Purebreeding with sexed semen and crossbreeding with semen from double-muscled sires to improve beef production from dairy herds: Live and slaughter performances of crossbred calves

摘要

The use of sexed semen to produce purebred replacementheifers allows a large proportion of dairy cowsto be mated to beef sires, and quantitative and qualitativeimprovements to be made to beef productionfrom dairy herds. The major dairy and beef breeds areundergoing rapid genetic improvement as a result ofmore efficient selection methods, prompting a need toevaluate the meat production of crossbred beef × dairycattle produced using current genetics. As part of alarge project involving 125 commercial dairy farms, weevaluated the combined use of purebreeding with sexedsemen and crossbreeding with semen from beef sires,particularly double-muscled breeds. A survey of 1,530crossbred calves revealed that, whereas purebred dairycalves are destined almost exclusively for veal production,beef × dairy crossbred calves are also destined forbeef production after fattening on either the dairy farmof birth or by specialized fatteners. In veal production,compared with Belgian Blue–sired calves (taken as thereference), double-muscled INRA 95–sired calves had alighter slaughter weight (303 vs. 346 kg), but a greaterdressing percent (62.3 vs. 58.4%). Limousin (also knownas Limousine)–sired calves had a smaller average dailygain (1.26 vs. 1.34 kg/d), and lighter slaughter (314vs. 346 kg) and carcass weights (182 vs. 201 kg). Last,Simmental-sired calves had a similar growth rate, butlighter carcass weight (177 vs. 201 kg), smaller dressingpercentage (55.3 vs. 58.4%), and smaller muscularityscores (3.25 vs. 3.72). In the case of young bulls andheifers fattened on the dairy farm of birth, BelgianBlue–, Piemontese (also known as Piedmontese)-, andLimousin-sired calves performed similarly; the only exceptionwas that Piemontese-sired calves had a greaterdressing percentage. Belgian Blue– and Limousin-siredcalves performed similarly when fattened by specializedbeef producers. In both veal and beef production,the effects of dam breed were less important than sirebreed. Considering the entire project, we can concludethat the combined use of sexed semen for purebreedingand conventional beef semen for terminal crossbreedingimproves meat production from dairy herds, especiallywhen the sires are double-muscled beef breeds.