Application of Artificial Insemination in Selective Breeding of Native Beef Cattle in Wenzhou

[Objective]The paper was to improve the quality and growth rate of native yellow cattle in Wenzhou.[Method]Three groups of cattle were subjected to artificial insemination using frozen semen from Wagyu bull.The groups consisted of 20 native yellow cattle,20 Angus catle,and 20 Luxi yellow cattle.The heifers were subsequently evaluated for body size and body weight,and underwent treatment with estrus synchronization,artificial insemination,and early pregnancy diagnosis.[Result]The mean body size and body weight of native yellow cattle were found to be significantly lower than those of Angus cattle and Luxi yellow cattle(P<0.05).The estrus synchronization rate and mating rate of native yellow cattle were both 100%,while the corresponding rates for Angus cattle and Luxi yellow cattle were 90%and 95%,respectively.The ultrasound examination conducted on the 32m day following the mating revealed a distinct image of gestation sac,which,when considered alongside the findings of the rectal examination,may be indicative of pregnancy.The conception rates were 75%,72%,and 74%for native yllow cattle,Angus cattle,and Luxi yellow cattle,respectively.[Conclusion]The reproductive performance of native beef cattle is relatively superior.

Effects of different dietary energy and protein levels and sex on growth performance,carcass characteristics and meat quality of F1 Angus x Chinese Xiangxi yellow cattle

Background：The experiment evaluated the effect of nutrition levels and sex on the growth performance,carcass characteristics and meat quality of F1 Angus × Chinese Xiangxi yellow cattle.Methods：During the background period of 184 d,23 steers and 24 heifers were fed the same ration,then put into a2×2×2 factorial arrangement under two levels of- dietary energy（TON：70/80%DM）,protein（CP：11.9/14.3%DM）and sex（S：male/female） during the finishing phase of 146 d.The treatments were-（1） high energy/low protein（HELP）,（2） high energy/high protein（HEHP）,（3） low energy/low protein（LELP） and（4） low energy/high protein（LEHP）.Each treatment used 6 steers and 6 heifers,except for HELP- 5 steers and 6 heifers.Results：Growth rate and final carcass weight were unaffected by dietary energy and protein levels or by sex.Compared with the LE diet group,the HE group had significantly lower dry matter intake（DMI,6.76 vs.7.48 kg DM/d）,greater chest girth increments（46.1 vs.36.8 cm）,higher carcass fat（19.9 vs.16.3%） and intramuscular fat content（29.9 vs.22.8%DM）.The HE group also had improved yields of top and medium top grade commercial meat cuts（39.9 vs.36.5%）.The dressing percentage was higher for the HP group than the LP group（53.4 vs.54.9%）.Steers had a greater length increment（9.0 vs.8.3 cm）,but lower carcass fat content（16.8 vs.19.4%） than heifers.The meat quality traits（shear force value,drip loss,cooking loss and water holding capacity） were not affected by treatments or sex,averaging 3.14 kg,2.5,31.5 and 52.9%,respectively.The nutritive profiles（both fatty and amino acid composition） were not influenced by the energy or protein levels or by sex.Conclusions：The dietary energy and protein levels and sex significantly influenced the carcass characteristics and chemical composition of meat but not thegrowth performance,meat quality traits and nutritive profiles.