Animal, Acqucture and Range Science Collection

Permanent URI for this collectionhttp://10.10.97.169:4000/handle/123456789/34

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Browsing Animal, Acqucture and Range Science Collection by Subject "Animal management"

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    Productive and reproductive performance of Tanzanian indigenous goats and their crosses with kamorai and boer
    (Sokoine University of Agriculture, 1992) Abunie, Berhanu Belay
    A study was conducted to compare genetic and non-genetic factors affecting growth and reproductive performance of Kamorai x Small East African (SEA), Boer x SEA and SEA using records kept at Department of Animal Science and Production from 1972 to 1989. In addition. Changes in body measurements and mortality rates were studied. Birth weight and weaning weight were significantly (P<0.05) affected by genetic groupr with Kamorai x SEA and Boer x SEA having higher values, respectively. Males were heavier than females in birth weight. Birth type and period of birth had significant (P<0.01 and P<0.001z respectively) effect on both birth weight and weaning weight. Effects of genetic group, sex and birth type on weight at 52 and 72 weeks and preweaning and postweaning growth rates was small and non- significant. There were genetic group differences in body measurements at certain ages.Body weight could be best predicted by the following Equation Y wherez Y -17.91 + 0.50Xi + 0.15X2 + 0.21X3 + 0.19X4 Predicted body weight (kg)z Xx width at the hind quarter X2 = body lengthz X3 = height a*t the wither and heart girth in cm. Age at first kidding ranged from 638 to 984 days and kidding interval ranged from 293 to 419 days. Age at first kidding was significantly (P<0.001) influenced by period of birth. Period of kidding as well as season of previous kidding affected kidding interval significantly (P< 0.01z P< 0.05, respectively).Overall mortality rate was 40.6% and 25.7% preweaning and postweaning periodz respectively. For Animals with birth weights of less than 1 • 5 kg and birth weights greater than 2.6 kg had the highest (57.9%) and lowest (29.8%)preweaning mortality rates, respectively. Twins exhibited highest (48.3% Vs 38.5%) preweaning mortality rate compared to singles. Lowest preweaning mortality (26.7%) occurred in period 1 (1972-1974). It can be concluded that the non-genetic factors especially period and season of birth were the main source of variation in postweaning growth traitsz performance and mortality rates. Reproductive There was no much gain achieved by crossing SEA goats with Kamoral and Boer. This was due to irregularity of management: in terms of nutrition and diseases control for the crosses which probably hindered them not to express their genetic potential.