Effect of non genetic factors on productive traits of Black Bengal goats

Abstract

Accumulated five years data on 197 kids of 15 Black Bengal bucks in the nucleus breeding flock of Black Bengal goats were analyzed for the study of production traits. The traits considered were birth weight, weight at every 3-month interval up to 12-month, semen characteristics and milk yield. Semen parameters were evaluated from 450 ejaculates of 15 Black Bengal bucks collected twice a week by artificial vagina method and daily milk yield of Black Bengal goats were estimated from the analysis of 57 lactation records of 30 does. The significance of fixed effects sex of kid, parity, litter size, season, age, body weight and scrotal circumferance were analyzed using least-squares analyses of variance of the general linear model (GLM) procedure of the Statistical Analysis System (SAS, 1998). Least-squares means for body weights at birth, 3, 6, 9 and 12-month of age were 1.3, 4.8, 8.0, 11.1 and 14.0 kg, respectively. Body weights at 3, 6, 9 and 12-month of age except at birth were affected by the sex of kids (p<0.05). Type of birth and parity of dam had the significant affect (p<0.05) on birth weight, whereas season of birth had significant (p<0.05) effect on the body weight. The least-squares means of semen volume (ml/ejaculate), sperm concentration (10 9 /ml), mass motility (%), live spermatozoa (%) and normal spermatozoa (%) were 0.5, 2.4, 80.0, 86.5 and 89.3, respectively. Age of bucks had significant (p<0.01) affect on semen volume, sperm concentration. Body weight had a significant (p<0.05) effect on semen volume only. Least-squares mean of daily milk yield was 379.9 lit.. Milk yields was significantly (p<0.01) affected by litter size and season of kidding. It is suggested that nongenetic factors should be adopted as a technique for improving the productive traits.

Effect of Fixed Factors and Estimation of Genetic Parameters of Growth Traits for Mountain Kids

“…Variation in body weight of kids in different breeds could be attributed to the genetic content of parents due to their affect by the doe breed (20) and sire breed (40). Body weights of kids revealed in this study lay within the range (1.09-4.42 kg) for BWT, (4.8-23.0 kg) for WWT, and (7.35-26.72 kg) for WT6M which found by earlier studies conducted at several countries using different breeds (5,13,21,26,28,29,30,31,33,34,35,38,41,46,55,57). Although there was no significant effect for age of doe on all studied traits (Table 2), however with using Scheffe's test to diagnosing the significant differences between the levels of age of doe, it appears that does aging 3.5 years gives kids having significantly higher BWT, while the differences among the kids born from does with different ages were not significant in their WWT and WT6M (Table 1).…”

“…While other studies didn't noticed the significant effect of type of birth on birth weight of kids (13,55). At weaning, several studies showed the same effect of type of birth as in this study, where differences between singles and twins were not significant (3,32,36,38,55). Whereas, Rashidi et al (46), Hermiz et al (27 and 29), Al-Barzinji (2), and Tyagi et al (57) found that type of birth has significant impact on WWT.…”

“…Whereas, Rashidi et al (46), Hermiz et al (27 and 29), Al-Barzinji (2), and Tyagi et al (57) found that type of birth has significant impact on WWT. The non-significant effect of type of birth on kids body weight at 6 month were showed by many researchers (27,29,38,55). On other hand, Hermiz et al (26) and Tyagi et al (57) reported that type of birth affect WT6M significantly.…”

“…Such differences in the birth weight could be due to the characteristic that weight of cotyledons in males were 10.5 % heavier than females (47), and the differences in WWT and WT6M could be attributed to hormonal differences between them and their resultant effects on growth (43). It is generally accepted by many researchers that male kids were greater than female kids significantly in their body weights at birth (5,12,13,17,21,25,27,29,33,41,42,46,57); and at weaning (2,13,17,27,29,33,41,46); as well at 6 month old (5,24,27,29,38,41,46,55). On the other hand, many researchers showed that the differences between male and female kids were not significant at birth (26,36); and at weaning (3,5,9,28,36); as well at 6 months of age (3,28).…”

Non-genetic factors affecting pre-weaning growth and morphometric traits in Assam Hill goat

“…However, a significant effect of season of birth on both the traits was reported by Mahal et al . [16] in Black Bengal goats.…”