Research On Utilization Of Calcium And Phosphorus In Alpine Merino Sheep And Principal Mineral Requirements Of Its Lamb

The Alpine Merino sheep is the new breed of fine-wool sheep that can adapte to the cold and arid ecological regions of the Qinghai-Tibet Plateau.And more,it has the stable genetic performance,strong resistance to adversity,and good wool production performance,but its nutritional requirements especial mineral are still not reported.Therefore,the present experiments were conducted to systematically study the characteristics of Ca and P utilization,and profile the distribution rule,and build the prediction models of principal mineral requirements for Alpine Merino lamb by the method of digestion and metabolism trial and comparative slaughter trial.Those researchs can help to provide data and technological support for Alpine Merino sheep Industry production.The research contents and results were as follows:1.The utilization characteristics of Ca and P of Alpine Merino sheep（1）The thirty-two Alpine Merino rams were randomly divided into two groups named the mating group and the non-mating group,and each of group was divided into ad libitum group（RAL）,80%ad libitum group（0.8RAL）,60%ad libitum group（0.6RAL）,40%ad libitum group（0.4 RAL）acording to feeding level.The results showed that the mating task had a significant effect on the apparent digestibility and utilization of Ca and P of Alpine Merino rams（P<0.05）.There were significant effctes on the content of Ca and P in feces,and digestible calcium and phosphorus（P<0.001）.and the interaction effects of mating task and feeding level on on the phosphorus intake and fecal phosphorus were significant（P<0.001）.（2）The thirty-two Alpine Merino growing sheep were selected,and each gender was divided into 4 groups according to the feeding level named ad libitum group（YAL）,80%ad libitum group（0.8 YAL）,60%ad libitum group（0.6 YAL）and 40%ad libitum group（0.4 YAL）.The results showed that:the gender and feeding level had significant influence on the content of fecal Ca and P（P<0.05）,and there was a significant interaction on the P intake and content of fecal Ca（P<0.05）.（3）The thirty-six Alpine Merino lambs were selected,and each gender was divided into 3 groups according to the feeding level named ad libitum group（FAL）,70%ad libitum group（0.7 AL）,40%ad libitum group（0.4 AL）.The results showed that there were significant gender and feeding level effects on Ca and P intake,fecal Ca and P content,digestible Ca and P（P<0.001）,and the interaction effects were significant on Ca intake and fecal Ca content（P<0.05）.2.Growth performance and distribution characteristics of principal minerals in Alpine Merino lambThere was no significant difference in the initial body weight between male and female lambs of Alpine Merino（P>0.05）.With the decreasing of feeding level,the dry matter intake,slaughter live weight,empty body weight and carcass weight of male and female lambs were decreased（P<0.001）,and the grade was FAL>0.7AL>0.4AL.With the increasing of lamb weight,there were significant differences in dry matter intake,slaughter live weight,empty body weight and carcass weight among the three groups[Initial ad libitum group（IAL）,Medium ad libitum group（MAL）and FAL)（P<0.001）.The slaughter rates for male lambs were no difference among IAL,MAL and FAL（P>0.05）,but its of MAL and FAL were greater than its of IAL for female lambs（P<0.05）.With the increasing of lambs weight,the mineral content of lamb’s muscle,skin and viscera were increased（P<0.05）,but there was no effect on the wool mineral content（P>0.05）.Ca and P are mainly distributed in bone,and Cu,Mn and Fe are higher in visceral tissue,and Zn are mainly distributed in muscle and bone.3.The prediction models of principal mineral requirements for Alpine Merino lambThe maintenance requirements of Ca,P,Mg,Cu,Mn,Zn and Fe for Alpine Merino male lamb of 20 to 45 kg body weight were recommonded 0.37 g/d,0.61 g/d,0.047 g/d,0.78 mg/d,0.052 mg/d,2.79 mg/d,and 13.24 mg/d,respectively.Those indexes for Alpine Merino female lamb were recommonded 0.42 g/d,0.57 g/d,0.034g/d,0.74 mg/d,0.07 mg/d,3.26 mg/d,and 6.71 mg/d,respectively.The prediction models of the net growth requirement of calcium(NRG_Ca),P（NRG_P）,Mg(NRG_Mg),Cu(NRG_Cu),Mn(NRG_Mn),Zn(NRG_Zn)and Fe(NRG_Fe)for Alpine Merino male lamb were as follow:NRG_Ca（g/kg EBW）=13.6095×EBW^-0.1938;NRG_P（g/kg EBW）=2.2710×EBW^0.1957;NRG_Mg（g/kg EBW）=0.7489×EBW^-0.1615;NRG_Cu（g/kg EBW）=0.7597×EBW^0.8598;NRG_Mn（g/kg EBW）=8.4440×EBW^-0.7115;NRG_Zn（g/kg EBW）=40.6585×EBW^-0.1554;NRG_Fe（g/kg EBW）=132.5829×EBW^-0.1913;EBW（kg）=-2.1631+0.9254BW（kg）.The prediction models of the net growth requirement of calcium(NRG_Ca),P（NRG_P）,Mg(NRG_Mg),Cu(NRG_Cu),Mn(NRG_Mn),Zn(NRG_Zn)and Fe(NRG_Fe)for Alpine Merino female lamb were as follow:NRG_Ca（g/kg EBW）=14.7320×EBW^-0.3587;NRG_P（g/kg EBW）=11.0635×EBW^-0.3419;NRG_Mg（g/kg EBW）=1.4300×EBW^-0.682;NRG_Cu（g/kg EBW）=7.4949×EBW^0.0707;NRG_Mn（g/kg EBW）=0.2859×EBW^0.6993;NRG_Zn（g/kg EBW）=79.9816×EBW^-0.5468;NRG_Fe（g/kg EBW）=162.7973×EBW^-0.3495;EBW（kg）=-2.2656+0.9575BW（kg）.In summary,there are differences in the utilization characteristics of Ca and P for Alpine Merino sheep during different physiological stages,under various feeding level or administratingmodes,and then the reasonable dierary supply of calcium and phosphorus is conducive to the performance of Alpine Merino sheep.Ca and P are mainly distributed in bone,and Cu,Mn and Fe are higher in visceral tissue,and Zn are mainly distributed in muscle and bone.Compared with other sheep breed,Alpine Merino lamb has higher net growth needs of Ca,P,Mg,Zn and Fe,and higher needs of Cu,but the maintenance needs of Ca,P,Mg,Cu,Zn and Fe are similar,and higher for Mn.Based on the prediction model of present study,the authors also recommended the needs of Ca,P,Mg,Cu,Mn,Zn and Fe for Alpine Merino male and female lamb as shown in Appendix Table1 and Table2.Hope those parameters to be verified and optimized in the follow-up study,and it will be helpful for the production performance of Alpine Merino lambs.