The effects of depriving feed to facilitate transport and slaughter in sheep--a case study of cull ewes held off pasture for different periods.

AIM: To determine the ability of sheep to mobilise their body reserves after being deprived of feed prior to transport for slaughter. METHODS: A total of 240 3- and 4-year-old cull ewes were held off pasture for 0, 9, 18 or 30 hours (n=60 per group) then transported 1 hour by road, unloaded and washed, held in lairage for 3 hours then slaughtered. Blood samples were collected from a subsample of 60 unfasted ewes 1 week earlier, and from all ewes at exsanguination to determine concentrations of serum metabolites indicative of adaptation to fasting. In addition, several attributes of carcass quality were measured. RESULTS: At slaughter, increased time off pasture prior to transport resulted in no change in glucose concentrations in serum (p=0.140). There were differences (p<0.001) between the group fasted for 30 compared with 0 hours in mean concentrations of free fatty acids (0.98 (SD 0.32) vs. 0.58 (SD 0.23) mmol/L), ß-hydroxybutyrate (0.69 (SD 0.17) vs. 0.42 (SD 0.11) mmol/L), triglycerides (0.29 (min 0.13, max 0.83) vs. 0.22 (min 0.06, max 0.96) mmol/L) and urea (10.17 (SD 1.80) vs. 6.94 (SD 2.03) mmol/L). Different periods of feed deprivation had no effect (p>0.05) on carcass weights (mean 22.7, min 13.2, max 32.9 kg) or dressing out percentages (mean 40.9, min 27, max 49%). Meat ultimate pH was unaffected (p>0.05) by the period of feed deprivation but meat became darker (p<0.05) and had reduced redness (p<0.001) with increasing time off feed. CONCLUSIONS: The results suggest that sheep in variable body condition adapted to the periods of feed deprivation by mobilising their energy reserves without any evidence of metabolic depletion (e.g. depleted blood glucose or high meat pH). However, being deprived of feed they probably experience a degree of hunger.

The role of the scapula in the rehabilitation of shoulder injuries.

OBJECTIVE: To present a clinical understanding of the role the scapula plays in the mechanics of shoulder function and specialized techniques for the rehabilitation of injuries around the shoulder girdle. BACKGROUND: The scapular musculature is often neglected in the evaluation and treatment of shoulder injuries. This lack of attention often degenerates into the incomplete evaluation and rehabilitation of scapular dysfunction. Dysfunction or weakness of the scapular stabilizers often results in altered biomechanics of the shoulder girdle. The altered biomechanics can result in (1) abnormal stresses to the anterior capsular structures, (2) the increased possibility of rotator cuff compression, and (3) decreased performance. DESCRIPTION: We review the anatomy and role of the scapula, the pathomechanics of injury and dysfunction, and the evaluation and rehabilitation of the scapula. CLINICAL ADVANTAGE: Knowledge of how the scapular muscles influence function at the shoulder builds a strong foundation for the clinician to develop rehabilitation programs for the shoulder.

Post-mortem kinetics of meat tenderness and the components of the calpain system in bull skeletal muscle.

Eight strip loins (M. longissimus dorsi) from pasture fed Friesian bulls were aged at 15 °C for a range of times from 1 to 120 h. pH declined from 6.29 (SE 0.119) one hour post slaughter to an ultimate pH of 5.48 (SE 0.013). The activities of the components of the calpain system (µ-calpain, m-calpain and calpastatin) were determined after separation on a DEAE-sephacel column. There was a dramatic decline in µ-calpain activity post slaughter with a complete disappearance within 48 h. The rates of decline in m-calpain and calpastatin activity were slower with 30% and 50% remaining 120 h post slaughter, respectively. The rapid decline in µ-calpain activity relative to the calpastatin activity is likely to reduce the degree of tenderisation and ultimate tenderness of the meat.

Sexual dimorphism in the growth response of entire and gonadectomized rats to clenbuterol.

This study compared the anabolic effects of clenbuterol in male and female rats and determined the relative contribution of testicular and ovarian hormones to any observed gender difference. Seventy-two 12-wk-old rats were used in a 2 x 2 x 2 factorial design in which animals were either male or female, entire or gonadectomized at 3 wk of age, and fed either a control diet or a diet containing 4 mg clenbuterol/kg feed for 8 days. Compared with entire male rats, entire females gained 64% less weight, had lighter carcasses (-36%) and gastrocnemius muscles (-62%), and had higher plasma concentrations of the catabolic hormone corticosterone (P < 0.05). Castration had a negative effect on growth in male rats, and ovariectomy had a positive effect in females, but there was still a gender difference in body weight between gonadectomized males and females, which amounted to 34% of the gender difference observed in intact rats. The density of beta 2-adrenoceptors in skeletal muscle was not different between males and females, nor was it affected by gonadectomy. Clenbuterol increased both weight gain and gastrocnemius muscle weight, with the latter response in entire and castrated male rats (+ 1.31 and + 1.17 g) being more than double that seen in entire and ovariectomized females (+ 0.58 and + 0.55 g). The downregulation response of beta 2-adrenoceptors in this muscle was remarkably consistent in all treated groups (-50% to -53%).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of genotype and nutrition on calpastatin inhibitory activity and mRNA abundance in milk-fed lambs.

Muscle proteolysis is controlled by a wide range of enzyme systems. The reported effects of the calcium dependent proteinases (calpain I and II) and its specific inhibitor (calpastatin) on myofibrillar structure, has led to the speculation that this system may have a pivotal role in regulating protein turnover and muscle growth. The present study highlights the possibility of protein degradation being subject to genetic variation. The relationship between genotype, level of nutrition, muscle protein turnover and the calpain system in young milk-fed lambs was assessed. Male lambs which had been selected for 10 generations for high (W+) and low (W-) weight at weaning were used in the study. Lambs were removed from their mothers 4 days after birth and surgically fitted with abomasal catheters and infused with reconstituted milk replacer at a high or a low rate. At 8 weeks of age, measurements of muscle protein gain, synthesis and degradation were performed, the animals were slaughtered and samples rapidly removed for subsequent chemical analysis. The liveweight gain and weight of the m vastus lateralis was reflected (P < 0.001) in the designed differences in nutrient supply. The weight of the m vastus lateralis was greater (P < 0.01) in the W+ compared to the W- lambs. The rate of protein synthesis and calculated degradation were greater (P < 0.05) in W+ than W- lambs. Calpain I and II and calpastatin activity were not significantly altered by genotype or nutrition. Calpastatin mRNA abundance increased significantly (P < 0.05) between 1 and 8 weeks of age. Regression analysis revealed genotype-specific responses with respect to calpastatin activity and mRNA abundance.(ABSTRACT TRUNCATED AT 250 WORDS)