Brand TS, Franck F
Elsenburg Agricultural Research Centre, Private Bag X1, 7607, Elsenburg, South Africa
Small Rumin Res. 2000 Jul 1;37(1-2):85-91. doi: 10.1016/s0921-4488(99)00126-1.
The primary selection objective in the South African Mutton Merino is meat production, while wool plays a secondary role. The Merino, on the other hand is selected for wool production. Respectively 20 and 23 of each genetic different type of ewes were used in a 15-week indoor study to quantify the influence of nutrient intake on certain production traits when fed at different levels of their respective requirements during late pregnancy (last 6 weeks) and lactation (first 6 weeks). Results were used to provide production parameters for the two types of ewes and their lambs at different levels of nutrition. Lambing percentage (per ewe lambed) of SA Mutton Merino ewes was 171% compared to 135% for Merino ewes. Live weight gains for meat-wool and wool-type ewes during late pregnancy amounted to 15.9 and 21.9%, with corresponding live weight losses of -8.3 and -1.1% during the first 6 weeks of lactation. Greasy wool production during the last 9 weeks of pregnancy and the first 6 weeks of lactation amounted to 1.57kgewe(-1) (meat-wool type ewes) and 2.84kgewe(-1) (wool-type ewes). Milk production 17 days post partum was 2.33kg/day and 1.84kg/day for the two types of sheep. Lambs of the meat-wool type ewes had a mean birth weight of 4.1kg and an average daily gain (ADG) of 270g/day to 42 days of age. Lambs of the wool-type ewes had a mean birth weight of 4.9kg and a 42-day ADG of 192g/day. There were clear differences in production traits of the two types of Merino sheep, which were in accordance with their genetic differences. The study gave practical production norms for meat-wool and wool-type Merino ewes and their lambs when subjected to different nutritional levels.
南非肉用美利奴羊的主要选育目标是产肉，羊毛则起次要作用。另一方面，美利奴羊是为产毛而选育的。在一项为期15周的室内研究中，分别选用了20只和23只不同基因型的母羊，以量化在妊娠后期（最后6周）和哺乳期（前6周）按照各自不同需求水平饲喂时，营养摄入量对某些生产性能的影响。研究结果用于提供两种母羊及其羔羊在不同营养水平下的生产参数。南非肉用美利奴羊母羊的产羔率（每只产羔母羊）为171%，而美利奴羊母羊为135%。肉毛兼用型和毛用型母羊在妊娠后期的体重增加分别为15.9%和21.9%，在哺乳期的前6周相应的体重损失分别为-8.3%和-1.1%。妊娠最后9周和哺乳期前6周的污毛产量分别为1.57千克/只（肉毛兼用型母羊）和2.84千克/只（毛用型母羊）。产后17天两种羊的产奶量分别为2.33千克/天和1.84千克/天。肉毛兼用型母羊所产羔羊的平均出生体重为4.1千克，到42日龄时平均日增重（ADG）为270克/天。毛用型母羊所产羔羊的平均出生体重为4.9千克，42日龄时的平均日增重为192克/天。这两种美利奴羊的生产性能存在明显差异，这与它们的遗传差异相符。该研究给出了肉毛兼用型和毛用型美利奴母羊及其羔羊在不同营养水平下的实际生产标准。
