Effects Of Genetic Group Research Articles

Effect of non genetic factors and genetic group on reproduction traits of Gir crossbreds maintained at organized farm

Effect of non genetic factors and genetic group on reproduction traits of Gir crossbreds maintained at organized farm

Carcass and Meat Characteristics of Cull Heifers from Different Genetic Groups Fed Diets with Different Sources of Nonprotein Nitrogen in Confinement.

The aim of this study was to evaluate the effect of genetic groups and diets with different sources of nonprotein nitrogen (NPN) on the carcass and meat characteristics of beef heifers. The meat from 40 heifers (20 ½ Angus ½ Nellore (A × N) and 20 ½ Charolais ½ Nellore (L × N)), finished in feedlots, was used. The heifers were fed diets containing different sources of NPN-(1) a diet with livestock urea and protected urea (LPU) and (2) a diet with extruded urea (EU)-in a completely randomized design with a 2 × 2 factorial arrangement. Carcass, composition and meat quality evaluations were carried out. There were no significant interactions between diet and genetic group for most of the variables evaluated (p > 0.05). The A × N heifers had higher hot carcass weights (305.73 vs. 279.80 kg), loin eye areas (80.87 vs. 75.45 cm2), subcutaneous fat thicknesses (8.69 vs. 6.35 mm) and lower shear forces (6.98 vs. 7.7 kg) compared to the C × N heifers (p < 0.05). The meat from the A × N heifers had higher proportions of saturated fatty acids (49.41 vs. 47.95%), with no effects on the proportions of monounsaturated (47.57%) and polyunsaturated (4.01%) fatty acids. The A × N heifers had better carcass and meat characteristics, while the C × N heifers had meat and fat with better fatty acid profiles.

Effect of Genetic Groups and Gender on Body Weight and Different Morphometric Traits in Poultry Birds

Background: Traits of economically importance are quantitative, complex with continuous variability in chickens whereas body morphometric parameters are variable on the basis of some factors such as age, sex, nutrition, climate and status of the birds which is very important in differentiating native from exotic as well as commercial breeds. Methods: Three genetic groups of chicken i.e., Rhode Island Red (RIR), Kadaknath and Punjab Brown were classified according to gender and genetic groups. The body weight was measured from 0 day to 26th week of age and morphometric trait from 12 to 26th week of age. The fixed effect of gender and genetic groups on different fortnightly body weights (BW) and morphometric traits were estimated. Result: Punjab Brown poultry birds had significantly higher (p≤0.01) body weight and morphometric traits viz. beak length (BKL), keel length (KL), wing length (WL) and body girth (BG) for most of the studied weeks. Male birds consistently had significantly (p≤0.01) higher body weight and important morphometric parameters viz. shank length (SL), shank width (SW), BKL, comb length (CL), KL and WL compared to females across all age groups which interprets the significance of different non-genetic factors on body weight and important morphometric parameters for further selection in different breeds of poultry birds.

Carcass characteristics and meat quality of cull cows from different genetic groups

We aimed to evaluate the quality of the carcass and meat of cull cows from different genetic groups. It was considered 48 cows being 16 of the Nellore breed (NEL), 16 ½Angus ½Nellore (ANGNEL), and 16 ½Caracu ½Nellore (CARNEL), slaughtered at the end of eight pregnancy seasons, with approximately 11 years of age. For carcass analysis, body weight at slaughter (SW), hot carcass weight (HCW), carcass yield (CY), carcass finishing (CF), fat distribution (FDIST), cold storage conformation (CSC), marbling (MAR), subcutaneous fat thickness (SFT), ribeye area (REA), internal depth (INTD), external depth (EXTD), carcass length (CL), physiological maturity (FMAT), muscle color (COLOR) and texture (TEXT). For meat analysis, samples taken from the Longissimus muscle were analyzed after zero and 14 days of maturation for exudation losses (ExuL at 0 and 14 days), cooking losses (CookL), pH (pH at 0 and 14 days), color components of meat (L*, a* and b* 0 and 14 days) and shear force (SF at 0 and 14 days), the ether extract (EE) of the samples was also evaluated according to the genetic group of the cull cows. The Means were compared according to the adjusted Tukey-Kramer test (α = 0.05). The data were evaluated for the presence of outliers, homogeneity of variance, and normality of residuals. The effects of genetic groups on the described characteristics were evaluated by restricted maximum likelihood (REML) analysis, adjusting a mixed model containing the effects of cow age, genetic group, and slaughter date. NEL and ANGNEL cows presented higher SFT results when compared to CARNEL cows. The REA, INTD, and EXTD, ANGNEL and CARNEL cows obtained greater results when compared to NEL cows group. There was no significant effect on the genetic group of cull cows for the variables CY, CF, FDIST, CSC, MARM, FMAT, COLOR and TEXT. A significant difference was observed only for the L* characteristic (0 and 14 days of maturation), in which NEL cows presented darker meat than ANGNEL, with CARNEL cows having intermediate results. The ANGNEL cull cows have higher slaughter weights, and carcass weights, and AOL and EGS with better carcass finish. Cull cows slaughtered at an advanced age, between 10 and 11 years old, have similar meat quality. We recommend the meat maturation process for 14 days to improve the tenderness of the meat from cull cows, since in this 14-day meat maturation process, calpains degrade the myofibrillar proteins at certain internal points of the molecules and improve the tenderness of the meat, regardless of the genetic group.

