despite a shortage of animal feed in iran, cereal stubble is often underutilized due to agro-economic reasons. on the other hand, lambs fed with a conventional fattening ration deposit a considerable amount of fat; therefore, this experiment was conducted aimed at better utilization of cereal stubble and reducing the fat content of lamb carcasses. fat-tailed mehraban and ghezel ram lambs were p...

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 ...

Two hundred crossbred lambs were used to determine energy value and optimum inclusion level of field pea (Pisum sativum) in corn-based diets. In experiment one (Exp. 1), 100 crossbred lambs (33.9 ± 1.3 kg initial BW) were blocked by weight and sex (two blocks of ewe lambs per treatment; three blocks of ram lambs per treatment) and fed for 89 days. In experiment two (Exp. 2), 100 crossbred ram l...

Timed artificial insemination (TAI) is a very important tool for reproductive programs in small ruminants, providing synchronized inseminations and more efficient use of superior males. The objectives this study were to investigate the viability different breeding protocols under sub-optimal conditions out season, compare outcome TAI sheep with two semen extenders. Ewes (n=575) subjected estrou...

Abstract Fetal microchimerism has been detected in maternal tissues of humans and rodents during after pregnancy. Studies focusing on fetal DNA transfer to domestic animals are limited, especially sheep. ram was observed the circulation pregnancy, but it is not known if this chimerism persists soft parturition. The objectives exploratory study were to: 1) determine male detectable mature ewes p...

Several studies of large mammals report no direct reproductive costs for females. Individual heterogeneity may hide fitness costs of reproduction, but mothers could also transfer some costs to their offspring. Using data on 442 lambs weaned by 146 bighorn sheep (Ovis canadensis) ewes at Ram Mountain, Alberta, we studied how reproductive effort varied with environmental and maternal conditions. ...

Data collected on 3256 lambs born to Horro and Menz breed ewes single-sire mated to 71 rams at the International Livestock Research Institute (ILRI) Debre Berhan station between September 1992 and June 1996 were analysed for rates of survival and growth from birth to weaning. A significantly lower proportion of Menz lambs died before 1 year of age (28%) than the Horro lambs (59%). Least squares...

The effects of food quality, breed type and sex (ram and ewe) on lamb growth and carcass composition, and their changes throughout growth, were measured. The three breed types were Scottish Blackface (B; no. = 24), Suffolk (S; no. = 28) and their reciprocal crosses (X; no. 33). The lambs had free access to a nutritionally non-limiting food, H, or a bulky food, L. Each lamb was scanned using X-r...

There are numerous examples demonstrating that selection has greatly influenced phenotypes in wild-harvested species. Here, a significant reduction in horn size in trophy desert bighorn sheep rams over 30 years in a reintroduced population in Aravaipa Canyon, Arizona is documented. After examining the potential effects of a detrimental change in the environment, inbreeding depression, and hunte...

Production characteristics of white-faced rams have been systematically evaluated over a 140-d test in Wyoming since 1961. Individual test records ( = 4,240) from rams on test were analyzed to determine change over the past 52 yr. Although rams on test are not older, weight on and off test has increased ( < 0.001) since 1961. Weight off test increased 22.7 kg and contributed to an increase ( < ...