The Study And Application Of Tan Sheep Lamb Breeding Technology

Tan sheep is an excellent local sheep breed with both meat and wool.It is famous for its high-quality fur and lamb meat.However,Tan sheep has disadvantages such as slow growth rate and low reproduction rate,which restricts the further development of Tan sheep industry.Lamb breeding technology,as an important part of the efficient breeding technology system,promotes the growth and development of lambs,improves the body condition of lambs,improves the survival rate and resistance of lambs,and realizes early weaning of lambs by strengthening lamb feeding management and early supplementary feeding.In this study,Tan Sheep lambs were selected as test subjects.By analyzing the effects of different breeding schemes on growth performance,blood biochemistry,digestive tract development and rumen microflora,economic and effective breeding schemes for Tan sheep lambs were selected.The research contents and obtained results are as follows:（1）Preliminary screening of Lamb breeding programA total of 180 single Tan lambs with good homogeneity and similar birth time were randomly divided into 6 groups.The control group was not treated;Test groupⅠwas fed granules freely from10 d;Test groupⅡwas supplemented with granule feed from 10 d（ewe and lambs were separated from 9 am to 5 pm every day）.Test groupⅢwas supplemented with granule feed from 15 d.Test groupⅣwas given free mixed feed（80%granule feed+20%alfalfa meal）from the 15 d.Test groupⅤwas supplemented with mixed compound from 15 d.Weaning can be done if the body weight reaches 12 kg at 60 days,otherwise continue breeding until the body weight reaches 12 kg.The changes of daily feed intake and body weight of lambs in each group were recorded.The results showed that the body weight of all lambs reached more than 12 kg at 60 days,and the body weight of all test groups was significantly higher than that of the control group（P<0.05）;The daily weight gain of lambs in test group during 45～60 days was significantly higher than that in control group（P<0.05）.Based on feed intake and daily gain of lambs,the economic gain of the supplementary feeding scheme was calculated,and the results showed that the treatment of test groupⅣbrought the greatest benefit.（2）Optimization of breeding program for lambA total of 100 Tan lambs with good homogeneity and similar birth time were randomly divided into 5 groups,with 20 lambs in each group（14 single lambs and 6 twin lambs）.The control group was not treated;Lambs of test group I were free to eat mixed feed from 10 d;Group II lamb during 10～14 d free feed intake mixture,started 15 d grille supplementary feeding mixture;Lambs of test groupⅢwere free to eat mixed feed at 15 d.Lambs of the test groupⅣwere supplemented with mixed feed at separate stalls on the 15 d.Weaning can be done if the body weight reaches 12 kg at 60 days,otherwise continue breeding until the body weight reaches 12 kg.（1）The daily feed intake,body weight and body size changes of lambs in each group were recorded,and the daily weight gain and economic gain were calculated.The results showed that the growth rate of each body size index of the lambs in the testal group was higher than that in the control group.The weaning weight of the lambs in the testal group was 45 days,while that of the lambs in the control group was 65 days;Body weight and daily gain of lambs in testal group were significantly higher than those in control group（P<0.05）.The testal groupⅠhad the highest daily gain and the highest gain was 167 yuan.（2）Blood oxidation related indicators of lambs at 9 d,12 d,15 d,18 d,21 d were detected.The results showed that the activities of serum antioxidant enzymes（SOD,CAT,GSH-PX）and the contents of oxidation products（MDA,H₂O₂）in the testal group were significantly higher than those in the control group（P<0.05）.（3）Blood biochemical indexes were detected at 15 d,30d,45 d and 60 d.The results showed that the serum TP,TG,GLU,GH and IGF-1 of lambs were maintained at relatively stable levels.On day 15,the serum ALB level of lambs in testal groupsⅠandⅡwas significantly higher than that in control group（P<0.05）.The serum UREA level of the testal group was significantly higher than that of the control group at 45 days and60 days（P<0.05）,while the serum TC content of the testal group was significantly lower than that of the control group at 30 days and 45 days（P<0.05）.（4）Three lambs in testal group I,testal group II and control group with better weight gain and economic gain were selected to detect ruminal fermentation parameters.The results showed that there were no significant differences in rumen p H and NH₃-N concentration among the three groups（P>0.05）;The rumen TVFA and the ratio of acetic acid to propionate in testal group I were higher than those in control group and testal group II.There was no significant difference in the proportion of various VFA in TVFA among the three groups（P>0.05）.（5）Three lambs in testal group I,testal group II and control group with better weight gain and economic gain were selected.Small intestinal tissues were collected to analyze the villus length and crypt depth of duodenum,jejunum and ileum.The results showed that the villus length of ileum and jejunum and the ratio of villus length to crypt depth（V/C）in testal groupsⅠandⅡwere significantly higher than those in control group（P<0.05）.The depth of duodenal crypt in testal groups I and II was significantly lower than that in control group（P<0.05）.（6）Four lambs of testal group I and four lambs of control group with better economic gain were selected for rumen microflora analysis.The results showed that there were no significant differences in ruminal microbial richness and diversity between the two groups（P>0.05）;At the phylum level,Firmicutes was dominant,followed by Bacteroidetes in both control group and testal groupⅠ;Prevotella was the dominant microorganism at the genus level in both control group and testal groupⅠ.To determine the distribution of taxa between the two groups,Lef Se analysis was performed and revealed that the dominant flora in the control group was Rikenellaceae,Selenomonadaceae,UCG-001,Corynebacterium,Corynebacteriaceae;However,the dominant flora in testal groupⅠwas Erysipelatoclostridiaceae,Erysipelotrichales,Atopobium,Anaerovoracaceae,Sharpea,Atopobiaceae.（3）large group application test of optimized cultivation schemeIn the spring of 2022,132 lambs（83 singleton and 49 twin lambs）were randomly selected for 0 d,15 d,30 d,45 d and 60 d body weight monitoring.The results showed that single lambs reached 12 kg at 45 days and twin lambs reached 12 kg at 66.61 days.The pre-weaning survival rate of lambs was increased from 86.11%to 94.45%in 2020～2022.Based on the above studies,it was concluded that the program of free feeding mixture（80%pellet feed+20%alfalfa meal）starting from day 10 was economical and practical,and the breeding effect was good.