Effects of Different Birth Season and Age of Weaning on Body Weight Gain and Blood Constituents of Goat Kids

• Main Authors: Ting Yen, 嚴婷
• Other Authors: Huo-Cheng Peh
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/61458449840951787105

碩士 === 國立中興大學 === 畜產學系 === 94 === This study has two purposes: the first is to examine the effect of birth season on growth of goat kids by comparing the feeding intakes, average body weight gain and blood constituents in goat kids born out of birth season using artificial controlled photoperiod mating in anestrus season and those born in birth season during the natural photoperiod. The second is to examine the effect of weaning at the 7th or the 9th week on the average body weight gain and blood constituents of goat kids; then to compare the effect of both different birth season and weaning age together. Seventeen kids born between August and October and twenty kids born between December and June were used in this experiment. During the experimental period, intake of water, milk replacer, concentrate and alfafa hay, and also the body weight of kids at 1-13 weeks of age were recorded in order to calculate body weight gain and feed efficiency. Blood samples were collected weekly from 6 to 13 weeks of age to analyze packed cell volume (PCV), the concentration of serum total protein, sodium, potassium and chloride. The serum protein bands of kids at 8 and 13 weeks of age were separated and quantified by agarose electrophoresis. The result shows that the higher average birth weight of kids born in the birth season, where the average birth weight was 3.27 kg; whereas those born out of the birth season was 2.67 kg ( P < 0.01), but there was no significant difference after the 5th week. Body weight gain of kids born in the birth season was higher than those born out of the birth season at 5, 6 and 7 weeks of age (P < 0.05). The PCV of kids born out of birth season was higher than those born in the birth season at 6, 9, 10, 11 and 13 weeks of age (P < 0.05). The concentration of serum total protein, γ-globulin and chloride of kids born in the birth season was higher than those born out of the birth season at 13 weeks of age (P < 0.05). The concentration of serum albumin, sodium and potassium, and A/G ratio of kids born out of the birth season was higher than those born in the birth season. In the different weaning age experiment, the average body weight of the kids weaned at 7 weeks of age was lower than these of the kids weaned at 9 weeks (P < 0.05) at 8 weeks of age. However, the body weight gain of kids weaned at 9 weeks was higher than that of those weaned at 7 weeks of age at both 7 and 8 weeks of age (P < 0.01). The PCV of kids weaned at 9 weeks was higher than those of 7 weeks at 10 and 11 weeks of age (P < 0.05). There was no significant difference of concentration of serum total protein, sodium and potassium between 7 and 9 week weaned kids. At 8 weeks of age, the concentration of chloride of kids weaned at 7 weeks was higher than those at 9 weeks (P < 0.05). In the kids weaned at 7 weeks, body weight, body weight gain, PCV and serum sodium concentration of kids born out of the birth season was higher than of those born in the birth season (P < 0.05). In the kids weaned at 9 weeks, the concentration of serum chloride of those born in the birth season was higher than those born out of the birth season (P < 0.05). In conclusion, kids born out of the birth season due to artificial controlled photoperiod mating in anestrus season are born lighter, but this does not affect the growth of kids. Growth performance and blood constituents of kids weaned at 7 weeks of age are no different from those weaned at 9 weeks, and the effect of different weaning age on kids born out of the birth season seems less than those born in the birth season. So artificial controlled photoperiod mating, and weaning kids somewhat ahead of age are both feasible methods of management.