Transition cow health and management in pasture-based dairy herds: A farmers' survey

Seasonal-calving pasture-based systems characterize Irish dairy production. During the dry period, cows are housed and offered predominantly grass silage, providing unique transition cow management opportunities. This study aimed to describe transition period disease incidence and management strategies reported by farmers, and to evaluate their associations with herd size and calving pattern to inform and guide research activities and national advisory. An online survey distributed amongst 3,899 Teagasc Technical Dairy Advisory clients yielded 525 responses suitable for analysis. Results are presented for all respondents, by herd size and by the two most common calving systems (spring- [84.3%; 439/521] and split-calving [12.9%; 67/521]). Disease incidence was reportedly highest in cows within their first 3 weeks postpartum (58%; 299/519), in cows calving at the end of the calving season (48%; 245/510) and in multiparous cows (52%; 266/513). Respondents reported treating >3% of their herd for milk fever (23%; 120/521) and retained placenta (13%; 68/518), and <1% of their herd for grass tetany (82.6%; 419/507) and ketosis (72.7%; 368/506). Regarding management, dry cow body condition monitoring (73%; 365/497), dry cow mineral supplementation (61%; 304/497), and Ca supplementation at calving (61%; 314/487) were most commonly reported. Other milk fever prevention strategies supported by research in other production systems were not commonly reported (low K [20%; 101/497] and negative dietary cation-anion difference diet [6%; 31/497]). The odds of reporting keeping records of antibiotic treatment for milk fever were higher (OR = 3.20) for farmers from small compared to large herds. In conclusion, responses to our survey suggest that milk fever is a transition cow health concern in Irish dairy farms. Efforts should be devoted to enhance farmers' uptake of existing research-supported prophylactic strategies for milk fever and to optimize commonly reported management strategies in the Irish dairy production context.