An assessment of the production, reproduction, and functional traits of Holstein-Friesian, Jersey × Holstein-Friesian, and Norwegian Red × (Jersey × Holstein-Friesian) cows in pasture based systems

摘要

Pasture-based production systems typically requirehighly fertile, healthy, and robust genetics, with greateremphasis on milk solids (Mso; kg of fat + protein) productionas opposed to milk yield. This study assessedmilk production, production efficiency, reproductiveperformance, body weight (BW), body condition score,and functional traits in 3 different dairy cow genotypes:Holstein-Friesian (HF), Jersey × Holstein-Friesian(JEX), and Norwegian Red × (Jersey × Holstein-Friesian) (3-way). The 3 genotypes were rotationallygrazed on 4 different grazing treatments after calvingin spring and were stocked at a rate of 2.75 cows/ha.Holstein-Friesian cows produced higher daily and totalmilk yields compared with JEX and 3-way cows (5,718vs. 5,476 and 5,365 kg/cow, respectively). However,JEX and 3-way cows had higher milk fat and proteincontents (4.86 and 4.75%, respectively, for JEX and3.87 and 3.88%, respectively, for 3-way) compared withHF (4.52 and 3.72%), resulting in similar Mso yieldfor JEX and HF (469 and 460 kg/cow) and slightlylower Mso yield for 3-way (453 kg/cow) comparedwith JEX. As parity increased, milk and Mso yield percow increased. Reproductive performance was not significantlydifferent between the 3 genotypes, which hadsimilar 24-d submission rates, 6-wk pregnancy rates,and overall pregnancy rates over the 4-yr period. Nodifference in calving difficulty, incidence of mastitis, orincidence of lameness was observed among the 3 genotypes.Body weight was significantly different amongall 3 genotypes, with HF being the heaviest followed by3-way and JEX (530, 499, and 478 kg, respectively), and3-way cows had a higher body condition score throughoutlactation compared with HF and JEX cows. Thedifferences in BW coupled with similar Mso productionresulted in JEX cows having the highest productionefficiency (4.58 kg of Mso/kg of metabolic BW), 3-waycows being intermediate (4.30 kg of Mso/kg of metabolicBW), and HF cows having the lowest (4.16 kg ofMso/kg of metabolic BW). In conclusion, HF herdswith poor reproductive performance and low milk fatand protein contents are likely to benefit considerablyfrom crossbreeding with Jersey, and all herds are likelyto benefit in terms of production efficiency. However,where herd performance, particularly in relation to reproductiveperformance, is comparable with HF in thecurrent study, crossbreeding with Jersey or NorwegianRed is unlikely to lead to significant improvements inoverall herd performance.