No abstract

Male Southdown sheep ranging in age from birth to near maturity (c. 28 mo) from genetic lines selected for about five generations for increased (n = 40) and decreased (n = 40) weightadjusted ultrasonic backfat depth were used to investigate patterns of change in muscularity and other composition characteristics. Measures of muscularity in terms of muscle depth relative to bone length were greater for the high-backfat line in anatomical areas around or beside the femur, tibia, total pelvic limb, humerus, and scapula, but not the radius/ulna. Levels of muscularity increased at a decreasing rate with increasing carcass weight from about 1 to 36 kg in all areas. Where there was a genetic line effect on muscularity, this tended to be greater at higher carcass weights, with minimal differences at birth. Muscle to bone ratios corresponding to these measures of muscularity showed similar patterns of change and line differences. Leg bone weight was higher for the low-backfat line; for the same femur length, a number of femur dimensions were greater for that line. Carcass length at a set weight was greater for the low-backfat line, and the allometric growth ratio (AGR) for length declined with increasing carcass A97072

Half carcasses of 18 Pietrain and 18 Large White female pigs were each dissected into 93 muscle units. An allometric analysis of the weight of these units relative to total muscle revealed increasing craniocaudal and distoproximal growth gradients, which were more pronounced in the Pietrain. The greater total weight of muscle, shown previously for the Pietrain at any given body weight over the range studied, was not due to higher muscle weights in any particular region at birth, but at 60 kg body weight was due to heavier high impetus muscles. Heart weight relative to total muscle weight was higher for the Large White over the entire range. It is concluded that for the animals studied the changes in muscle distribution are related to the functional demands of an increase in body size, and that the muscle distribution of pigs can differ between breeds.

SUMMARY A horse with rostral displacement of the palatopharyngeal arch was found to have a bilaterally symmetrical deformity of the laryngeal area. Both left and right cricopharyngeal muscles were absent. The shape of the thyroid cartilage was grossly abnormal and vestiges of the cricothyroid muscles were attached only to the cricoid cartilage. It was suggested that such an anomaly could have resulted from aberrant development of the fourth branchial arch. RÉSUMÉ Un cheval présentait un déplacement rostral de l'arc palato‐pharyngien. Il présentait également une déformation bilatérale et symétrique de la région laryngée. Les muscles crico‐pharyngiens droit et gauche étaient absents. La forme du cartilage thyroïde était anormale et des vestiges des muscles crico‐thyroïdiens étaient insérés sur le cartilage cricoïde. Une telle anomalie peut résulter d'un développement perturbé du 4ème arc branchial. ZUSAMMENFASSUNG Ein Pferd mit einer Verlagerung des Gaumen‐Rachen‐bogen nach rostral wies eine bilateral symmetrische Deformation der Larynxgegend auf. Die beiderseitigen Cricopharyngealmuskeln fehlten. Die Gestalt des Thy‐roidknorpels war stark verändert und Ueberreste von Cricothyroidmuskulatur fanden sich nur am Cricoid‐knorpel befestigt. Es wird vermutet, dass sich eine derartige Anomalie aus einer Fehlentwicklung des vierten Kiemenbogens ergeben haben könnte.

An anatomical study compared the effects of sex and a twofold nutritional difference in growth rate between 20 and 100 kg live weight, on 63 entire males, castrated male and female Large White x Landrace pigs. While the effect of growth rate was significant for overall fat deposition in the carcasses of all three sexes, it was greatest for the entire male. In contrast, sex and nutritional effects on the distribution of fat and on the proportion and distribution of muscle and bone were small.