnancy rates to second service of rebred cows were 53.3, 50.0 and 50.0 percent for the three farms, respectively, with no significant differences between each. Fertility classification of the cows based on progesterone (P4) concentration showed that 6.6 percent of cows on the three farms were incorrectly diagnosed as having corpora lutea; 2.9 percent of them had incomplete luteolysis and 5.1 percent may have lost their embryos between days 21 and 45 post-insemination. The pregnancy rate was 10 percent higher in the rainy season than in the dry season. Cows with body condition scores of 3 and 4 had a higher overall pregnancy rates than those with a body condition score of 2. The findings of this study further confirm the luteolytic efficacy of prostaglandin in inducing oestrus in Zebu cattle and indicate that the nutritional status of the cows must be satisfactory before embarking on oestrus synchronization programmes