Sexual activity, body size and testis growth in the prepubertal period (120-210days of age) were studied in five male lambs of each of four dairy sheep breeds. Sexual responses developed earlier in Friesland than in Chios and Karagouniki and latest in Serres ram lambs. Friesland lambs expressed interest in females at 127days of age and 34kg live weight 18-36days younger and 3.4-6.3kg lighter th...

Variance components for birth, weaning, yearling and final weight in Australian Hereford, Angus and Zebu Cross cattle were estimated by Restricted Maximum Likelihood. Six different animal models were fitted for each trait and breed, ranging from a simple model with animals as the only random effect to the most comprehensive model allowing for both genetic and environmental maternal effects and ...

This study was designed to determine the testicular abnormalities in rams slaughtered Sokoto, Nigeria. The testicles of presented for slaughter were examined, and age, breed, position, sites noted. Out 638 3 had abnormalities, representing a prevalence 0.47%, comprising 2 (0.31%) unilateral cryptorchidism 1 (0.16%) hypoplasia. (0.58% (2/342) 0.34% (1/296) obtained at Sokoto metropolitan abattoi...

The differences of fertility and prolificacy traits for Rahmani and Chios ewes were studied in this investigation. The study was conducted during two consecutive years that included three lambing season with a total of 273 ewes (162 Rahmani and 111 Chios) bred, 230 ewes lambing, 280 lambs born and 237 lambs weaned. Breed of ewes had a significant effect on fecundity, lambing rate and weaning ra...

To determine the effect of breed on copper status of crossbred (F1) lambs, a study was conducted using 187 crossbred wether lambs. Wether lambs were progeny of five ram breeds (Dorset, Finnsheep, Montadale, Romanov, and Texel) and two ewe breeds (Rambouillet and a composite breed [1/2 Columbia, 1/4 Suffolk, 1/4 Hampshire]). Diets were adjusted to decrease crude protein twice during the experime...

Twenty Polypay-sired ewes (Group P) and 14 Suffolk ewes (Group S) were bled at 48-h intervals for 10 d beginning on April 6, 1989, and the serum was assayed for progesterone to determine which ewes were anestrous; 9/20 Group P ewes were anestrous, compared with 14/14 Group S ewes (P less than .001). Catheters were placed into the jugular vein of anestrous ewes from both breed groups (eight of G...

Two groups of purebred ewes (A and B), each consisting of 25 Dorsets and 25 Hampshires, were used to study effects of ewe breed and ram exposure on ovulation and estrus in May and June. Ewes lambed in January and February and were isolated from mature rams for at least 5 mo. From May 8 to June 11 (Period 1), Group A ewes were penned with vasectomized rams fitted with marking harnesses and Group...

The aim of this thesis was to study potential breeding strategies for indigenous livestock in Eastern and Southern Africa under low input production systems. The thesis covered a study of the status of supportive infrastructure for use of animal genetic resources. The case of Red Maasai sheep was studied as a model for design of strategies for improvement of an indigenous breed under threat. St...

Ewe productivity is synonymous with annual litter-weight weaned (LWW) per ewe exposed to rams for breeding, and LWW is largely a function of number of lambs born (NLB) and weaned (NLW). Selecting for LWW should increase litter size and numbers of ewe-ram co-twins. Thus, we used historical records to determine whether sex of co-twin affected lifetime productivity of twinborn ewes. United States ...

A comparative slaughter trial was conducted to estimate the phosphorus (P) requirement for maintenance and growth of crossbred lambs of Dorper with a Chinese indigenous sheep breed, thin-tailed Han sheep. Thirty-five Dorper×thin-tailed Han crossbred, noncastrated ram lambs (20.3±0.22 kg of shrunk body weight (SBW)) were used. Seven lambs were randomly chosen and slaughtered at 20 kg SBW as the ...