Genetic parameters were estimated for seasonal body weight changes of cows and weaning weight of their calves in two beef herds run at pasture in a Mediterranean climate. Heritability estimates for weight changes were low. Cows predisposed to lose more weight were also likely to gain more weight, and larger cows had greater genetic potential for weight changes. Low to moderate genetic and perma...

The objective of this study was to investigate the effects of different early weaning programs on growth performance and blood parameters of dairy calves. To meet this objective, thirty Holstein calves with initial body weight of 36 ± 5 kg were randomly assigned at birth to one of the three weaning programs. Experimental groups were: 1) starter diet and whole milk from birth to 6 weeks and wean...

The genetic parameters for growth, reproductive and maternal traits in a multibreed meat sheep population were estimated by applying the Average Information Restricted Maximum Likelihood method to an animal model. Data from a flock supported by the Programa de Melhoramento Genético de Caprinos e Ovinos de Corte (GENECOC) were used. The traits studied included birth weight (BW), weaning weight (...

Direct and maternal genetic heritabilities and their correlations with body weight at 5 stages in the life span of purebred Berkshire pigs, from birth to harvest, were estimated to scrutinize body weight development with the records for 5,088 purebred Berkshire pigs in a Korean farm, using the REML based on an animal model. Body weights were measured at birth (Birth), at weaning (Weaning: mean ...

The productivity of mammalian animals is determined by the success of reproduction process to produce healthy and superior off spring with better growths and developments from birth to weaning until maturity. The fitness and health of the newborn off spring until maturity is determined by the growth and development during prenatal period with the final results of improved birth weight. The main...

To determine the relationship between within-litter birth weight variation and pre-weaning survival and weight gain, and to provide practical guidance on fostering low-birth-weight piglets, we analyzed piglet survival and weight gain in litters of piglets from 52 sows followed through eight consecutive parities. Litters with high variation in birth weight had more deaths, especially if the litt...

Effects of inbreeding and heterosis and the difference between them were estimated by comparing linecross (L), topcross (T), inbred (I) and control line (C) Hereford females for reproductive and preweaning growth traits of their progeny. Inbred females (average inbreeding coefficient = 26.5%) originated from four single-sire inbred lines. Control females (average inbreeding coefficient = 6.9%) ...

this experiment was conducted using 172 male lambs of ghezel and mehraban breeds for two periods of 60 and 80 days. two systems of fattening were studied. the first group of lambs entered feedlot boxes immediately after weaning (spring) but the second group being fed on pasture, entered the experiment approximately 4 months later (autumn). fattening periods were 60 and 80 days. the average wean...

Sheep production is affected by genetic and non-genetic factors. A knowledge of these factors is essential for efficient management and for the accurate estimation of breeding values. The objective of this study was to establish the non-genetic factors which affect birth weight and weaning weight in Dorper, Mutton Merino and indigenous Sabi sheep breeds. A total of 2,625 birth and weaning weigh...

Gilt progeny have lighter weaning weights and greater postweaning medication and mortality rates compared with the progeny of older parity sows. Because weaning weight has been positively correlated with postweaning survival, this study aimed to determine whether the provision of supplemental milk preweaning could improve weaning weight and subsequent weights as well as postweaning survival of ...