A study involving 825 spring ewe lambs was conducted to evaluate effects of breed, heterosis, type of birth and rearing, age of dam and preweaning and postweaning growth rate on occurrence of puberty before November 10. Within a breed or breed-cross, preweaning competition among twin and triplet lambs reduced lamb weights by 4 or 5 kg at 70 (weaning), 160 and 230 days of age and by about 3 kg a...

Sources of variation in Finnish Landrace and Targhee birth weights from pregnancies following natural matings and intra-breed, inter-breed and 2-breed embryo transfers were studied. Birth weights were recorded on 94 lambs from naturally mated ewes and 117 transfer lambs. Two analyses were done, one on observed weights, and one on deviations of observed weights from weights predicted from litter...

Total litter weight weaned at 120 d postpartum per ewe lambing is often believed to be a measure of range ewe productivity. Genetic correlations for litter weight weaned at 120 d with prolificacy, growth, and wool traits for Columbia, Polypay, Rambouillet, and Targhee sheep were estimated using REML with animal models. Observations per breed ranged from 5,140 to 7,083 for litter weight weaned, ...

The aim of this study was to determine the effect of ewe breed on the reaction time and semencharacteristics in the ram. For this purpose, from the native sheep breeds in Iran, seven Lory rams and fourewes (two Lory and two Ghezel breeds) were selected. Seven rams were individually subjected to 4 weeklytrials in which one of the following two treatments was applied alternately. All of rams were...

Multiparous Suffolk and Suffolk-cross ewes were randomly allotted to treatments within breed and year to measure effects of ram exposure, during transition from anestrus to breeding activity, on reproductive performance. Treatments were: 1) ewes joined with two mature vasectomized Rambouillet rams for 15 d before breeding (DC), 2) ewes maintained across a net wire fence from two vasectomized ra...

early weanling and rearing of lambs on milk replacer is an important act to increasing flock productivity. two experiments were carried out to compare the voluntary intake and nutrients digestibility ewe milk and commercial milk replacer and their feeding effects on the growth rate, feed intake and feed efficiency of suckling lambs. in experiment 1, eight lambs (two 4-lamb groups) at 31 to 34 d...

Rams express differences in sexual performance during the breeding season. Breeding rams with high sexual performance scores as measured during a sexual performance test can improve flock fertility. Whether selecting rams for high sexual performance score will indirectly improve ewe reproductive performance is not known. The objective of this study was to estimate the genetic correlation betwee...

Reproductive traits from 7642 ewes were recorded from 1975 to 1983. The ewes were of five breeds (Dorset (D), Finnsheep (F), Rambouillet (R), Suffolk (S) and Targhee (T)) and two composite lines [C1 (1=2F þ 1=4R þ 1=4D) and C2 (1=2F þ 1=4S þ 1=4T)]. Genetic parameters were estimated for six basic and seven composite traits. The basic traits were conception rate (CR), total number of lamb born (...

Tuj sheep, a well adopted breed for the geography and climate of the highlands, originated in the Caucasus and are found throughout the northeast of Turkey. Although the mature sheep are able to reproduce normally at these conditions, ewe-lambs are normally not able to reach puberty during the first year of their life. Shortage in feed due to long and cold winters together with the seasonality ...

Lifetime production of first-generation 1/4 and 1/2 Finnsheep crossbred ewes from Rambouillet (R), Targhee (T) and Columbia (C) dams was compared with that from randomly selected purebred R, T and C ewes. All 1,190 ewes, representing nine breed groups, were managed under range conditions and mated annually to Suffolk rams. Lifetime production was evaluated as the total lamb and total wool produ...