Environmental impact of Holstein Friesian and 3-breed crossbred dairy cows using a life cycle assessment approach applied to individual animals

This study aimed to set up a Life Cycle Assessment (LCA) approach at level of individual animals to assess the effects of a 3-breed crossbreeding program on the environmental impact of cows. It involved 564 cows, 279 purebred Holstein (HO) and 285 crossbreds (CR), originated from a 3-breed crossbreeding program based on the rotational use of Viking Red, Montebèliarde and HO sires and kept in 2 dairy herds of northern Italy (224 and 340 cows/herd, respectively). The reference unit of the LCA model was the lifetime of cows, from the birth to culling or death. Data were collected at different levels: individual animal-based data referred to the whole life (birth, calving, dry, cull or death dates, and milk production); individual test-date collection of body measures and BCS, used to predict body weight and to estimate energy requirements; common farm-based data concerning herd management (diets composition, and materials used). Data were used to compute: dry matter intake, milk and milk components production, gross income (GI) and income over feed costs (IOFC) pertaining to the lifespan of cows. An individual LCA-derived approach was set up to compute global warming potential (GWP), acidification and eutrophication potential (AP and EP, respectively), and land occupation (LO), which have been associated with different functional units (cow in her whole life or per d of life; kg of milk fat plus protein, and € of GI and of IOFC produced in the herd life). Data were analyzed using a generalized linear model including the fixed effects of genetic group (CR vs HO), farm and their interaction (genetic group x farm). Compared with HO, CR cows completed more lactations (+12%), had earlier first calving (-2 weeks), yielded more fat plus protein in milk both in the lifespan (+8%) and per d of life (+4%). Concerning the environmental impact, when compared with HO herd mates, CR cows had nominal greater emissions per cow in the whole life, similar emissions per d of life and nearly 3% lower GWP, AP and EP per kg of fat plus protein yielded in lifespan. Income over feed costs per unit of emission tended to be nearly 4% greater in CR compared with HO cows. Also the use of land tended to be lower in CR compared with HO in most indicators considered. In conclusion, LCA could be adapted to represent individual animals. Moreover, managing dairy cows according to a 3-breed rotational crossbreeding scheme may be regarded as a strategy that can contribute to mitigate the emissions and to improve the environmental impact of dairy operations.

Intake, digestibility, energy and nitrogen utilisation, and enteric methane emission in Holstein and Girolando-F1 cows during the transition period

ABSTRACT This study aimed to evaluate intake, energy and nitrogen balance as well as methane emission in Holstein and ½ Holstein ½ Gyr (Girolando-F1) cows during the transition period. Twenty-four cows (12 Holstein and 12 Girolando-F1) were used to evaluate feed intake, apparent digestibility, heat production and methane emission, carried out in two periods: from 28 to 19 days pre-calving and from 15 to 23 days post-calving. A completely randomised design was used and data were analysed by ANOVA within periods (pre- and post-calving) considering the main effect of genetic groups. Girolando-F1cows presented greater body condition score (BCS) compared with Holstein. During pre-calving, there were no differences between genetic groups, except for highest heat production per kilogram of metabolic body weight for Holstein cows. After calving, Holstein cows had greater intake of DM, nitrogen, NDF per kg of BW and produced more heat per kg of metabolic body weight. Holstein cows yielded more milk and fat-corrected milk (FCM4%) compared with Girolando-F1 cows. Holstein cows presented higher methane emission per unit of BW and of metabolic weight. Emissions of enteric methane per kilogram of milk and per kilogram of FCM4% tended to be lower for Holstein compared with Girolando-F1 cows. Nitrogen and energy retention were similar for both Holstein and Girolando-F1 at pre- and post-calving. Despite differences in BCS, DMI, and milk yield, Girolando-F1 and Holstein cows present overall similar energy efficiency, albeit Holstein cows tended to present less methane emission per kg of eligible product (milk).

