To explore how hoof pathologies affect the gait of dairy cattle, we studied gait profiles of cows with no visible injuries (n = 17), sole lesions (n = 14), and sole ulcers (n = 7). Video recordings of dairy cows were digitized using motion analysis software to calculate 6 stride variables for each hoof. Compared with cows with sole ulcers, healthy cows walked faster (1.11 +/- 0.03 vs. 0.90 +/- 0.05 m/s, mean +/- SEM), had shorter stride durations (1.26 +/- 0.03 vs. 1.48 +/- 0.05 s), and longer strides (139.5 +/- 2.1 vs. 130.0 +/- 3.2 cm). Percentage of triple support in the gait cycle (time when cattle were supported by 3 legs) more than doubled for cows with sole ulcers compared with healthy cows (42 vs. 18%). Gait differences were likely due to cows reducing the load on an affected leg. Few differences were detected between healthy cows and those with sole lesions, perhaps because of variation in number, severity, and location of injuries. Kinematic gait analysis is a promising approach in understanding how hoof pathologies affect dairy cow gait.

We studied cows with (n = 6) and without (n = 26) sole ulcers before and after milking to explore how milking influences dairy cattle gait and how this differs for cows with hoof injuries. Video recordings of cows were digitized using motion-analysis software to calculate stride variables for each hoof. Gait was scored using a 1-to-5 numerical rating system (1 = sound, 5 = severely lame) and a continuous 100-unit visual analog scale of gait attributes (back arch, head bob, tracking-up, and reluctance to bear weight). For cows with and without sole ulcers, differences in gait before and after milking were evident; after milking, all cows had significantly longer strides (123.3 vs. 133.5 +/- 2.0 cm, respectively), higher stride height (8.3 vs. 8.9 +/- 0.1 cm), shorter stride durations (1.49 vs. 1.41 +/- 0.03 s), walked faster (0.85 vs. 0.97 +/- 0.03 m/s), and had shorter periods of triple support (3 legs in ground contact; 80.0 vs. 71.7 +/- 2.0%). Tracking-up and reluctance to bear weight improved after milking (20 vs. 16 +/- 2; 20 vs. 15 +/- 1, respectively), but numerical rating scores and back arch did not. Cows with sole ulcers walked differently than cows without for all measures, except swing duration, both before and after milking. Interactions between hoof health and milking were found for swing duration and head bob but when tested separately, the only effect was that cows without sole ulcers had longer swing durations before milking (0.45 vs. 0.44 +/- 0.01 s, respectively). Gait differences were probably due to udder distention and motivation to return to the home pen. Our results suggest that the most suitable time to assess lameness is after milking when differences between cows with and without ulcers are most evident.

