Stepping behavior and muscle activity of dairy cattle standing on concrete or rubber flooring for 1 or 3 hours.

The type of flooring in dairy cattle systems influences cows' health and welfare. Although concrete is common, the use of more compressible flooring, such as rubber, is increasing. Cows prefer to stand and walk on rubber surfaces than on concrete; however, it is largely unknown how walking and standing for longer periods of time influence muscle activity and fatigue. Therefore, we used measures of behavior and muscle activity to investigate the potential benefits of providing a rubber flooring surface to dairy cattle. Sixteen lactating Holstein cows were forced to stand on either concrete or rubber flooring for 1 or 3 h in a 2 × 2 crossover design. Surface electromyograms (SEMG) and skin surface temperature were used to evaluate muscle activity, fatigue, and movement of muscle activity between the hind legs. Activity of 2 muscles, the bicep femoris and middle gluteal, was assessed during both static contractions, when cows transferred weight to each hind leg, before and after 1 and 3 h of standing, and dynamic contractions, associated with steps and with shifts in weight without steps. In addition, we evaluated stepping rate, time between each step, feeding behavior, skin surface temperature, and latency to lie down after standing. Standing duration influenced both the behavior and muscle activity of cows. Stepping rate increased with standing time for cows on both flooring types. Static muscle activity parameters of the bicep femoris muscle were higher after 3 h of standing for cows standing on both flooring types (2.3 and 3.6% increases in median amplitude and median power frequency, respectively) compared with the change after 1 h and compared with baseline values before the standing treatment. Flooring type influenced the behavior and muscle activity of the cows, particularly during the first hour of exposure; cows standing on rubber had a higher stepping rate, shorter interval between steps, and higher number of SEMG shifts (muscle activity shifts with or without visible steps) than cows on concrete. There was no difference in skin surface temperature, feeding behavior, or latency to lie down between the treatments. The results show that standing on a rubber flooring caused a different initial behavioral response compared with standing on concrete; however, possible reasons for these changes are unclear. Standing for 3 h resulted in an increase in stepping rate and in some muscle activity parameters; however, the results regarding muscle fatigue in relation to flooring type are inconclusive.

Domestic cattle (Bos taurus taurus) are motivated to obtain forage and demonstrate contrafreeloading.

Domestic cattle (Bos taurus taurus) are adapted to digest high-roughage diets, but in confinement they are commonly fed low-roughage, high-energy diets. This practice may leave cattle with an unfulfilled need to consume forage. A way to quantify motivation is to require animals to work to access a resource. Using this method, we evaluated cattle motivation to obtain forage when fed high- or low-roughage diets during and 30 d before the study. Individual heifers were fed Sudan grass (Sorghum × drummondii) hay (high roughage, n = 6) or a diet with 12% forage (as fed, low roughage, n = 6) in an open feed trough. In a second trough, 200 g/d of Sudan grass hay were fed behind a push gate, to which additional weight was added daily until heifers no longer pushed. We predicted heifers would push heavier weights, show a shorter latency, and spend more time pushing the gate when fed a low- vs. high-roughage diet. Indeed, heifers fed a low-roughage diet pushed the gate immediately after hay delivery (1.7 min) and much sooner than those fed a high-roughage diet (75.7 min). On the day before they no longer pushed the gate, latency for heifers in the low-roughage treatment remained only 3.2 min after hay delivery. The suddenness with which they ceased pushing the next day suggests they were unable to move heavier weights to express their motivation. This may explain why maximum weight pushed and time spent pushing the gate did not differ between treatments. The gate pushing by heifers with unrestricted hay access is the first demonstration by cattle of contrafreeloading: performing work to obtain a resource that is simultaneously available for free. In conclusion, consuming forage is important to cattle and is affected by both their primary diet and an internal motivation to work to obtain feed.

The age of surgical castration affects the healing process in beef calves.

Castration is painful for calves. Castrating at an earlier age is often recommended, but little is known about how this affects the healing process or the pain experienced. We compared incision closure, swelling and pain sensitivity of beef calves surgically castrated at 3 (range 0 to 8 d; n = 16) or 73 (range 69 to 80 d; n = 15) d of age. Closure of the incision, as measured with a 5-point scale (1 = fresh wound, 5 = no longer visible), weight gain, and inflammation (skin temperature and swelling, as measured by scrotal circumference) were recorded on d 1, 3, 7, 11, 15, 18, 21, 25, 32, 39, 45, 61, and 77 after the procedure, until all incisions were fully healed. On these same days, pain sensitivity was assessed by applying a known and increasing force with von Frey hairs (0.02 to 300 g-force) at the edge of the castration wound and at a control site, approximately 2 to 5 cm anterior to the teats, until animals showed a behavioral response or the highest force was reached. The incisions of younger calves healed more quickly than older ones [fully healed, median (95% confidence interval); 39 (32 to 61) vs. 61 (61 to 77) d; P = 0.002], however, they had relatively more swelling in the days after castration (P < 0.001). Younger animals reacted to lighter pressure of von Frey hairs compared to older calves especially in the first stages of healing process (P < 0.001), and there were other signs indicative of inflammation processes in this region at this time. However, there was no difference in the control site for either age group. In addition, it took longer for older calves to recover their daily weight gain after the procedure (P < 0.001). Taken together, these results paint a mixed picture about the effects of age of surgical castration. Calves castrated soon after birth experience more tissue swelling and show more signs of pain, but their incisions heal sooner and their weight gain is less affected, when compared to animals castrated around 73 d of age.