Behavioural changes associated with lameness in dairy cattle are often subtle, making lameness detection difficult. Objective and reliable methods of assessing weight distribution among the four limbs may be useful in the early detection of hoof injuries. To determine how cows redistribute their body weight among the four limbs in response to discomfort, I used a standing force platform with uncomfortable surfaces under either a single hoof (Exp. 1, n = 13 cows) or two hooves (Exp. 2, n = 15 cows). In control sessions, when all four hooves were on comfortable surfaces, cows in both experiments kept more weight on the front hooves than on the back hooves. In Experiment 1, when one of the back hooves was on an uncomfortable surface, cows removed weight from this hoof and redistributed the majority of this weight onto the contralateral back hoof but did not change the distribution of weight among the front hooves. When the uncomfortable surface was under a front hoof, cows placed less weight on that hoof and placed more weight on the contralateral front hoof and the ipsilateral back hoof. The variation in weight placed by the cows on both contralateral hooves increased when one of the hooves was on the uncomfortable surface. Cows in Experiment 2 placed more weight on the back hooves when both front hooves were on uncomfortable surfaces, though there was no change in weight distribution when both back hooves were on uncomfortable surfaces. This study demonstrates that dairy cows can alter their weight distribution to accommodate discomfort and that they adopt different standing behaviours depending on the location of discomfort. These results will help in the interpretation of data from force platforms for on- farm detection of lameness in dairy cattle. ii

Thesis

In this work, the effect of finishing diet (pasture- or mixed-diet) on lipid and protein oxidation in beef homogenates was evaluated. Oxidation was chemically induced by ferrous iron and hydrogen peroxide. Lipid and protein oxidation were respectively measured by determining TBA reactive substances (TBA-RS) and protein carbonyl groups (DNPH coupling method). Evaluation of the antioxidant status of meat was also performed by measuring vitamin E concentration and antioxidant enzyme activities: Superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase. Pasture-finishing mode of animals significantly protected lipids in meat from oxidation but diet mode did not affect protein oxidation. Concentration of vitamin E was higher in meat from pasture-fed animals. Different diets had opposite effects on SOD and GPx activities, pasture-finishing mode of animals increasing SOD activity but decreasing GPx activity. No significant effect of diet was noted on catalase activity. ?? 2003 Elsevier Ltd. All rights reserved.

Meat Science, volume 66, issue 2, pages 467-473

beef, catalase, charolais, glutathion peroxidase, grain, lipid oxidation, meat, pasture-feed, protein oxidation, sod, vitamin e

(Abstract not available.)

(Abstract not available.)

livestock and climate change in the near east regi

(Abstract not available.)

Farmland-Riparian Interface Stewardship Program, page 16

Because of the difficulties of providing water in winter in many areas of B.C. snow is sometimes considered as a water source. Research in Alberta has shown cows can substitute snow for water without any detrimental effects. A trial with calves fed hay and grain showed slightly less weight gain than calves with water. Although eating snow should require more energy than drinking water, these trials on cows and calves showed little differences. However, quality and quantity of snow is important: '10 to 12 inches of snow may have to be melted to get 1 inch of water' fluffy snow may be preferred by livestock but it has a low water content 'crusted' snow may be difficult for livestock to use .some areas may not have sufficient snow some winters' pens areas or small fields may not have sufficient clean snow to use.

(Abstract not available.)

Research Note 101, page 21

World communities are concerned about the impacts of a hotter and drier climate on future agriculture. By examining Australian regional livestock data on sheep, beef cattle, dairy cattle, and pigs, the authors find that livestock production will expand under such conditions. Livestock revenue per farm is expected to increase by more than 47% by 2060 under the UKMO, the GISS, and a high degree of warming CSIRO scenario. The existence of a threshold temperature for these species is not evident.

Animals, volume 1, issue 4, pages 343-365

adaptation, australia, climate change, livestock species

Enhancing the n-3 polyunsaturated fatty acid (PUFA) content of beef is important in view of the generally saturated nature of fatty acids in ruminant meats and the negative effect this can have on human health. This study examined the effects of different sources of dietary n-3 PUFA on the performance of steers and the fatty acid composition of m. longissimus thoracis muscle and associated subcutaneous adipose tissue. Animals were fed ad libitum on grass silage plus one of four concentrates (60:40 forage:concentrate on a DM basis) containing differing sources of lipid: Megalac (16:0), lightly bruised whole linseed (18:3n-3), fish oil (20:5n-3 and 22:6n-3) and a mixture of linseed and fish oil (1:1, on an oil basis). Diets were formulated so that total dietary oil intake was 6 %, approximately half of which was from the experimental test oil. Linseed feeding not only increased the levels of 18:3n-3 in muscle phospholipid from 9.5 to 19 mg/100 g muscle but also enhanced the synthesis of 20:5n-3, the level of which increased from 10 to 15 mg/100 g muscle. Linseed also increased the proportion of 18:3n-3 in muscle neutral lipid and in adipose tissue lipids by a factor of 1.64 and 1.75 respectively. Fish oil feeding doubled the proportion of 20:5n-3 and 22:6n-3 in muscle phospholipids. The proportion of 18:1 trans in muscle neutral lipid was higher on the n-3 PUFA diets than the control diet, 0.04 and 0.02 respectively. Despite the implied modification to rumen metabolism, lipid source did not affect feed intake, growth rate, cold carcass weight or carcass fatness, but carcass conformation score was higher on fish oil treatments (P < 0.05). However, total muscle fatty acid content was not different between treatments and ranged from 3.5-4.3 % of tissue weight. The increase in n-3 PUFA in the meat produced by feeding linseed or fish oil lowered the n-6:n-3 ratio but had little effect on the P:S ratio.

British Journal of Nutrition, volume 85, issue 1, pages 115-124

beef, fatty acids, health

Study on beef cattle value chain opportunities.

Summary of beef value chain project.

(Abstract not available.)

Modern Beef Production, pages 1-2