The development, implementation and testing of a lameness control programme based on HACCP principles and designed for heifers on dairy farms.

This paper describes the development and testing of a lameness control programme (LCP) for heifers on dairy farms. The LCP, which is based on the analysis of hazards and critical control points (HACCP), was tested via a randomised intervention study on 60 farms. Tangible hazards for each farm were identified, allotted to 11 categories of proximate hazard and scored on each farm to quantify the risks presented by each hazard. Feet were inspected for signs of claw horn disease and infection, such as digital dermatitis. Intervention was generally ineffective, primarily through failure to implement the LCP. However, retrospective analysis was able to demonstrate highly significant associations between risks attached to proximate hazards and probabilities of lameness and foot lesions, allowing the severity of these hazards to be ranked. The most significant proximate hazards of environmental origin were prolonged standing on concrete, standing in wet slurry and factors that cause claw trauma. The most severe proximate hazards however were those associated with failures of management, especially poor claw condition and inadequate foot care. Overall farm risks (OFR) were estimated by summing the products of the generic severity for proximate hazards with on-farm risks. Changes in OFR were significantly related to changes in outcome (lameness and lesions).

Assessment of the behaviour and welfare of laying hens on free-range units.

The aims of this study were twofold: to develop and test an animal-based protocol for the assessment of the physical and emotional elements of the welfare of laying hens on free-range units and to investigate the effects of different approaches to housing and management on the welfare of the birds. The protocol was tested on 25 free-range units for laying hens, each of which was visited on four occasions by one of five trained observers; further information about husbandry, health and productivity was gathered from interviews with the farmers. Measures of the birds' attitude included arousal, noise, flight distance and response to a novel object, measures of their activity included feather pecking, aggression and use of range, and measures of their physical welfare included mortality, body condition and egg quality. Increased arousal was associated with increased flight distance, greater reluctance to approach a novel object and higher levels of feather pecking and feather loss, but the correlation between pecking and feather loss was low. The birds maintained body condition throughout the period of lay. Neither body condition, feather pecking nor feather loss was affected by the extent of beak trimming. Estimated losses (deaths and culls) ranged from 1.8 to 21.4 per cent (median 6.95 per cent). Few birds showed signs of ill health, limb lesions or red mite infestation. No feature of building design had a significant effect on mortality, but there were consistent differences in the birds' attitude, behaviour and performance attributable to the type of floor and the presence or absence of perches, which suggested that the welfare of the hens was inferior when they were housed on plastic floors with no perches.

Effects of housing, parturition and diet change on the biochemistry and biomechanics of the support structures of the hoof of dairy heifers.

This study investigated effects of housing, diet and parturition on the biochemistry, biomechanics and pathology of feet of maiden, pregnant and lactating dairy heifers. Strength/laxity, laminar morphology, connective tissue (CT) biochemistry and sole lesions were assessed. Although no animals became clinically lame, severity of sole lesions was significantly greater in heifers housed in cubicles vs. straw yards, and in lactating/pregnant heifers vs. maidens. These effects were additive. Cubicle housing and parturition each increased CT metabolism (and were additive), and altered CT composition. Similarly, both impaired the biomechanical resilience of the hoof. There were no effects for diet. The results indicate that parturition/lactation causes non-inflammatory changes in CT that impair resilience of the feet to external stresses associated with poor housing. This "parturition effect" appears to be unrelated to change in diet and relatively brief, unless exacerbated by additional stresses of housing. Thus heifer lameness may be significantly reduced through short-term, low-cost improvements in husbandry around the time of calving.

Herd health planning: farmers' perceptions in relation to lameness and mastitis.

Between December 2002 and December 2003, the herd health planning activities on 61 dairy farms in the uk were compared with several measures of lameness and mastitis. Lameness had been reported as a problem in 53 of the herds directly by the farm and in the other eight by the nominating local veterinary practice; 54 of the farms also reported having a mastitis problem. Fifty-three (87 per cent) of the farms had some form of written herd health plan, of which 21 (40 per cent) had been in place for 12 months or less. All the farms were recording mastitis in some way, although 38 (62 per cent) of the farmers did not review these records and only four retained the results of a comprehensive record review. Farms defined as having a high incidence of mastitis were more likely to be reviewing their health records, but farms defined as having a high prevalence of lameness in a sentinel group of early lactation heifers were less likely to be reviewing their health records.

Role of ketoprofen in the modulation of hyperalgesia associated with lameness in dairy cattle.

