Temporal trends in reproductive performance in Irish dairy herds and associated risk factors

Abstract

Irish dairy herd fertility has been declining since the 1980s. The extent, nature and causes of this decline in fertility and the current status of Irish dairy herd fertility were described. An increase in calving interval of approximately one day per year has been recorded. The principal components of this trend have been an increased incidence of postpartum endocrinopathies, reduced expression of oestrus and a fall in conception rate. Both submission rate and calving-to-service interval have increased slightly over time. Significant risk factors associated with these trends have been strain substitution within the Holstein-Friesian breed and single trait selection for milk production. Critically, these changes have been reflected in loss of body condition. Contributory factors included increased herd size and possibly increased use of DIYAI. The most recent Irish study showed that 48% of cows conceived to first service and 14% of cows were not pregnant at the end of the industry-average 15-week spring breeding season. However, the top quartile of herds achieved a first-service conception rate of 59%, illustrating the wide variation between herds. These phenotypic trends were attributed to both genetic and environmental factors and their interactions. Recent Irish dairy herd fertility performance falls short of the targets set for seasonal compact calving.

Farmers' attitudes towards techniques for improving oestrus detection in dairy herds in South West England

“…Laven (2004) suggests that oestrus is more difficult to detect than 25 years ago because heats have become both shorter and weaker. Similar conclusions emerge from recent Irish research (Mee, 2004;White and Sheldon, 2001).…”

Pre‐breeding Ovaro–Uterine Ultrasonography and its Relationship with First Service Pregnancy Rate in Seasonal‐Calving Dairy Herds

“…2000). A more recent Irish study of six dairy herds using milk progesterone measurement found that 15% of cows had not commenced luteal activity by 45 days postpartum (Mee 2004). Yet, the prevalence and interherd variation of anovulatory anoestrus in these Irish herds was lower than that in 26 seasonal‐calving pasture‐based herds in New Zealand (27%, herd range 13–48%), (Rhodes and Morgan 1999) or in Belgium (22% anovulatory anoestrus at 50 days postpartum in six herds), (Opsomer et al.…”

“…Although palpation per rectum is most widely used for determination of ovarian structures in veterinary cattle practice, this modality is less accurate than ultrasonography in detecting, measuring and enumerating follicular and luteal structures (Hanzen et al 2000). A more recent Irish study of six dairy herds using milk progesterone measurement found that 15% of cows had not commenced luteal activity by 45 days postpartum (Mee 2004). Yet, the prevalence and interherd variation of anovulatory anoestrus in these Irish herds was lower than that in 26 seasonal-calving pasture-based herds in New Zealand (27%, herd range 13-48%), (Rhodes and Morgan 1999) or in Belgium (22% anovulatory anoestrus at 50 days postpartum in six herds), (Opsomer et al 2000), or in North America (38% anoestrus at ‡60 days postpartum) (Lucy 2001).…”

Effect of milking frequency in early lactation on energy metabolism, milk production and reproductive performance of dairy cows

“…Irish data show that there was a significant decline in calving rate to first service between 1991 and 1998 of approximately 0.9% per annum (Mee, 2004). A recent survey of 74 farms, incorporating records from over 6000 cows, showed that conception rate to first service was 49% (26-87% by herd), (Buckley et al, 2003).…”