Performance Evaluation of Khari and Boer Crossbred Goats in Mid Hills Under Optimum Management Regime.

Goats are recognized as a vital and versatile livestock commodity with significant importance in rural farmers’ communities of developing countries, including Nepal. Growth, reproductive and litter performances are considered as the major economic traits of goats. This study was designed to compare the growth, reproduction and litter traits of goat kids and does at mid hill region for different non-genetic factors such as genetic groups (Khari, Boer 75% and 50%), parity (early, mid and late), season of conception and kidding (summer, autumn, winter, spring), sex (male and female) and type of birth (single, twins and triplet) under optimum management regime. Data for the four-year study period (2017 to 2021) on production performance were entered into MS-Excel sheet from the data record book of the National Goat Research Program, Bandipur and analyzed by using Mixed Model Least-square and Maximum Likelihood Computer Program PC-2 statistical package. The means were compared using Duncans' Multiple Range Test (DMRT). Results revealed that the effect of genetic group, parity, type of birth and sex were significant (p&lt;0.05) with respect to growth at different stages along with genetic group and parity that were significant with major non-genetic factors affecting reproduction and litter traits. Better reproduction parameters were recorded for the Khari goat breed than Boer crossbred. Similarly, litter traits at both birth and weaning were found better in later parities with better performance in Khari. Males were born heavier and consistent throughout the study period up to eighteen months. Hence, based on the findings of this study, it can be concluded that Khari goat breed has high potential for its reproduction and litter traits with a massive scope of improvement through selection within the population. Likewise, it is also important to consider the growth of inferior Khari goats can also be genetically improved through upgrading up to 75% blood level using an appropriate breed, such as Boer.

Dynamics ofthe rice yellow mottle disease inwestern Burkina Faso: Epidemic monitoring, spatio-temporal variation ofviral diversity, andpathogenicity ina disease hotspot.

The rice yellow mottle virus (RYMV) is a model in plant virus molecular epidemiology, with the reconstruction of historical introduction routes at the scale of the African continent. However, information on patterns of viral prevalence and viral diversity over multiple years at a local scale remains scarce, in spite of potential implications for crop protection. Here, we describe a 5-year (2015-9) monitoring of RYMV prevalence in six sites from western Burkina Faso (geographic areas of Bama, Banzon, and Karfiguela). It confirmed one irrigated site as a disease hotspot and also found one rainfed lowland (RL) site with occasional high prevalence levels. Within the studied fields, a pattern of disease aggregation was evidenced at a 5-m distance, as expected for a mechanically transmitted virus. Next, we monitored RYMV genetic diversity in the irrigated disease hotspot site, revealing a high viral diversity, with the current coexistence of various distinct genetic groups at the site scale (ca. 520 ha) and also within various specific fields (25 m side). One genetic lineage, named S1bzn, is the most recently emerged group and increased in frequency over the studied period (from 20 per cent or less in 2015-6 to more than 65 per cent in 2019). Its genome results from a recombination between two other lineages (S1wa and S1ca). Finally, experimental work revealed that three rice varieties commonly cultivated in Burkina Faso were not different in terms of resistance level, and we also found no significant effect of RYMV genetic groups on symptom expression and viral load. We found, however, that infection outcome depended on the specific RYMV isolate, with two isolates from the lineage S1bzn accumulating at the highest level at early infections. Overall, this study documents a case of high viral prevalence, high viral diversity, and co-occurrence of divergent genetic lineages at a small geographic scale. A recently emerged lineage, which comprises viral isolates inducing severe symptoms and high accumulation under controlled conditions, could be recently rising through natural selection. Following up the monitoring of RYMV diversity is required to confirm this trend and further understand the factors driving the local maintenance of viral diversity.