Forty lame dairy cows were randomly assigned to receive a course of either the non-steroidal anti-inflammatory drug ketoprofen, or sterile saline, together with conventional treatment for lameness. The effect of the ketoprofen was measured by using locomotion scoring and by testing the cows' nociceptive threshold over a period of 28 days. The locomotion score of all the cows improved but ketoprofen had no significant effect on this change. However, in the cows that received ketoprofen the hyperalgesia associated with lameness, recorded using a nociceptive threshold test, was significantly modulated on days 3, 8 and 28 after their initial examination, drug administration and treatment of lesions.

Assessment of the welfare of dairy cattle using animal-based measurements: direct observations and investigation of farm records.

A protocol was developed by consultation with experts on the welfare of cattle to use direct observations of cattle and an examination of farm records to assess welfare. Fifty-three dairy farms in England were visited and assessed during the winter of 2000/01. The findings were compiled and the results of the welfare measurements were examined by 50 experts who indicated at what level they considered that improvement was required. More than 75 per cent of them considered that 32 of the 53 farms needed to take action to reduce the incidence of mastitis, and that at least 42 of the farms needed to take action to reduce the prevalence of lameness, overgrown claws, swollen and ulcerated hocks, and injuries from the environment.

Effect of the RSPCA Freedom Food Scheme on the welfare of dairy cattle.

To evaluate the effect of the Royal Society for the Prevention of Cruelty to Animals Freedom Food (FF) scheme on the welfare of dairy cattle in England, 28 FF and 25 non-FF farms were assessed during the winter of 2000 to 2001. The assessments were based on a protocol which included the examination of the farms' records, the farmers' estimates of the incidence of disease, and independent observations of the behaviour and physical condition of the cows. The data were analysed to identify which measures of welfare were affected by FF membership and to assess the number of farms on which intervention would be required, as defined by a panel of 50 experts. The FF farms had better results for 12 of the welfare indicators, including those for mastitis, non-hock injuries, cow cleanliness and body condition, and poorer welfare indicators for eight of the measures, including hock injuries, lameness and restrictions in rising behaviour. Except for the prevalence of dull coats (which was lower on the FF farms) there were no significant differences in the proportions of FF and non-FF farms on which intervention was required according to the experts' assessment.

Effects of housing practices on the development of foot lesions in dairy heifers in early lactation.

Measurements were made of sole haemorrhages and white line lesions in two groups of heifers which were either introduced to a cubicle house four weeks before they calved (group 1) or housed in a straw yard for eight weeks after calving and then moved into the cubicle house (group 2). The overall severity of the lesions was described by a cumulative score which defined the product of the severity and the area of the overall lesions in each animal. The lesions were scored on six occasions, from four weeks before to 24 weeks after parturition. Before parturition, sole lesions were absent or very small. By four weeks after calving, most of the animals had both types of lesion, but the differences between the two groups were small and statistically insignificant. There were no significant differences in the white line lesions between the two groups at any of the observations. There were, however, progressive, highly significant differences between the two groups in the severity of sole haemorrhages. By 12 weeks after calving, the median score for group 1 was 69 and that for group 2 was 11. In group 2, the sole haemorrhage score peaked at eight weeks but declined thereafter, even though these animals were moved into cubicles eight weeks after calving. By 12 weeks after calving, six of the 17 heifers in group 1 had sole ulcers but none of the 16 in group 2 had ulcers.

Biomechanical and histopathological changes in the support structures of bovine hooves around the time of first calving.

Hooves were removed from heifers killed two weeks before calving (C-2), and four and twelve weeks post-calving (C+4 and C+12), and from age-matched maiden heifers. Segments were dissected from the anterior walls of lateral hind claws, to include horn, corium and bone, and the biomechanical properties were measured. There was reduced rigidity, both overall and at a physiologically appropriate displacement of 2 mm, and a greater displacement was required to reach initial and maximum support in the hooves of calving, compared with maiden, heifers. Histological examination revealed widened and distorted interdigitating laminae, progressing to C+12 in the hind claws, but with evidence of recovery in the front claws after C+4. Increased connective tissue strength from dorsal to ventral hoof segments was correlated with protein, proteoglycan, pro- and activated matrix metalloproteinase-2, and tissue inhibitors of metalloproteinases, and was inversely correlated with fat, water and collagen content. This implies that mechanical changes reflect alterations in the biochemistry of the connective tissue. This evidence supports the hypothesis that primary causal events associated with calving weaken the connective tissue of the hoof suspensory apparatus, leading to increased susceptibility to clinical lameness associated with sole ulcers and white line disease.