. 2010. Feeding behaviour of dairy cattle: Meaures and applications. Can. J. Anim. Sci. 90: 303Á309. There is growing scientific interest in feeding behaviour of dairy cattle, in part because dairy nutritionists are now becoming interested in how changes in feed intake are mediated by changes in behaviour and, in part, because changes in feeding behaviour are increasingly recognized as useful indicator of cow health. In this review we describe key methodological approaches to the study of feeding behaviour in dairy cattle. We also review empirical work addressing how changes in management and housing can affect this behaviour. We show how cows divide their daily intake into several discrete feeding events made up of a number of visits or ''meals'' that are separated by longer periods with little feeding activity. Feeding behaviour can be described using several measures, including the number and duration of meals, as well as intake and feeding rate. Feeding behaviour within a group of intensively managed cows is often highly synchronized, similar to that seen in extensively housed cattle, with delivery of fresh feed appearing to be the primary factor stimulating feeding by housed dairy cows. Competition at the feed bunk can affect feeding behaviour, increasing the feeding rate and reducing intake, especially for subordinate animals. We also review empirical work showing that feed intake, feeding times, and feeding rate are altered when cows are ill. Feeding behaviour changes in the days before calving, and these changes are greatest among cows at greatest risk of succumbing to disease in the early post partum period. These results suggest that monitoring changes in feeding behaviour may be useful in early detection and prevention of disease in transition cows. Les chercheurs s'inte´ressent de plus en plus aux habitudes alimentaires des bovins laitiers, en partie parce que les nutritionnistes souhaitent voir de quelle manie`re les changements de comportement affectent l'ingestion des aliments et en partie parce qu'on voit de plus en plus dans la modification des habitudes alimentaires un indicateur utile de la sante´de l'animal. Dans cet article, les auteurs de´crivent les principales approches me´thodologiques a`l'e´tude du comportement des bovins laitiers sur le plan de l'alimentation. Ils passent e´galement en revue les travaux empiriques indiquant de quelle manie`re les modifications au niveau des pratiques d'e´levage et du logement des animaux affectent ce comportement. Les auteurs montrent comment les vaches divisent leur alimentation journalie`re en segments compose´s de visites ou « repas » que se´parent de plus longues pe´riodes d'inactivite´. On peut de´crire les habitudes alimentaires en recourant a`diverses mesures, notamment le nombre et la dure´e des repas ainsi que le taux d'ingestion et d'alimentation. Dans les groupes de vaches laitie`res e´troitement e´leve´es, le comportement alimentaire s'ave`re souvent synchronise´, un peu comme cela se produit chez les bovins en claustration, l'arrive´e de n...

The existing guidelines for maximum sulfate (SO4) in cattle drinking water are based on Na2SO4, although many water sources contain greater concentrations of MgSO4. Two experiments compared the effect of different SO4 salts on water consumption and fecal DM of cattle. In Exp. 1, 8 yearling heifers (initial BW = 345 +/- 8 kg; mean +/- SD) were watered twice daily with tapwater or water containing Na2SO4 or MgSO4 at target levels of 1,500, 3,000, or 4,500 mg of SO4/L for 2-d treatment periods separated by 2 d of access to tapwater. In Exp. 2, 16 yearling cattle (initial BW = 421 +/- 24 kg) were watered twice daily with tap-water (16 mg of SO4/L) or water containing Na2SO4 at target levels of 2,000 mg of SO4/L (low Na2SO4), MgSO4 at 2,000 mg of SO4/L (low MgSO4), or MgSO4 at 4,000 mg of SO4/L (high MgSO4) in 21-d treatment periods separated by 7-d periods on tapwater. The first 10 d of each period were allowed for adjustment to the treatment, and the final 11 d was considered the treatment period for analysis purposes. Treatments were applied in an incomplete Latin square, where each animal was exposed to 3 of the 4 treatments. In Exp. 1, the average daily water consumption decreased linearly as the SO4 concentration increased for MgSO4 (P = 0.0001) but not for Na2SO4 (P = 0.39). In Exp. 2, the average daily water consumption was less for cattle on the high-MgSO4 treatment than for cattle on the low-MgSO4 treatment (P = 0.0001), and cattle on the low-MgSO4 treatment tended (P = 0.09) to drink less than those on the tap-water treatment. Fecal DM was greater for cattle on the high-MgSO4 treatment than for those on the low-MgSO4 treatment (P < 0.01). These findings indicate that cattle reduce their consumption of water containing high (> or = 4,000 mg of SO4/L) concentrations of MgSO4, even after a given time to adjust to the treatment; such reductions may be accompanied by an increase in fecal DM.

Carbon dioxide (CO2) is commonly used to kill rodents. However, a large body of research has now established that CO2 is aversive to them. A multidisciplinary symposium organized by the Swiss Federal Food Safety and Veterinary Office discussed the drawbacks and alternatives to CO2 in euthanasia protocols for laboratory animals. Dialogue was facilitated by brainstorming sessions in small groups and a “World Café”. A conclusion from this process was that alternatives to CO2 were urgently required, including a program of research and extension to meet the needs for humane killing of these animals. The next step will involve gathering a group of international experts to formulate, draft, and publish a research strategy on alternatives to CO2.