One hundred and eight high genetic merit Holstein-Friesian heifers were used to determine the effects of rearing regime on the development of the mammary gland and claw abnormalities. Heifers were allocated to one of four rearing regimes at 7 weeks of age and slaughtered at 18 (s.d.0.7) months of age; mating commenced at 14 months of age. Treatment 1 heifers were reared to calve at 540 kg and treatments 2, 3 and 4 heifers reared to calve at 620 kg. Treatment 1 and 2 heifers were offered grass silage-based diets during the winter and grass-based diets during the summer; treatment 2 heifers received additional concentrates. Treatment 3 heifers were offered a straw/concentrate diet during the winter and a grass-based diet during the summer. Treatment 4 heifers received the same winter diets as treatment 3 but were housed and offered a straw/concentrate diet in summer. Increasing plane of nutrition increased the weight of dissected udder fat (P < 0.01), but had no effect on the weight or chemical composition of dissected udder parenchyma. Offering straw- compared with silage-based diets reduced fat deposition in the udder (P < 0.01) and increased the proportion of parenchyma in the udder (P < 0.01). Keeping heifers housed during the first summer and offering straw-based diets relative to those turned out to grass had no effect on weight of fat although there was a tendency towards a reduction in the proportion of parenchyma in the udder (P < 0.06). Heifers reared on a low plane of nutrition had lower values for heel height (P < 0.001), lateral claw length (P < 0.001) and heel erosion scores (P < 0.01). A higher plane of nutrition also increased live weight/sole area although this was only significantly higher for treatment 3 (P < 0.05) compared with treatment 1 heifers. Housing heifers in the first summer increased the incidence of feet lesions in the white line area and solear area relative to turning heifers out to grass in the first summer (P < 0.05).

The claw geometry of birds can be used to predict their mode of life. Previous studies, however, have not considered how bird size might affect these predictions. Thus, in the present study, the geometric scaling relationships of bird claws are examined for a variety of extant birds with different modes of life: predatory, climbing, perching or ground-dwelling. Measurements of hind-limb claw radius (i.e. claw size) and claw angle (i.e. claw ‘hookedness’) of the third digit claw were made on 120 species of bird ranging from 0.0057 kg to 44 kg in body mass. Claw radius was found to be proportional to (body mass)0.34 across all species. Claw angle was found to increase with body mass for predatory and climbing birds (i.e. bigger birds have relatively more hooked claws), and decrease with body mass for ground-dwelling birds (i.e. bigger birds have relatively less hooked or flatter claws). No significant relationship was found between claw angle and body mass for perching birds. Mode of life could not be predicted with any certainty using measurements of either claw radius or claw angle, suggesting difficulty in assigning fossil species such as Archaeopteryx to a specific locomotor category. As claw design should enable the claw to withstand the forces placed upon it, further work is needed to establish the stresses experienced by the claws of different types of bird.

The effects of floor type and stocking density on leg weakness, osteochondrosis and claw disorders in slaughter pigs were studied. Three hundred pigs were housed in pens with either solid floors with plenty of straw, solid floors without straw or fully slatted floors at either high (0·65 m2 per pig) or low (1·2 m2 per pig) stocking density from 25 to 105 kg. In each pen half of the pigs were boars and half gilts of the breeds Landrace and Yorkshire ✕ Landrace crossbred. There was no difference in growth rate between the three floor types. The growth rate of the boars was higher at low compared with high stocking density, while no effect of stocking density was seen in the gilts. The prevalence of leg weakness and claw disorders was different for the various floor types, while no effect of floor type could be found on joint changes. With regard to leg weakness, slatted flooring was significantly worse than solid floors with or without straw for standing under position on hind legs, while pens with plenty of straw were significantly better than the other floor types with regard to stiff movement and forelegs turned out. A calculated sum of the nine leg weakness symptoms showed that pens with straw were the best followed by solid floor without straw, while slatted floors were the worst. Regarding claw disorders, solid floors without straw were the worst. High stocking density affected four leg weakness variables (buck-kneed forelegs, turned-out fore- and hind legs, standing under position on hind legs), one joint change and three claw disorders negatively. Boars scored worse than gilts with regard to one leg weakness trait and one claw disorder and thickening of cartilage in two joints. Differences between breeds differed for the examined variables. Claw hardness was affected by floor type with regard to medial claws, which were softer on slatted floors. The hind claws were softer than the foreclaws on the volar surface, while there was no difference between the hardness of the topside of the fore- and hind claws. Claw hardness was not affected by sex. In conclusion, it can be said that the examined floor types do not have the same effect on the different aspects of leg weaknesses and claw disorders. Thus, clinical leg problems are worst on slatted floors and best in pens with straw, but claw disorders are worst on solid floors without straw. Further, high stocking density specifically affects the clinical leg weaknesses and claw disorders. Joint changes were not affected by floor type or stocking density.

The cheetah Acinonyx jubatus is the most cursorial felid and has been described as somewhat dog-like in both the shape and the diminished degree of retraction of the claws. In this study we evaluate and investigate the osteological correlates associated with claw retraction in the cheetah through a comparison of the morphology of its middle phalanges with those of other felids and of the wolf Canis lupus. Compared to other felids, the middle phalanges of the cheetah have better-developed grooving of the distal articulatory facets in both the manus and pes, reduced to absent angulation to the distal articulatory facets in the inner and outer digits, less marked asymmetry of the shaft, and a mid-shaft cross-section that is less triangular and more circular. In all of these features, the morphology of the cheetah is intermediate between that of other felids and that of the wolf. The cheetah's distinctive morphology is autapomorphic within Felidae and similarities between the cheetah and the wolf are the result of convergence. Study of an ontogenetic series of specimens of the domestic cat suggests that the morphology of the cheetah can be explained, at least in part, as a product of heterochrony in which the development of the middle phalanx is truncated at an earlier stage than is typical of the adults of other felids. Some of the morphological differences in the middle phalanges of the cheetah can be associated with its distinctive hunting behaviour. The reduced manipulative capabilities of the forelimb associated with the evolution of cursorial adaptations seem to have limited the roles of the forepaws in both the subduing of prey and feeding.