Influence of sex hormones on the subcellular distribution of copper in sheep liver.

At the 14th to 16th week of pregnancy the copper content in the maternal liver was low while that in the fetus was high. After ovariectomy there was a decrease in liver copper and ceruloplasmin which was prevented by treatment with oestrogens but not with progesterone. Five groups of sheep were studied: control (barren ewes), pregnant, ovariectomised and ovariectomised treated with oestrogens or progesterone. In all, with high or low liver copper, the nuclear fraction contained the most copper. This suggests a species specificity of the copper metabolism in sheep.

Effects of bovine somatotropin and thyroid hormone status on hormone levels, body weight gain, and mohair fiber growth of Angora goats.

Forty-eight Angora goats (24 wethers and 24 doelings; 5 mo old; 16 +/- 0.5 kg initial BW) were used in an experiment with a 2 x 3 factorial treatment arrangement (n = 8) to evaluate effects of recombinant bovine somatotropin (bST) administration and thyroid hormone status (euthyroid, hypothyroid, and hyperthyroid) on hormone levels, ADG, and mohair fiber growth. The bST was a slow-release zinc-based suspension, with sustained delivery (100 microg/[kg BW x d]) over a 14-d period. Hyperthyroidism was maintained by daily treatment with thyroxine (T4; 150 microg/[kg BW x d]), and hypothyroidism was achieved by feeding 6 mg/(kg BW x d) of propylthiouracil. The experiment was conducted in July to September and consisted of a 2-wk pretreatment period and 8 wk of bST treatment. Goats were given ad libitum access to a diet with 15% CP and 2.54 Mcal/ kg ME (DM basis). Concentrations of T4 and T3 were greatest (P < 0.01) among treatments for hyperthyroid-bST and hyperthyroid-control (T4: 38.6 and 38.0 microg/dL; T3: 406 and 385 ng/dL, respectively); similar among euthyroid-control, euthyroid-bST, and hypothyroid-bST (T4: 11.1, 11.5, and 9.8 microg/dL, respectively; T3: 232, 252, and 226 ng/dL, respectively); and lowest (P < 0.01) for hypothyroid-control (T4: 5.1 microg/dL; T3: 144 ng/dL). Plasma concentration of insulin-like growth factor-I was greatest (P < 0.01) for euthyroid-bST (596 ng/mL) and hypothyroid-bST (618 ng/mL); however, concentration for hyperthyroid-bST was similar to those for euthyroid-control, hypothyroid-control, and hyperthyroid-control (188, 178, 187, and 191 ng/mL, respectively). Dry matter intake was greatest (P < 0.05) for euthyroid-bST (794 g/d), similar among hypothyroid treatments (693 and 703 g/d for control and bST, respectively) and euthyroid-control (681 g/d), and lowest for hyperthyroid groups (554 and 518 g/d for control and bST, respectively); ADG for hyperthyroid goats (11 g/d) was lower than with hypothyroidism and euthyroidism (72 and 73 g/d, respectively); and mohair fiber growth was greater (P < 0.01) for hyperthyroidism (0.133 g/[100 cm2 x d]) than for hypothyroid and euthyroid goats (0.102 and 0.104 g/[100 cm2 x d], respectively). Hyperthyroidism also increased mohair length growth rate by 15% and decreased fiber diameter by 7.8% (P < 0.01). These results demonstrate interactions between growth hormone administration and thyroid hormone status, although these influences had limited effects on ADG and mohair fiber growth.

Effects of dietary protein concentration on postweaning growth of Boer crossbred and Spanish goat wethers.

Boer (3/4) x Spanish (1/4) (BC; n = 23) and Spanish (SP; n = 22) goat wethers, 4 to 4.5 mo of age and 17.6 and 19.4 kg initial BW, respectively (SE = 0.57), were used to determine effects on growth of protein concentration in 70% concentrate diets provided for ad libitum intake for 30 wk in confinement. Offered diets contained 10.2, 14.2, 18.3, and 23.6% CP (DM basis), and CP concentration in consumed DM was 9.3, 13.8, 17.1, and 22.1% (P1, P2, P3, and P4, respectively); supplemental protein was from soybean meal for P1 and P2 and from soybean meal plus a blend of blood, fish, and feather meals for P3 and P4. Dry matter intake was similar between breeds and among diets (732, 712, 698, and 740 g/d for P1, P2, P3, and P4, respectively; SE = 27.0). Average daily gain was greater for P2 (P = 0.07) and P4 (P < 0.05) than for P1 (76, 90, 85, and 100 g/d for P1, P2, P3, and P4, respectively; SE = 5.3) and for BC than for SP (97 vs 78 g/d, SE = 3.7; P = 0.05). Similarly, ADG:DMI was lowest (P < 0.05) among diets for P1 (0.106, 0.126, 0.121, and 0.132 for P1, P2, P3, and P4, respectively; SE = 0.0053) and greater (P < 0.05) for BC than for SP (0.135 vs 0.108; SE = 0.0037). In conclusion, with 70% concentrate diets, the protein requirement for both BC and SP seemed to have been met by consumption of diets with at least 14% CP, with no apparent benefit from addition of ruminally undegraded protein.

Fatty acid composition of goat muscles and fat depots: a review.

In addition to the fat content of muscle and adipose depots, the fatty acid composition of lipids affects meat quality. Furthermore, relevant reports are difficult to use for comparisons, in that samples were collected from muscles and fat depots at various anatomical locations and experiments entailed different objectives, designs, procedures and methodologies. Nonetheless, based on currently available publications, according to a recent classification of meats by concentrations of potentially cholesterol-raising, and neutral, and cholesterol-lowering effects, average values for goat muscles appear better than for beef and lamb. Feeding dry diets seems to increase levels of unsaturated fatty acids and stearic acid in fat depots compared with milk or milk replacer. Increasing concentrate consumption can increase levels of odd-numbered and branched chain fatty acids in subcutaneous fat depots. With increasing age of unweaned kids, the level of stearic acid in fat depots decreases, and with increasing live weight of weaned kids levels of saturated fatty acids increase, and contents of monounsaturated fatty acids decrease in most fat depots. This review of a currently limited database indicates need for further experimentation to characterize interactions among factors such as breed, age and nutritional conditions in the fatty acid composition of carcass lipids of goats so as to gain a fuller understanding of goat meat quality.