Optimal model for weaning-weight of Bunaji Bulls at NAPRI Farm, Shika, Nigeria

Empirical models have over the years been commonly established by animal research centers for the study of weight-age profiles in order to understand the metabolic processes of growth. They provide efficient parameter estimates for mature weight and rate of maturing, but were found to consistently either over-or-under estimate the mature weight. estimate the mature weight. They also perform poorly in predicting weight in early life or beyond the range of input data. At the National Animal Production Research Institute (NAPRI) farm, Shika, Brody was established as the model that provides efficient parameter estimates of weight-age profiles for Bunaji bulls. However, a major drawback of the model is its consistent underestimation of weight prior to six months of age, leading to poor prediction of weaning weight. To address this shortcoming, we propose in this article a joint mean-covariance model that provide optimal parameter estimates for the weaning weight of Bunaji bulls

The Effect of Age of Dam and Birth Rank on the Reproductive Performance of Ewes as One- and Two-Year-Olds

Currently, 30–43% of New Zealand sheep farmers breed their ewe lambs, but few retain the offspring as replacements for their flock. No difference in lamb production as a yearling among singletons and twins born to ewe lambs and twins born to mature ewes has been reported, provided the ewe lambs had reached the 60–65% of their likely mature weight prior to breeding at seven to eight months of age. The aim of this experiment was to determine the lamb production from singletons and twins born to ewe lambs and twins born to mature ewes during their first two years of lambing. The experiment included 8-month-old ewes born as twins to mature ewes (M2, n = 135), singletons born to ewe lambs (L1, n = 135), and twins born to ewe lambs (L2, n = 88), bred during the same period to the same rams, over two years. The efficiency of lamb production (total litter weight at weaning divided by the pre-breeding weight of the ewe, for all ewes presented for breeding) after two years of production was not significantly different (p > 0.05) among the groups (0.40 ± 0.02, 0.39 ± 0.02, and 0.39 ± 0.03, for M2, L1, and L2, respectively).

CHARACTERISATION OF WHITE FULANI AND SOKOTO GUDALICATTLE BREEDS IN BAUCHI STATE NIGERIA

The study was conducted in Bauchi state between January, and July, 1997 to characterize White fulani and Sokoto Gudali cattle breeds. Thirty animals of both sexes from each breed were randomly seleted from fifteen farms/herds. Obervations were carried out on both quantitative and qualititative characters. sokoto Gudali was significantly (P<0.05) higher in five qantitative traits, white Fulani was significantly (P<0.05)higher in one quantitative traits only. Sokoto Gudali was higher in lactation yield (3211) than White Fulani (1951L). Tail length was 128.5cm for Sokoto Guadli males and 114.8cm for White Fulani males. Sokoto Gudali femals had tail length of 127.2cm vs 116.3cm for White Fulani femals. Scrotal circumference was 210.8cm in Sokoto Gudali females vs 198.3cm in White Fulani females. Mature weight in Sokoto Gudali femals was 758.5kg vs 634.6kg in White Fulani femals. the White Fulani breed was significantly (P<0.05)higher in number of days dry, 129.9 days vs 104.8 days for Sokoto Gudali breed. The descriptive (quantitative) parameters also showed marked differences between breeds.

Association of TMEM8B and SPAG8 with Mature Weight in Sheep

Signature of selection studies have identified many genomic regions with known functional importance and some without verified functional roles. Multiple studies have identified Transmembrane protein 8B (TMEM8B)rs426272889 as having been recently under extreme selection pressure in domesticated sheep, but no study has provided sheep phenotypic data clarifying a reason for extreme selection. We tested rs426272889 for production trait association in 770 U.S. Rambouillet, Targhee, Polypay, and Suffolk sheep. TMEM8Brs426272889 was associated with mature weight at 3 and 4 years (p < 0.05). This suggested selection for sheep growth and body size might explain the historical extreme selection pressure in this genomic region. We also tested Sperm-associated antigen 8 (SPAG8) rs160159557 encoding a G493C substitution. While this variant was associated with mature weights at ages 3 and 4, it was not as strongly associated as TMEM8Brs426272889. Transmembrane protein 8B has little functional information except as an inhibitor of cancer cell proliferation. To our knowledge, this is the first study linking TMEM8B to whole organism growth and body size under standard conditions. Additional work will be necessary to identify the underlying functional variant(s). Once identified, such variants could be used to improve sheep production through selective breeding.