Genetic group and swim-up processing affect SYBR Green real-time PCR-based porcine semen sex ratio in Landrace and its crossbred boars.

Determination of factors affecting sex ratio is important while considering application of sex ratio enrichment approach. Present study aimed to design a SYBR Green qPCR-based method for measurement of primary sex ratio and to evaluate different factors (genetic group, sire, spermiogenic cycle and processing layer) affecting boar sperm sex ratio. The qPCR was based on relative copy number analysis of sex chromosome-specific single copy gene fragments with an autosomal gene as reference and was evaluated using DNA dilution series from pigs with numerically normal karyotype. The sex ratio was estimated from genomic DNA samples isolated from boar semen collected from different genetic groups at different time points and different processing layers. The X chromosome frequencies of semen samples revealed significant effect of genetic group. However, significant variation was observed neither within same genetic group nor between ejaculates of different spermatogenic cycles. Among the processing techniques studied, swim-up technique produced a significant X sperm enrichment in comparison to control whereas, Percoll density gradient failed to show any significant difference among layers. The lower layer in swim-up technique was found to contain higher proportion of X sperms. The designed qPCR is found to be an easy, less time-consuming method and does not require high end laboratory facilities or the specialized expertise. The lower layer of swim-up processing has a scope for X sperm enrichment in boar semen with proper validation.

Differences in body temperature regulation during heat stress and seasonal depression in milk yield between Holstein, Brown Swiss, and crossbred cows

It is not clear whether cattle that are genetically superior in regulation of body temperature during heat stress are also better able to sustain milk production during hot conditions. Objectives were to evaluate differences in body temperature regulation during heat stress between Holstein, Brown Swiss, and crossbred cows under semi-tropical conditions and test whether the seasonal depression in milk yield was greater for genetic groups less able to regulate body temperature. For the first objective, conducted during heat stress, vaginal temperature was measured at 15-min intervals for 5 d in 133 pregnant lactating cows. Vaginal temperatures were affected by time and interaction between genetic group and time. Vaginal temperatures were higher for Holsteins for most times of the day. Moreover, the maximum daily vaginal temperature was higher for Holstein (39.8 ± 0.1°C) than for Brown Swiss (39.3 ± 0.2°C) or crossbreds (39.2 ± 0.1°C). For the second objective, 6,179 lactation records from 2,976 cows were analyzed to determine effects of genetic group and season of calving (cool season = Oct to March; warm season = April to Sept) on 305-d milk yield. Milk yield was affected by genetic group and season but not by the interaction of genetic group and season. The difference in average 305-d milk yield between cows calving in cool versus hot weather was 310 kg (4% decrease) for Holstein, 480 kg (7% decrease) for Brown Swiss, and 420 kg (6% decrease) for crossbreds. In conclusion, Brown Swiss and crossbreds regulated body temperature during heat stress better than Holsteins but these breeds were not more resistant to heat stress with respect to milk yield. Thus, genetic differences in thermotolerance are likely to exist that are independent of regulation of body temperature.

Depicting latent variables considering different pig genetics and nutritional plans in crossbred pigs

We aimed to reduce the dimensionality of quantitative traits in pigs applying factor analysis. Quantitative variables were collected, and the factor analysis extracted five factors with biological meaning related to performance, carcass quality, carcass yield, meat quality, and initial pH. These factors were posteriorly used as dependent variable to evaluate the effects of genetic groups (Piau, Duroc, and Pietrain crossbreds), nutritional plans (low, medium and high lysine levels) and sex. An interaction effect between genetic group and sex was [...]

Meta-analysis and meta-regression of core body temperature in taurine and zebuine cattle under different environmental conditions

