The effect of Lameness before and during the breeding season on fertility in 10 pasture-based Irish dairy herds.

BACKGROUND: The effects of lameness on fertility have been documented frequently but few data are available from seasonally breeding, pasture-based herds (such as those used in Ireland) where cows are housed during the winter months but managed at pasture for the remainder of the year. This study determined the prevalence of lameness in a group of 786 cows in 10 pasture-based Irish dairy herds before, during and after the breeding season and assessed the relationship between lameness and the reproductive performance in these herds through serial locomotion scoring during the grazing period. RESULTS: Lameness prevalences of 11.6 % before, 14.6 % during and 11.6 % after the breeding season were found and these compared favourably to results from housed cattle and are similar to other studies carried out in grazing herds. A Cox proportional hazards model with locomotion score as time varying covariate was used. After controlling for the effect of farm, month of calving, body condition score at calving, body condition score loss after calving and economic breeding index, cows identified as lame during the study were less likely to become pregnant. Cows lame before the earliest serve date but no longer lame during the breeding season, cows becoming lame after the earliest serve date and cows identified lame both before and after this date were respectively 12 %, 35 % and 38 % less likely to become pregnant compared to cows never observed lame during the study. However, these findings were only significant for cows becoming lame after the earliest serve date and cows lame both before and after the start of breeding. CONCLUSIONS: This study found that the reproductive efficiency was significantly (p < 0.05) lower in cows becoming lame during the breeding season and cows lame before and during the breeding season compared to non-lame cows. Cows no longer lame during the breeding season had a lower Submission Rate to first serve within 3 weeks of earliest serve date. However, the Pregnancy Rate was not significantly (p > 0.05) lower in these animals compared to cows never diagnosed as lame. In addition to lameness status, nutritional status and genetics were found to influence the reproductive performance in pasture-based Irish dairy herds.

Routine Herd Health Data as Cow-Based Risk Factors Associated with Lameness in Pasture-Based, Spring Calving Irish Dairy Cows.

Herd-level risk factors related to the cow's environment have been associated with lameness. Uncomfortable stall surface and inadequate depth of bedding as well as abrasive alley way surface are contributing factors to increased levels of lameness. Access to pasture has been found as having a beneficial effect on cows' locomotion. However, dairy cattle managed under grazing conditions are exposed to a different set of risk factors for lameness, mainly associated with cow tracks. Cow-based risk factors for lameness are not as clearly defined as the herd level risk factors. The objective of the present study was to use routine herd health monitoring data to identify cow-based risk factors for lameness and utilise this information to indicate cows at risk of developing lameness in the first 150 days of lactation. Lameness data were gathered from 10 pasture-based dairy herds. A total of 1715 cows were monitored, of which 1675 cows were available for analysis. Associations between lameness status and potential cow-level risk factors were determined using multivariable logistic regression. Parity 3 and 4 + cows showed odd ratios (OR's) for lameness of 3.92 and 8.60 respectively (95% confidence interval (CI) 2.46-6.24; 5.68-13.0). Maximum loss of Body condition score (BCS) after calving exhibits OR's for lameness of 1.49 (95% CI 1.08-2.04) if cows lost 0.5 in BCS after calving and 2.26 (95% CI 1.30-3.95) for cows losing more than 0.5 BCS. Animals calving in BCS 3.25 and ≥ 3.5 had correlating OR's of 0.54 (95% CI 0.34-0.87) and 0.33 (95% CI 0.16-0.65) for being lame compared to cows calving with BCS ≤ 2.75. Data gathered as part of herd health monitoring can be used in conjunction with lameness records to identify shortcomings in lameness management. Findings and recommendations on lameness management can be formulated from readily available information on cow-based risk factors for lameness.

Association of lameness and mastitis with return-to-service oestrus detection in the dairy cow.

Oestrus detection is an important part of maintaining efficient reproductive performance in dairy herds. Both lameness and mastitis are common diseases of dairy cows that may impact oestrus detection. A set of data from 28 herds identified as having good recording of clinical mastitis and lameness incidents was used for the study. Logistic regression was used to identify associations between disease episodes within 100 days of insemination and changes in the probability of reinsemination at either 18-24 or 19-26 days after an unsuccessful insemination. Population attributable risk was calculated to understand the impact these diseases may have at a herd level. Lameness 0-28 days after the first insemination of the interval decreased the odds of a reinsemination at an appropriate time by approximately 20 per cent. Clinical mastitis 1-28 days prior to the first insemination of the interval increased the odds of reinsemination at the expected time by approximately 20 per cent. The associations were similar for either interservice interval outcome. Population attributable risk suggested that the effect of these diseases on the probability of reinsemination at the expected time at a population level would likely be extremely small.

Making Good Decisions on Dry Cow Management to Improve Udder Health - Synthesising Evidence in a Bayesian Framework.

The dry period is now recognised as a critical time for the control of clinical and sub-clinical mastitis in dairy cattle. Infections that occur, or that are not cured, during the dry period often result in clinical mastitis or raised somatic cell counts in early lactation. There is known to be large variability between herds in the patterns of dry period intramammary infections (IMI) and yet, until recently, there has been no information on farm determinants of the risk of IMI, other than in relation to dry cow treatments. In this paper we consider new research on cow characteristics, farm facilities and herd management strategies during the dry period in relation to clinical mastitis and raised somatic cell counts (SCC) in early lactation. We then describe, within a Bayesian framework, the concept of synthesising existing knowledge with new data to facilitate decision-making on dry cow management for individual farms.

Clinician attitudes to pain and use of analgesia in cattle: where are we 10 years on?

Pain in cattle can arise though disease or injury or may result from veterinary or husbandry procedures. Controlling pain is important to safeguard animal welfare. Previous studies indicated that the use of analgesics in cattle has lagged behind use in companion animals. Over the last decade, more analgesic products have become available for use in cattle and there have been increased efforts to communicate the importance and benefits of analgesia. A questionnaire (based on that used in a similar study published in 2006) was sent to UK cattle practitioners asking them to score pain severity for several conditions of cattle and asking about their attitudes towards and use of analgesic medicines. A total of 242 surveys were returned. Male clinicians and those graduating before 1990 scored pain severity significantly lower and were significantly less likely to use NSAIDs. Generally, use of NSAIDs was more common for conditions assigned higher pain scores. However, uptake of NSAID use was much lower for a number of routine procedures in calves than would be expected from the pain scores they were assigned. A need remains to increase use of analgesic products, especially NSAIDs in calves, in line with best practice recommendations.

Cattle practice: ready to adapt to a changing world?

How well placed is UK cattle practice to meet future challenges? This question was addressed at a recent meeting of the Nottingham Dairy Health Innovation Forum. Forum member, Jon Huxley, reports on the outcome.