| In this research, 25 second-parity Gansu alpine fine wool sheep ewes and 29 lambs were selected as the research objects. The milk production of ewes from 2 to 70 days and the body weight of lambs were determined aiming to provide theoretical basis for the feeding management of ewes and early weaning technology of lambs of Gansu alpine fine wool sheep. This research included two experiments: Experiment 1: Research on lactation laws of Gansu alpine fine wool sheep from 2~75 days.To describe the lactation laws of Gansu alpine fine wool sheep systematically, 25 ewes were selected and divided into 25 repeats with one ewe in each repeat. The milk productions of ewes were calculated by analyzing the lamb weight before and after lactation. Lambs were fed by 5 times/day, 4 times/day, 3 times/day in 2~15 d, 15~30 d, 30~75 d, respectively. The regression equation of lactation curve was established. On the basis of accurate results, the lactation curve was fitted by Wood model. The results showed that:(1) The total milk yield of Gansu alpine fine wool sheep from 2 d to 75 d after delivery was 72.33±11.42 kg with an average daily milk yield of 977.37±154.31 g.(2) The lactation curve of Gansu alpine fine wool sheep after delivery from 2 d to 75 d was consistent with the Wood model.(3) The total milk yield of lactation of 10 labor-male-lamb ewes and 11 labor-female-lamb ewes from 2 d to 75 d after delivery were 76.95±11.02 kg and 68.12±10.52 kg, respectively. Average milk yield per day was 1039.90±148.87 g and 920.53±142.17 g, respectively. However, lamb sex had no significant effects on milk yield and lactation curve parameters(P>0.05).(4) Lambs were divided into two groups according to birth weight. From 2 d to 75 d after delivery, the total milk yield of ewes which delivered larger birth-weight lambs ewes were 74.169±13.431 kg, while those which delivered smaller birth-weight lambs were 70.649 ± 9.588 kg. Although total milk yields improved 4.98%, lamb birth weight had no significant effects on milk yield and lactation curve parameters(P>0.05).(5) The lactation curve of Gansu alpine fine wool sheep had characteristics as follows: rising fast in early lactation; peaking early and highly; decreasing fast in late lactation.(6) The milk yield of Gansu alpine fine wool sheep is relatively low after 75 d. Lamb can rely on grass and small amount of feeding pellets to meet its growth need. Experiment 2: Research on weight growth rules of Gansu alpine fine wool sheep lamb in lactation periodIn order to verify the possibility of early weaning lambs, the body weight of 29 lambs were measured accurately every day after birth. On the basis of the results, the cumulative growth curves, absolute growth curve and relative growth curve were analyzed to describe the weight growth rules of Gansu alpine fine wool sheep. The results indicated that:(1) The average birth weight of 29 Gansu alpine fine wool sheep was 3.994±0.727 kg and increased to 21.937±3.278 kg at 75 d. The body weight of lambs was increased by 17.943 kg with 249.3 g per day.(2) The cumulative growth of lambs was approximately linear. The weight of lambs and milk yield of ewes had strong positive correlation(r=0.988).(3) The absolute growth curve of lamb showed that the body weight of lamb increased rapidly from 1 to 10 days, increased steadily from 11 to 50 days, and fluctuated and decreased from 50 to 75 days.(4) The relative growth curve of lamb showed that the relative growth rate of lambs increased rapidly after born and peaked at 10 days. After that, it declined rapidly and then decreased gradually after 30 days.(5) According to the growth rules of Gansu alpine fine wool sheep, it’s feasible that lambs weaned early at 75 d.In summary, the lactation curve of Gansu alpine fine wool sheep had characteristics as follows: rising fast in early lactation; peaking early and highly; decreasing fast in late lactation, and the cumulative growth of lambs was approximately linear, which indicate that Gansu alpine fine wool sheep can be weaned early at 75 d. |
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