Document Type : Research Paper
Author
agriculture and natural resources research and education center of chaharmahal and bakhtiari
Abstract
This study was conducted to investigate the effect of increasing the length of the lighting in the early lactation on the milk production in native black goats, as well as the weight and weight gain of their kids. A total of 40 pregnant goats were randomly divided into the following two groups. group 1 (control): goats were exposed to the natural day length during lactation period. group 2: goats were exposed to the long days during the first 30 days of the lactation period. During the first month of lactation, the amount of milk produced was measured weekly. The blood samples were taken 20 days before kidding, at kidding, 15 and 30 days after kidding. The kids’ weight was measured at birth, at the ages of 7 days, 14 days, one month, two months and three months. The amount of milk suckled on the 7th, 14th, 21th and 28th days after birth in the second group was 6.9%, 9%, 6.9%, and 6.13% higher than in the control group, respectively (p<0.01). The milk composition was not affected by the experimental treatment (p>0.05). The level of prolactin hormone in the second group was 21 and 23% higher than control group at 15 and 30 days after kidding, respectively (p<0.01). At the age of 14 days, one, two and three months, the highest kids’ weight was observed in the second group (p<0.01). Additionally, weight gain in the kid of the second group was better than control group in all periods (p<0.01).
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