A comparison of different dairy cow breeds on a seasonal grass-based system of milk production: 2. Reproduction and survival
2003
Dillon, P. | Snijders, S. | Buckley, F. | Harris, B. | O'Connor, P. | Mee, J.F.
Reproduction and survival characteristics of Dutch Holstein-Friesian (HF), upgraded Irish Holstein-Friesian (CL), French Montbeliarde (MB) and French Normande (NR) cows were compared over a 5-year period (137 lactations per breed), in a seasonal grass-based milk production system. The HF had the highest (P<0.05) milk yield at first AI, and the NR had the lowest milk yield; the values for the other two breeds were intermediate. The MB and NR had higher (P<0.05) live weight and body condition scores at first AI than the HF and CL. Similarly, the MB and NR had higher (P<0.05) nadir live weights and nadir condition scores. The HF had greater (P<0.05) reduction in body condition score from calving to first AI than the other three breeds. At the end of the 14 weeks of breeding, significantly (P<0.05) more of the HF cows (26.3%) were not pregnant than the CL cows (16.1%); both of these non-pregnancy levels were higher than the corresponding MB (8.8%) and NR (8.1%) levels. Similarly, the pregnancy rate to first AI of the HF was lower (P<0.05) than the MB and NR. Furthermore, the HF cows had extra number of days from calving to conception than the other three breeds (P<0.05). Dairy cow breed had a significant effect on survival; 20.6, 39.7, 49.2 and 55.8% to day 2500 for the HF, CL, MB and NR, respectively. The results of the present study indicate that the reproductive performance and survival of HF with a large proportion of North American genes are low in a seasonal grass-based milk production system.
显示更多 [+] 显示较少 [-]