Heat stress affects livestock productivity and is often determined by an increase in the core body temperature (CBT). To evaluate the latter, both vaginal and rectal temperatures can be used. The aims of this study were (1) to perform a meta-analysis in order to evaluate the impact of heat stress in comparison to thermoneutral conditions on CBT in Bos taurus and Bos taurus indicus cattle, and (2) to evaluate the effects of genetic group, sex, productive purpose, climate zone, and temperature-humidity index (THI class) heat stress on the vaginal and rectal temperatures of cattle. Eighty-nine studies were included in this meta-analysis. Systematic review and meta-analysis were performed following the PRISMA guidelines. The standardized mean difference (SMD) in CBT between the heat stress (HS) and thermoneutral (TN) environments was used as a measure of effect size, considering a 95% confidence interval (CI). Cochran's Q test and I² statistic indicated high variability among studies; thus, a random effects model was used. Subgroup and meta-regression analysis were performed to investigate the source of heterogeneity. Genetic group, sex, productive purpose, climate zone, and THI class were included as covariates. The SMD in CBT between the HS and TN environments was 7.45 °C (95%CI: 5.89;9.02 °C, P = 0.0001), indicating a physiological response to the heat stress condition. The SMD in CBT was 3.92 °C higher in Bos taurus than Bos taurus indicus animals (P < 0.05). Animals in climate zone D (warm temperate zone) showed a lower SMD in CBT than those in climate zone B (arid zone) (SMD = 4.04 ºC vs 12.38 ºC). The THI class affected the SMD in CBT (P < 0.05). The genetic group, climate zone, THI class and interaction between genetic group and climate zone explained 29.89% of the heterogeneity observed among studies. In conclusion, heat stress exposure affects the vaginal and rectal temperatures of cattle. The CBT measured by rectal and vaginal temperatures can be used to detect heat stress-induced changes in CBT. Bos taurus and Bos taurus indicus animals seem to respond differently to heat stress in terms of CBT.

Performance and enteric methane emission of growing beef bulls from different genetic groups subjected to two supplementation strategies grazing tropical grass in the rainy season

Improving livestock production through nutrition and breeding can increase efficiency and has the potential to mitigate methane (CH4) emissions. Additionally, supplementing beef cattle in the rainy season balances the dietary protein:energy (P:E) ratio, which can increase animal performance and reduce energy losses from CH4 production. Therefore, the objective of this study was to evaluate the effect of supplementation strategy (SS) and genetic group (GG) on the intake, digestibility, performance, and enteric CH4 emissions of growing beef bulls grazing tropical grass during the rainy season. One hundred sixty-two growing beef bulls averaging (mean ± SD) 10 ± 2 months old and 262 ± 31 kg of initial body weight (BW) were distributed, according to their BW, in a randomized complete block design in a 2 × 3 factorial arrangement. Factors included (1) two SSs (mineral supplementation at 0.3 g/kg of BW per day and a corn-based supplementation at 3 g/kg of BW per day) and (2) three GGs (Nellore [NN], ½Senepol½Nellore [SN], and ½Angus½Nellore [AN]). Animals were allocated in 12 paddocks composed of Urochloa brizantha (A. Rich.) Stapf. cv. Xaraés for 99 days during the rainy season. Regardless of the GG, the intakes of total DM, supplement DM, OM, CP, aNDFom, EE, and NFC were increased in animals supplemented with a corn-based supplement. The SN bulls had a greater digestibility of DM, OM, and CP, and animals supplemented with a corn-based supplement had greater CP and EE digestibility. There was an interaction between GG and SS for NFC digestibility, which was decreased in AN animals fed a corn-based supplement. However, the corn-based supplementation improved the animal’s performance and carcass characteristics as demonstrated by the increase of final BW (kg), ADG (kg), REA (cm2), and FT (mm). Moreover, NN animals fed a corn-based supplement showed an increase in ADG (kg). An interaction between SS and GG was observed for GPH (kg/ha) and CaG (kg), with the greatest values observed in NN and SN animals supplemented with a corn-based supplement. Enteric CH4 emissions (g/d, g/kg of DMI, and g/kg of dOM) were lower in animals fed a corn-based supplement. A decrease in CH4 emissions (g/d) was observed in SN compared to NN animals. In addition, there was an interaction between SS and GG for CH4 emissions (g/kg of CaG), with the lowest values for NN and SN animals supplemented with a corn-based supplement. Taken together, our results demonstrate that corn-based supplementation is an effective nutritional strategy for use in the rainy season, especially for NN and SN genetic groups, to improve animal’s performance and carcass characteristics and to decrease enteric CH4 emissions, per unit of product, of growing beef bulls grazing tropical grass.