Additive and non-additive effects for mature weight in beef cattle

Selection has emphasized animal growth, leading to an increase in their mature size affecting in some cases the pregnancy of the cows and the efficiency of the systems. Usually, crossbreeding improve productivity because of the genetic effects that the cows exploit, but the impact on mature weight (MW) has not been studied. The present study aimed at estimating MW and genetic parameters associated with the MW in crosses between two British breeds: Hereford (H/H) and Angus (A/A), a Continental: Salers (S/S), and a Zebu: Nelore (N/N). MW was analyzed at 4; 4.5; 5; 5.5 and 6 years of age using a repeated-measure sire model. For parameters estimation, an additive – dominant model was used including the fixed effects of breed group, contemporary group, and age as covariate linear and quadratic, with the linear regression fitted by breed group. Permanent environmental and sire were included as random effects. According to the results, it is expected to observe heterosis between H/H and N/N, however, the structure of the data may not be enough for estimate accurately the genetic parameters in this trait. The A/H, N/H, S/H, S/SH and H/NH cows were heavier than the H/H cows. All the breed groups continue gaining weight until six years of age. The results revealed that British crossbred animals are heavier than H/H at the first crossing but not in the following. Crossbred cows with proportions of 0.5 and greater for the Continental breed are heavier than H/H cows. Crosses between British and Zebu cows have higher mature weight than H/H at the first crossing and in backcrosses toward the British in all ages.

Genetic parameters for weights from birth to 10 years of age in different beef cow breeds

Context Most Brazilian beef breeding programs perform selection for young bodyweight, which will inevitably increase mature weight due to the genetic correlation among weights at different ages. Aims The objective of the present study was to estimate genetic parameters for bodyweight from birth to maturity in Gir, Guzerat, Nelore and Caracu cows born between 1981 and 2014 at Centro APTA Bovinos de Corte, Instituto de Zootecnia, Sertãozinho, São Paulo, Brazil. Methods The model included the fixed effects of contemporary group (herd and year of birth), month of birth and previous reproductive status (calved = 1, or not calved = 0), the linear and quadratic effects of animal and cow age as covariates, and direct additive genetic, maternal genetic and maternal permanent environmental effects as random effects. The genetic parameters were estimated by univariate analysis of weights adjusted at birth, and at 120, 210, 378, 450 and 550 days of age, and annually from 2 to 10 years. In addition, multivariate analysis was performed considering weights at birth, and at 210 and 550 days, and at 5 years of age for all breeds. Key results For the different breeds, the heritability estimates ranged from 0.28 to 0.49 for birthweight, from 0.11 to 0.31 for weaning weight, from 0.25 to 0.43 for yearling weight, and from 0.25 to 0.69 for weights from 2 to 10 years of age. The genetic correlations were high and positive, indicating that selection at any age will affect weights at the other ages. Conclusions The results suggest the possibility of genetic progress for weights at different ages and the use of the young weights to monitor the mature weight of the animals. Implications As the trait most strongly correlated with mature weight was yearling weight, already used as the selection criteria for females in the breeding program of the Instituto de Zootecnia, selection indexes should be derived to keep the mature cow weight constant, since heavier cows could be undesirable for pasture-based Brazilian production systems.

Características da carcaça e composição tecidual da carne cordeiros confinados com o uso de dietas de alto grão

This study aimed to evaluate the effect of using different high-grain diets on the carcass characteristics and tissue composition of the meat of feedlot-finished lambs. Thirty-two male castrated Texel lambs born from single births and weaned at approximately 50 days of age were allotted to treatments that consisted of different unprocessed grains, as follows: corn grain, white oat grain, black oat grain, or grain of rice in the husk. The animals were slaughtered upon reaching the pre-established slaughter weight of 32 kg, which corresponds to 60% of the mature weight of their mothers. Lambs fed the high-corn grain diet had higher weights and yields of hot and cold carcass and larger loin-eye areas than those finished in the feedlot receiving high-grain diets based on white oat, black oat, or rice in the husk. Additionally, they had a higher degree of fatness and a thicker subcutaneous fat layer at slaughter, which lead to decreased cooler shrink loss. The neck, shoulder, ribs, and leg cuts were heavier in lambs fed the high-corn grain diet. By contrast, these lambs had a lower proportion of leg, more rib, and higher meat fat content, which may be undesirable for the consumer market. The use of high-corn grain diets, in comparison with high-grain diets based on black oat, white oat, and rice in the husk, may be recommended for finishing lambs in the feedlot when they are slaughtered at similar weights.