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Greater rates of genetic gain can be achieved by selecting animals born to younger parents. However, little is known about the lifetime performance of dual purpose ewes (Ovis aries) that are born to primiparous ewe lambs (8 to 9 months old at breeding). This experiment investigated the effect of being born from either a ewe lamb or mixed age dam as either a single or twin on the lifetime performance of ewe progeny. Lifetime performance was measured in terms of the life time live weights of the ewes, the weight and number of lambs born and weaned, the efficiency of production (kilograms of lamb weaned / predicted pasture intake (kgDM) of the ewes), and ewe survival. The study followed the lifetime production of 17 single and 41 twin female lambs born to mature ewes (M1 and M2, respectively), and 28 single and 29 twin lambs born to ewe lambs (L1 and L2, respectively). Over their lifetime L2 ewes were lighter (P<0.05) but had similar body condition scores to the other three ewe groups. There was no difference in average progeny weaning weight or total progeny litter weaning weights between groups. The M1 ewes had the greatest longevity (P<0.05) of the four groups. Even though L2 ewes were lighter than the other three groups, this was insufficient to increase their lifetime efficiency of production (kg lamb weaned/predicted pasture consumption), relative to the other groups. These results suggest farmers could select replacements born to ewe lambs without sacrificing animal production.
This article was published in the following journal.
Name: PloS one
This trial evaluated the individual and interactional effects of diet and type of pregnancy (twin or single) on plasma metabolic response in ewes and their lambs from late pre-partum to late post-part...
Twins with discordant growth have increased risks of perinatal mortality and morbidity. Previous studies have identified a number of risk factors for inter-twin birth weight discordance, yet no study ...
Although the impact of gestational weight gain (GWG) on birth weight in twin pregnancies has been demonstrated, the specific components of GWG have not been delineated for twin gestations. Fetal body ...
In twin pregnancies, which are at high risk of preterm birth, it is not known if maternal clinical characteristics pose additional risks. We undertook a systematic review to assess the risk of both sp...
To determine whether assumptions used in prenatal screening for Down syndrome in twin pregnancies are valid, and derive estimates of risk and screening performance in twin pregnancies using observed d...
For twin pregnancies at 32-38 weeks gestation, where twin A is head down, does a policy of planned caesarean section (CS) lower the likelihood of death or serious illness, during the first...
This study will be the first study that evaluates the effectiveness of antenatal corticosteroid (ACS) in late preterm twin neonates.
Hypothesis: Among women with twin or triplet pregnancies, weekly injections of 17-alpha-hydroxyprogesterone caproate (17OHP), started before 24 weeks of gestation, will reduce neonatal mo...
The 2-BIG is a twin birth cohort study located in Guangzhou, China.Its initial aim is to facilitate research on understanding the interplay between genes and environmental factors on disea...
This is a multicenter randomized study designed to determine if physical exam indicated cerclage reduces the incidence of spontaneous preterm birth
Methods of detecting genetic etiology in human traits. The basic premise of twin studies is that monozygotic twins, being formed by the division of a single fertilized ovum, carry identical genes, while dizygotic twins, being formed by the fertilization of two ova by two different spermatozoa, are genetically no more similar than two siblings born after separate pregnancies. (Last, J.M., A Dictionary of Epidemiology, 2d ed)
Passage of blood from one fetus to another via an arteriovenous communication or other shunt, in a monozygotic twin pregnancy. It results in anemia in one twin and polycythemia in the other. (Lee et al., Wintrobe's Clinical Hematology, 9th ed, p737-8)
A performance test based on forced MOTOR ACTIVITY on a rotating rod, usually by a rodent. Parameters include the riding time (seconds) or endurance. Test is used to evaluate balance and coordination of the subjects, particular in experimental animal models for neurological disorders and drug effects.
Either a single or a single functioning kidney due to NEPHRECTOMY, birth defects or other kidney diseases.
A secreted member of the TNF receptor superfamily that negatively regulates osteoclastogenesis. It is a soluble decoy receptor of RANK LIGAND that inhibits both CELL DIFFERENTIATION and function of OSTEOCLASTS by inhibiting the interaction between RANK LIGAND and RECEPTOR ACTIVATOR OF NUCLEAR FACTOR-KAPPA B.