​Effect of Non-genetic Factors on Reproductive Parameters and Greasy Fleece Yield in Kashmir Merino Sheep

Background: A study was undertaken to estimate gestation length, birth weight, dam weight and greasy fleece yield in Kashmir Merino sheep and factors influencing these traits at Sheep Breeding Farm, Kralpathri in 2020-21. Methods: The traits considered in the study were overall all body weight of dams at tupping (DWT), average wool yield of dams (AWY), gestation period (GP) and birth weight (BW). The averages of 39.00±0.27 (kg), 2.38±0.02 (kg), 150.17±0.17 (days) and 3.87±0.04 (kg) for DWT, AWY, GP and BW with coefficient of variation 12.83%, 12.75,1.65 and 17.70, respectively were observed in the present study. The data was analyzed by Harvey, 1990. Result: Highest and lowest CV (%) was observed for BW and GP, respectively. Overall estimates of 37.43±0.41 (kg) and 2.21±0.02 (kg), 150.59±0.56 and 2.84±0.11 for DWT, AWY, GP and BW, respectively was observed in the present study. Effect of age of dam was significant (p less than 0.05) on DWT and AWY whereas effect of lamb weight at birth was significant on GP. The effect of genetic group of sire, dam weight, parity of dam, body weight of dam at tupping, sex and birth type of lamb had significant (p less than 0.05) effect on BW. Heaiver lambs were born to heavier dams. Therefore, increasing selection pressure at tupping for dam weight will result in improvement of birth weight and hence overall production performance of Kashmir Merino sheep.

Gene-Environment Interactions in Face Categorization: Oxytocin Receptor Genotype x Childcare Experience Shortens Reaction Time.

Human faces capture attention, provide information about group belonging, and elicit automatic prepared responses. Early experiences with other-race faces play a critical role in acquiring face expertise, but the exact mechanism through which early experience exerts its influence is still to be elucidated. Genetic factors and a multi-ethnic context are likely involved, but their specific influences have not been explored. This study investigated how oxytocin receptor gene (OXTR) genotypes and childcare experience interacted to regulate face categorization in adults. Information about single nucleotide polymorphisms of OXTR (rs53576) and experiences with own- and other-race child caregivers was collected from 89 Singaporean adults, who completed a visual categorization task with own- versus other-race faces. Participants were grouped into A/A homozygotes and G carriers and assigned a score to account for their type of child caregiver experience. A multivariate linear regression model was used to estimate the effect of genetic group, child caregiver experience, and their interaction on categorization reaction time. A significant interaction of genetic group and child caregiver experience (t = 2.48, p = 0.015), as well as main effects of both genetic group (t = −2.17, p = 0.033) and child caregiver experience (t = −4.29, p < 0.001) emerged. Post-hoc analysis revealed that the correlation between categorization reaction time and child caregiver experience was significantly different between the two genetic groups. A significant gene x environment interaction on face categorization appears to represent an indirect pathway through which genes and experiences interact to shape mature social sensitivity to faces in human adults.

Model definition for genetic evaluation of purebred and crossbred lambs including heterosis.

Crossbreeding is a common practice among commercial sheep producers to improve animal performance. However, genetic evaluation of U.S. sheep is performed within breed type (terminal sire, semi-prolific, and western range). While incorporating crossbred records may improve assessment of purebreds, it requires accounting for heterotic and breed effects in the evaluation. The objectives of this study were to: 1) describe the development of a paternal composite (PC) line, 2) determine the effect of direct and maternal heterosis on growth traits of crossbred lambs, 3) estimate (co)variance components for direct and maternal additive, and uncorrelated maternal environmental, effects, and 4) provide an interpretation of the estimates of random effects of genetic groups, and to use those solutions to compare the genetic merit of founding breed subpopulations. Data included purebred and crossbred records on birth weight (BN; n = 14,536), pre-weaning weight measured at 39 or 84 d (WN; n = 9,362) depending on year, weaning weight measured at 123 d (WW; n = 9,297), and post-weaning weight measured at 252 d (PW; n = 1,614). Mean (SD) body weights were 5.3 (1.1), 16.8 (3.9) and 28.0 (7.6), 39.1 (7.2), and 54.2 (8.7) kg for BN, WN (at the two ages), WW, and PW, respectively. In designed experiments, the Siremax, Suffolk, Texel, Polypay, Columbia, Rambouillet, and Targhee breeds were compared within the same environment. Estimates of heterotic effects and covariance components were obtained using a multiple trait animal model. Genetic effects based on founders' breeds were significant and included in the model. Percent estimates of direct heterosis were 2.89 ± 0.61, 2.60 ± 0.65, 4.24 ± 0.56, and 6.09 ± 0.86, and estimates of maternal heterosis were 1.92 ± 0.87, 4.64 ± 0.80, 3.95 ± 0.66, and 4.04 ± 0.91, for BN, WN, WW, and PW, respectively. Correspondingly, direct heritability estimates were 0.17 ± 0.02, 0.13 ± 0.02, 0.17 ± 0.02, and 0.46 ± 0.04 for BN, WN, WW, and PW. Additive maternal effects accounted for trivial variation in PW. For BN, WN, and WW, respectively, maternal heritability estimates were 0.16 ± 0.02, 0.10 ± 0.02, and 0.07 ± 0.01. Uncorrelated maternal environmental effects accounted for little variation in any trait. Direct and maternal heterosis had considerable impact on growth traits, emphasizing the value of crossbreeding and the need to account for heterosis, in addition to breed effects, if crossbred lamb information is included in genetic evaluation.

