Area of hock hair loss in dairy cows: risk factors and correlation with a categorical scale.

Data from 3691 dairy cows from 76 farms were used to investigate the risk factors associated with the area of hair loss over the lateral aspect of the hock and the correlation between the area of hair loss (as calculated using a hock map) and hock lesion scores determined using a pre-existing categorical scale. Six factors were associated with a greater area of hair loss, including cows with locomotion score 3, a cleanliness score (10/28 to 18/28), high daily milk yield (25.1-58.1 kg), poor body condition score (1-1.5), duration of winter housing (≥41 days) and some combinations of cubicle base and bedding materials. Compared with cows housed in cubicles with a concrete base and whole straw or rape straw bedding, cows housed in cubicles with concrete bases with sand or chopped straw bedding had smaller areas of hair loss and cows housed on a mattress base with whole straw or rape straw bedding had larger areas of hair loss. Area of hair loss, as measured on hock maps, was not significantly different between cows with score 1 (median 23.6 cm(2)) and score 2 (median 20.3 cm(2)) on the categorical scale for hock lesions. This suggests that the categorical scale was not reflecting the extent of hair loss and that hock maps are a good alternative for studying the dynamics of hock lesions over time.

Variation in enteric methane emissions among cows on commercial dairy farms.

Methane (CH4) emissions by dairy cows vary with feed intake and diet composition. Even when fed on the same diet at the same intake, however, variation between cows in CH4 emissions can be substantial. The extent of variation in CH4 emissions among dairy cows on commercial farms is unknown, but developments in methodology now permit quantification of CH4 emissions by individual cows under commercial conditions. The aim of this research was to assess variation among cows in emissions of eructed CH4 during milking on commercial dairy farms. Enteric CH4 emissions from 1964 individual cows across 21 farms were measured for at least 7 days/cow using CH4 analysers at robotic milking stations. Cows were predominantly of Holstein Friesian breed and remained on the same feeding systems during sampling. Effects of explanatory variables on average CH4 emissions per individual cow were assessed by fitting a linear mixed model. Significant effects were found for week of lactation, daily milk yield and farm. The effect of milk yield on CH4 emissions varied among farms. Considerable variation in CH4 emissions was observed among cows after adjusting for fixed and random effects, with the CV ranging from 22% to 67% within farms. This study confirms that enteric CH4 emissions vary among cows on commercial farms, suggesting that there is considerable scope for selecting individual cows and management systems with reduced emissions.

A descriptive review of the peer and non-peer reviewed literature on the treatment and prevention of foot lameness in cattle published between 2000 and 2011.

The aim of this study was to collate and review the peer and non-peer reviewed English language literature on the treatment and prevention of foot lameness in cattle published since January 2000. The study aimed to identify deficits in knowledge and areas of disparity between what is recommended in the field by veterinarians, foot trimmers and advisors and what has been substantiated experimentally. Peer reviewed literature containing original work was gathered by searching three databases. Papers were categorised and reviewed if they contained material on treatment or prevention. Non-peer reviewed clinical materials were collated from a range of sources. The materials were reviewed and categorised based on whether they recommended a range of possible treatment and prevention strategies. The peer reviewed data base contained 591 papers, of which 286 contained information on treatment or prevention. The vast majority of papers (258) concerned prevention; only a small number covered treatment (31) and of these only three contained information on the treatment of sole ulcers or white line disease. The number of intervention studies and trials was low; most papers on prevention were observational. Generally, lesion specific outcomes were not described making the findings of these papers difficult to use clinically. The non-peer reviewed material contained 46 sources; they varied significantly in regard to the treatments they advocated with some texts directly contradicting each other. Some aspects of prevention recommended in these sources seemed poorly supported by findings from the research literature. Well designed intervention studies are required to address these deficits.

Prevalence and characterisation of, and producers' attitudes towards, hock lesions in UK dairy cattle.

The objectives of this paper were to characterise lesions found at the hock and to establish their prevalence across a large sample of dairy cows in the UK. In addition, the study aimed to examine farmers' perceptions of these lesions. Seventy-seven farms were visited; both hocks on a random sample of approximately 50 cows were scored on a categorical scale for hair loss, ulceration and swelling. In addition, the size and location of lesions were marked on a hock map. A questionnaire designed to explore attitudes towards lesions was conducted with the owner. Hair loss and ulceration were seen at five locations. Hair loss was identified on 5,619 of 6,896 hocks (mild: 43.7 per cent; moderate: 25.1 per cent; severe: 12.6 per cent) and 1,137 of 6,896 hocks had areas of ulceration (mild: 8.6 per cent; moderate: 5.8 per cent; severe: 2.1 per cent). The majority of lesions were small; however, a small proportion had extensive areas of hair loss (maximum size 113.3 cm2) and ulceration (maximum size 95.5 cm2). Moderate swelling was recorded on 20 per cent of hocks, and 2.0 per cent had severe swelling. Interview results suggested that more than 90 per cent of participants were aware of hock lesions and a third had sought treatment for them; most felt that lesions had at least some impact on productivity and welfare.

Risk factors associated with hair loss, ulceration, and swelling at the hock in freestall-housed UK dairy herds.

The objective of this study was to identify the risk factors associated with 3 presentations of hock lesions (hair loss, ulceration, and swelling) in freestall-housed lactating cattle. By independent identification and scoring of, and analysis of the factors associated with, hair loss, ulceration, and swelling, the aim was to identify whether risk factors were common to all 3, or differed among the presentations. A cross-sectional study was conducted on 76 herds in the UK during the winter housing period of 2007 to 2008, with a total of 3,691 cows examined for hock lesions. A randomly selected sample of approximately 50 cows in each herd were scored for body condition, lameness, cleanliness, rising behavior, and lesions at the hocks. For all cows, hair loss, ulceration, and swelling were scored separately on 4-point scales, with both left and right hocks scored. Based on a review of the literature, potential risk factors were identified and measured, collected from milk-recording data, or obtained through interviews with the farmers. Risk factors associated with hocks lesions in cattle were examined using data from the 2,982 cows housed in the 63 freestall-housed herds visited. Risk factors for each of the 3 lesion presentations were considered separately in multilevel logistic regression models, with moderate or severe hair loss, any degree of ulceration, and moderate or severe swelling as the outcome variables. Thirty risk factors were identified, none of which were common to all 3 lesion presentations. Five risk factors (locomotion score, number of days of winter housing, mean milk yield, freestall base material, and herd size) were common to both hair loss and ulceration. The stall bedding material was a common risk factor for both hair loss and swelling. A further 8, 5, and 11 risk factors were unique to hair loss, ulceration, and swelling, respectively. The existence of several differential risk factors between the 2 lesion presentations suggests that ulceration may not always be a direct extension of hair loss, as has been implied in previous scoring systems. Of the 12 risk factors associated with swelling, only 1 was common to another lesion presentation, which suggests that swelling may have a different etiology than hair loss and ulceration. The variables associated with the lesions indicate the importance of factors that affect the lying and rising behavior of the animal, including freestall structure and design, and the lying surface.