Studies On Trace Element Lick Block Of Grazing Sheep And Feeding Effects

Microelement surplus-deficit of Xinjiang fine wool sheep ewes in different seasons were studied in natural grassland of middle zone which lies on the northern slope of Tianshan Mountains.The rations of composite microelement were made according to feeding standard of ewes and implied in the feeding experiments.A new microelement-salt-molasses-block was developed on base of the experiment for Xinjiang fine wool sheep in this zone.The research results as follows:1 The daily microelement intake of grazing sheep was measured by gauze mask and mixed sample of edible forage which was made following the grazed ewes.Comparing with nutrition/nutrient requirements of sheep,daily intake of Fe,Mn,Co could meet the need of ewes and Zn was serious deficient(lacking up to 16%～82%) in grazed sheep except pregnancy in July and August,especially during the early lactation ewes only could get 17.8% from pasture.Daily intake by sheep could not get to a sufficient number of Cu and Se,the lack of Cu reached 55%～59%during the late pregnancy and early lactation,and the lack of Se reached 6%～52%during the whole year.2 Additive premix formula was designed,which was composed of CuSO₄·5H₂O 0.4%,FeSO₄·7H₂O 2.4%,MnSO₄·H₂O 1.5%,ZnSO₄·7H₂O 3.0%,premixed minor (KI,CoCl,Na₂SeO₃) 1.6%,stone powder 90.1%,and its feeding effect was tested by feeding experiments with 209 young ewe.The results showed that:weight gain(22.65±4.06kg)and daily gain(108±2.25g)of experiment group were significant higher than weight gain(11.15±4.18kg)and daily gain(53±3.23g)of control group(P<0.01),significantly increased wool growth,fine wool ratio and lamb birth weight(P<0.05),significantly improved survival rate of lamb and reproductive rate of ewes(P<0.01).3 Microelement-salt-molasses-block has been made into cubic of 15cm×15cm×7.5cm by 50T impact pressure.The best composition of the formula was selected through optimizing tests.The formulation of microelement-salt-molasses-block was trace-mineral premix 8%, stone powder 5%,salt 66%,bentonite 9%and molasses 12%.The Hardness and anti-wet property are well after dried in 9 days at room temperature.Feeding experiments were done with young ewes and adult ewes for 60 days.Daily intake of block was 12.31 g for young ewes and 14.60 g for adult ewes which was as expected.The gain of weight(6.12kg) in experiment group were significantly higher than that(1.60kg) in control group(P<0.01). Compared with control group,ewe's wool length,withers height and body length in experiment group increased 0.60cm,1.17cm,and 1.53cm respectively(p<0.05).The block feeding experiments on adult ewes was done in the period of pre-mating to delivery.The result showed that Lamb birth weight(4.02±0.91 kg) in experiment group was significantly higher than that(3.81±0.86 kg) in control group(P<0.05).The number of weaned lamb,lamb survival rate and ewes breeding rate of experiment group were 64,94.1%and 128%,and that in control group was 54,81.8%and 108%(P <0.01).4 The microelement-salt-molasses-block could be popularized in feeding Xingjian wool sheep because it could increase economical benefit significantly.