Effect of breed and some non-genetic factors on growth performance of sheep under temperate conditions of Kashmir

The data pertaining to 4849 birth records spanning over a period of 21 years (1997–2017) of different genetic groups were collected from Mountain Research Centre for sheep and goat Station (MRCSG), Shere Kashmir University of Agricultural Science and Technology, Kashmir (SKUAST-K), Shuhama, Kashmir to investigate the effects of genetic group and non-genetic factors on growth performance of Bakarwal, Corriedale, Hampshire x Corrriedale Cross, Hampshire, Non-descript x Corriedale Cross, Non-descript x Polled Dorset Cross, Polled Dorset x Corriedale, Polled Dorset and South down sheep genetic groups. The non-genetic factors considered were period of birth sex of lamb whereas the growth profile traits considered were birth weight (BW), weaning weight (W3), six months body weight (W6), yearling body weight (W12), average daily gain from birth to weaning (ADG1), metabolic mass at weaning (W30.75), Kleiber ratio from birth to weaning (KR1), average daily gain from weaning to yearling age (ADG2), metabolic mass at yearling age (W120.75) and Kleiber ratio from weaning to yearling age (KR2). The overall least-squares means for BW, W3, W6, W12, ADG1, W30.75, KR1, ADG2, W120.75 and KR2 were 3.47 ± 0.04 kg, 13.30 ± 0.15 kg, 18.13 ± 0.19 kg, 23.79 ± 0.25 kg, 107.58 ± 1.54 g/day, 6.93 ± 0.06 kg, 15.20 ± 0.12, 37.21 ± 0.86, 10.81 ± 0.09 and 3.37 ± 0.06, respectively. The effect of genetic group and period was highly significant (p < 0.01) on all the traits under study whereas effect of sex was significant (p < 0.05) on BW, W3, W6, W12, ADG-1, ADG-2, W30.75 and W120.75 with sexual dimorphism of 1.03, 1.08, 1.09, 1.06, 1.03, 1.05, 1.07, 1.09, 1.05 and 1.04 for BW, W3, ADG1, W30.75, KR1, W6, W12, ADG2, W120.75 and KR2, respectively. The effect of interaction of genetic group and period of birth was highly significant (p > 0.01) whereas the effect of interaction of sex and period of birth was significant (p > 0.05) on all the traits under study. The effect of interaction of genetic group and sex was significant on BW, W3, ADG1 and W30.75 only. Pre-weaning average daily gains (ADG1) and Kleiber ratio (KR1) were higher than post-weaning average daily gains (ADG2) and Kleiber ratio (KR2), respectively in all genetic groups. Whereas the metabolic mass at weaning (W30.75) was lower than metabolic mass at yearling age (W120.75) in all genetic groups. The non-genetic factors of sex and period were observed to be important sources variation in the growth performance of sheep. The study concludes that Hampshire x Corrriedale cross outperformed other genetic groups with respect to ADG2 and W12. Further, environment plays significant role in performance of genotype. Hence, Hampshire x Corrriedale cross should intersemated to produce and evaluate F2 generation for post-weaning growth rate.

