The number of lambs sold per ewe mated in the breeding flock has a considerable impact on sheep operation profitability. This depends primarily on fertility, prolificacy (# of lambs), and lamb survival, mothering ability, milk production of the ewe and lamb growth rate. Optimal reproduction does vary by environment and management system – some sheep operations don’t want a lambing rate over 200...

The number of lambs sold per ewe mated in the breeding flock has a considerable impact on sheep operation profitability. This depends primarily on fertility, prolificacy (# of lambs), and lamb survival, mothering ability, milk production of the ewe and lamb growth rate. Optimal reproduction does vary by environment and management system – some sheep operations don’t want a lambing rate over 200...

Breeding ewes to lamb at 1 yr of age can improve profitability for some production systems. The first objective of this study was to evaluate the effect of age and weight at breeding and total postweaning weight gain on reproductive performance of ewe lambs. The second objective was to compare the effects of weight and age variables in four major sheep breeds (Columbia, Polypay, Rambouillet, an...

A new mutation in the bone morphogenetic protein 15 (BMP15) gene (FecX allele) causing increased prolificacy in heterozygous (R+) and sterility in homozygous ewes has been recently described in Rasa Aragonesa, a low-prolificacy Mediterranean breed. The current study determined, first, the effect of this polymorphism on natural and eCG-induced ovulation rate (OR) and the effect of eCG dose on re...

two experiments were performed to determine the effectiveness of different progestogens contained in intravaginal devices, different doses of ecg and subsequent hcg treatment on the reproductive performance of estrus-induced mature lori ewes. in the first experiment, 88 ewes were allocated into two groups, and were treated with either fluorogestone acetate (fga) sponges or controlled internal d...

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, ...

One hundred and sixty adult ewes of the Chios breed were divided randomly into two groups. One group was used for breeding in spring (S) and the other in autumn (A). In both groups oestrous behaviour was detected once a day. Ovulatory activity, 7 d after oestrus, fertility, prolificacy, embryo mortality, birth weight of lambs and milk production were recorded. The percentage of ewes which exhib...

Follicular dynamics and the expression of candidate genes using real-time polymerase chain reaction (PCR) were compared during the oestrous cycle of pig breeds with high (commercial line; n=24) and low (local Brazilian Piau; n=21) ovulation rates and prolificacy. Gilts were killed on Days 0, 4, 10 and 18 of the oestrous cycle and visible ovarian follicles were classified by follicular diameter....

Prolificacy can directly impact porcine profitability, but large genetic variation and low heritability have been found regarding litter size among porcine breeds. To identify key differences in gene expression associated to swine reproductive efficiency, we performed a transcriptome analysis of sows' endometrium from an Iberian x Meishan F2 population at day 30-32 of gestation, classified acco...

Litter size is one of the most important economical traits in sheep breeding industry. In addition to minor genes, litter size is under the influence of major genes. Bone morphogenetic protein 15 (BMP-15), a member of the transforming growth factor beta (TGF-ß) superfamily, which is specifically expressed in oocytes, plays a dramatic role in sheep prolificacy. Reported mutations in this gene ca...