A series of simulations were performed to evaluate the effects of mature size (WMA; 60, 70, 80 and 90 kg), slaughter weight (SW; 55, 60 and 65 kg) and three diets fed to feedlot lambs. Rations included a traditional diet (C2L) or placing weaned lambs on alfalfa for either 30 (A30) or 60 (A60) d before placing them on the C2L diet (A30-C2L and A60-C2L). Two lamb pricing schemes were used in the ...

The objectives were to study the relationship between in vivo ultrasound measurements and cold carcass measurements at 4 anatomical points along the backbone of lambs and to determine appropriate regression equations to estimate carcass composition by using ultrasonic measurements at each anatomical point. The lambs (n = 114) used were suckling lambs (BW = 11.09 kg), light lambs (BW = 22.43 kg)...

Previous research on impedance measurements for the prediction of carcass composition was predominantly carried out on animals that varied widely in body weight, breed, or sex. The high accuracy for the estimated lean or fat mass was mainly obtained by including the body weight in the regression equations. The objective of this study was the prediction of carcass composition in lambs of similar...

78 Ghezel and 76 Mehraban sheep were used to evaluate the effect of fat-tail docking on reproductive performance. Within two days after birth the tails of 32 Ghezel female lambs and 28 Mehraban female lambs were docked using a tight rubber ring. The lambs were allowed to reproduce for three lambing opportunities and their reproductive performances were evaluated. The effect of docking on the fe...

A total of 72 lambs weighing between 10.1-13.0 kg (category C of the European Union grading for light lambs) from the Bragançano, Campaniço, Merino Branco, Merino Preto e Serra da Estrela breeds were studied. These breeds represent 66.8% of the Portuguese sheep population. Evaluations were made at the same subcutaneous fat contents in the carcass (88.5 g kg(-1)). Small, significant (p < 0.05) d...

The aim of this study was to develop and evaluate models for predicting the carcass composition of lambs. Forty male lambs were slaughtered and their carcasses were cooled for 24 hours. The subcutaneous fat thickness was measured between the 12th and 13th rib and breast bone tissue thickness was taken in the middle of the second sternebrae. Left side of carcasses was dissected and the proportio...

Two / 2 East Friesian (EF), one / 4 EF, one / 8 EF, and several Dorset rams were mated to crossbred ewes from 1993 through 1996. Growth, reproduction, and lactation performance of their progeny were compared. EF-cross lambs had greater birth, weaning, and postweaning weights than Dorset-cross lambs. When lambing at one and two years of age, EF-cross ewes gave birth to and reared more lambs per ...

A quantitative trait locus (QTL) has been identified on chromosome 18 in Texel sheep (TM-QTL) that increases depth and area of the longissimus dorsi muscle. The study aimed to assess the pleiotropic QTL effects on key meat quality traits (toughness and intramuscular fat content after >or=7 days aging) of crossbred lambs carrying one copy of the TM-QTL. The results showed that male TexelxMule la...

1. Studies were conducted to measure the influence of perinatal undernutrition of twin-bearing ewes on ewe milk yields and lamb performance in early lactation. Comparative studies were conducted with lambs to measure the effects of postnatal nutrition on lamb performance and carcass composition. The major objective of this work was to determine the extent of the influence of postnatal nutrition...

Selection for lean growth through Australian Sheep Breeding Values (ASBVs) for post weaning weight (PWWT), eye muscle depth (PEMD) and c-site fat depth (PFAT) raises concerns regarding declining intramuscular fat (IMF) levels. Reducing PFAT decreased IMF by 0.84% for Terminal sired lambs. PEMD decreased IMF by 0.18% across all sire types. Female lambs had higher IMF levels and this was unexplai...