Genetic evaluation of growth performance of Rambouillet sheep in Jammu and Kashmir, India

The present study was conducted to genetically evaluate the growth performance in Rambouillet sheep. For this, data of 7,158 lambs born to 181 sires over a 16 year period from 2000 to 2015 were collected from Government Sheep Breeding Farm, Reasi, India. Random effect of sire as well as fixed effects of sex, genetic group, year, parity and birth type on the performance of this breed were evaluated. Ten traits were taken into consideration, viz. birth weight (BW), weaning-weight (WW), 6 months body weight (SMW), 12 month weight (YBW), average daily gain (birth to weaning) (ADG-1), metabolic mass at weaning age (WW0.75), Kleiber ratio (birth to weaning) (KR-1), average daily gain (weaning to yearling age) (ADG-2), and metabolic mass at 12 months (YBW0.75) and Kleiber ratio (weaning to 12 months) (KR-2). The overall least-squares means for BW, WW, SMW, YBW, ADG-1, WW0.75, KR-1, KR-2, ADG-2, and YBW0.75 were 3.16±0.05 kg, 13.79±0.16 kg, 18.81±0.22 kg, 28.00±0.26 kg, 116.93±1.72 g/day, 7.13±0.06 kg, 16.22±0.11, 4.38±0.10, 53.95±1.36 g/day, and 12.14±0.08 kg respectively. The sire and year effects of birth were significant. The genetic group was a non-significant source of variation for all traits under study. Sex effect was significant on most traits under study. Heritability ranged from low to moderate. Genetic and phenotypic correlations also ranged from low to very high. Genetic, phenotypic and environmental trends for BW, WW and WW0.75, genetic trends for BW, WW, SMW and WW0.75 and environmental trends for YBW, YBW0.75 and KR-2 were negative. Our results indicate that most of the variation may be attributed to nonadditive genetic effects and may also be influenced by the environment.

Morphometric measurements of calves of beef cattle from different genetic groups up to one year of age

Heterosis plays an important role on yield and profitability of beef production systems. This study evaluates the morphometrics of purebred Nellore (N) and Charolais (C) animals and of the second (G2) and third (G3) generations of their alternating crosses, regarding the effects of genetic group and heterosis from birth to 365 days of age. The experiment comprised 159 calves (C = 29, N = 22, G2 - 3/4C 1/4N = 21, 3/4N 1/4C = 9, G3-5/8C 3/8N = 44 and 5/8N 3/8C = 34). The foreshank girth (FG), thoracic girth (TG), body length (BL), and hip height (HH) were measured after birth, and at 63, 210, and 365 days of age, and the total increases were calculated. The Charolais animals had greater FG, TG, and BL values than Nellore, while the latter had greater HH. For the offspring generations, the predominance of Charolais genes in the genotypes resulted in greater measurements for FG and TG in G2, whereas the predominance of Nellore genes resulted in higher HH values in both generations. The crossbred animals had greater values for all measurements than the purebreds, with more significant differences in FG, TG, and BL compared to Nellore purebreds and in HH compared to Charolais. Charolais animals show higher values for muscularity; while, Nellore animals are taller. Crossbred animals show greater development compared to purebreds, indicating a significant effect of heterosis.

Sire evaluation and effect of various factors on growth performance in males of Tharparkar and Karan fries cattle

The current study was undertaken with the objective of sire evaluation as well as studying the effect of genetic and non-genetic factors on growth performance in males of Tharparkar and Karan Fries Cattle. Data on body weights of Tharparkar and Karan Fries males born during the period 1994-2012 at ICAR-NDRI, Karnal, were utilized. The overall least squares means of birth weight and weights at one-month interval up to 12 months of age were 26.92±0.24, 35.55±0.22, 45.04±0.28, 57.56±0.40, 70.02±0.51, 82.62±0.66, 95.18±0.80, 105.11±1.55, 108.19±1.15, 114.20±1.15, 120.11±1.09, 130.35±1.11 and 136.91±4.13 kg respectively, in KF males. In TP males, least square means for birth and one-month were 21.34±0.77 and 25.63±0.67 kg, respectively. Effect of month and period of birth was highly significant on all traits except 1 month and 12-months for the former effect. The effects of genetic group and parity were mostly significant on body weights in KF males. Regression on birth weight was highly significant for all the weight traits. Effect of sire and birth-month was highly significant on all traits except one-month weight in KF. In Tharparkar, effect of season was highly significant on birth weight. Growth curves were linear, and deviations of average body weekly weight showed more divergence with increasing age. Growth rates from birth to three-months age in KF and TP males were 320 g/day and 226 g/day. Effect of non-genetic factors indicated the need of further improvement in feeding and management practices for augmenting growth, i.e. body weights especially in calves born to primiparous dams.