Análise de pedigree e estimativas de parâmetros genéticos para características de importância econômica em bovinos Tabapuã

A raça de bovinos de corte Tabapuã possui características desejáveis para as condições tropicais de produção como rusticidade e adaptabilidade. No entanto, é uma raça de formação recente e existem poucos estudos da estrutura populacional, variabilidade genética, endogamia e estimativas de parâmetros genéticos para características de interesse econômico. Este trabalho teve dois objetivos principais. O primeiro foi avaliar e descrever a estrutura populacional da raça Tabapuã e a relação linear de classes de coeficiente de endogamia com as médias dos valores fenotípicos de peso ao desmame ajustado para 210 dias de idade (P210), idade ao primeiro parto (IPP), intervalo de partos médio (IPM), primeiro intervalo de partos (IP1), segundo intervalo de partos (IP2) e produtividade acumulada (PAC). O segundo objetivo foi estimar parâmetros genéticos, tendências genéticas e eficiência relativa de seleção para P210, IPP, IPM, IP1 e PAC em uma população de bovinos Tabapuã. Foram utilizados registros fenotípicos de 7.340 vacas da raça Tabapuã, pertencentes ao Programa de Melhoramento Genético da Raça Tabapuã (PMGRT) mantido pela Associação Nacional de Criadores e Pesquisadores (ANCP). O arquivo de pedigree continha 15.241 animais. A análise de estrutura populacional foi realizada por meio do programa ENDOG. As estimativas dos parâmetros genéticos foram obtidas pelo método de máxima verossimilhança restrita, utilizando modelo animal multicaracterística. O teste de razão de verossimilhança foi utilizado para definir os efeitos aleatórios para análise de P210. O modelo animal de P210 incluiu os efeitos aleatórios genético aditivo materno e de ambiente permanente, além do efeito genético aditivo direto e do efeito residual e efeitos fixos. Para IPP, IPM, IP1 e PAC consideraram-se apenas o efeito aleatório genético aditivo direto, efeito aleatório residual e efeitos fixos. As tendências genéticas ...Tabapuã is a rustic beef cattle breed that is highly adapted to tropical environmental conditions. Due Tabapuã recent origin, there are only a few studies about population structure and genetic parameters. Thus, this study had two main objectives. The first was to evaluate the population structure and relationship of inbreeding coefficient and the phenotype of weaning weight adjusted at 210 days of age (W210), age at first calving (AFC), average of calving interval (ACI), first calving interval (CI1), second calving interval (CI2), and accumulated productivity (ACP). The second was to estimate genetic parameters, genetic trends and relative efficiency of selection for W210, AFC, ACI, CI1, and ACP in Tabapuã beef cattle. We used pedigree information of 15,241 animals and phenotypic information of 7,340 Tabapuã cows included in the Brazilian Tabapuã Breeding Program. Analysis of population structure was performed using ENDOG software. Estimates of genetic parameters were obtained by restricted maximum likelihood method, fitting a multiple-trait animal model. The likelihood ratio test was used to define the random effects for W210 analysis. For W210 the maternal genetic, permanent environmental, additive genetic, and residual effects were included in model; while only the additive genetic and residual effects were included for AFC, ACI, CI1, and ACP. Genetic trends were calculated from a linear regression of predicted breeding value on birth year. Average pedigree completeness was 47.99% for 6 last generations. Complete, maximum and equivalent generations were 5, 16 and 6.66, respectively. Effective number of founders and ancestors was equal to 124 and 110, respectively, and the ratio between both was 1.13. The average inbreeding coefficient was equal to 0.0072.The average inbreeding coefficient as well as the average relatedness and the percentage of number of inbred animals increased across generation. However, it was observed ..

Evaluation of Whole-Genome Sequence Imputation Strategies in Korean Hanwoo Cattle

This study evaluated the accuracy of sequence imputation in Hanwoo beef cattle using different reference panels: a large multi-breed reference with no Hanwoo (n = 6269), a much smaller Hanwoo purebred reference (n = 88), and both datasets combined (n = 6357). The target animals were 136 cattle both sequenced and genotyped with the Illumina BovineSNP50 v2 (50K). The average imputation accuracy measured by the Pearson correlation (R) was 0.695 with the multi-breed reference, 0.876 with the purebred Hanwoo, and 0.887 with the combined data; the average concordance rates (CR) were 88.16%, 94.49%, and 94.84%, respectively. The accuracy gains from adding a large multi-breed reference of 6269 samples to only 88 Hanwoo was marginal; however, the concordance rate for the heterozygotes decreased from 85% to 82%, and the concordance rate for fixed SNPs in Hanwoo also decreased from 99.98% to 98.73%. Although the multi-breed panel was large, it was not sufficiently representative of the breed for accurate imputation without the Hanwoo animals. Additionally, we evaluated the value of high-density 700K genotypes (n = 991) as an intermediary step in the imputation process. The imputation accuracy differences were negligible between a single-step imputation strategy from 50K directly to sequence and a two-step imputation approach (50K-700K-sequence). We also observed that imputed sequence data can be used as a reference panel for imputation (mean R = 0.9650, mean CR = 98.35%). Finally, we identified 31 poorly imputed genomic regions in the Hanwoo genome and demonstrated that imputation accuracies were particularly lower at the chromosomal ends

Inclusion of genomic information in estimation of genetic parameters for body weights and visual scores in Nelore cattle

The aim of this study was to evaluate genomic information inclusion in genetic parameter estimation of standardized body weight at birth and at 240, 365, and 450 days of age, and visual scores for body structure, precocity, and body muscularity, measured as yearlings in Nelore cattle. We compared genetic parameters, (co)variance components (estimated from Bayesian inference and Gibbs sampling), breeding value accuracies, genetic trends, and principal component analysis (PCA) obtained through traditional GBLUP and ssGBLUP methods. For all traits analyzed, part of the phenotypic variation was explained by the additive genetic effect, thus indicating the capacity of traits to respond to the selection process. Estimates of genetic correlation, in both methodologies, between body weights and visual scores were, in general, high and positive, showing that the selection for visual scores can lead to heavier animals. Genetic trends showed genetic progress, both when estimated breeding values and genomic estimated breeding values were used. The PCA, genetic trends, and accuracy estimates on breeding values showed that inclusion of single nucleotide polymorphism information contributed towards slightly better estimates of the genetic variability of evaluated traits. Genomic information did not bring greater gains in genetic estimates, due to redundancy of kinship information from the pedigree, which already had complete animal kinship dat

Estrus Prediction Models for Dairy Gyr Heifers

Technological devices are increasingly present in livestock activities, such as identifying the reproductive status of cows. For this, predictive models must be accurate and usable in the productive context. The aims of this study were to evaluate estrus-associated changes in reticulo-rumen temperature (RRT) and activity (ACT) in Dairy Gyr heifers provided by reticulo-rumen boluses and to test the ability of different models for estrus prediction. The RRT and ACT of 45 heifers submitted to estrus synchronization were recorded using reticulo-rumen boluses. The means of RRT and ACT at different time intervals were compared between the day before and the day of estrus manifestation. An analysis of variance of RRT and ACT was performed using mixed models. A second approach employed logistic regression, random forest, and linear discriminant analysis models using RRT, ACT, time of day, and the temperature-humidity index (THI) as predictors. There was an increase in RRT and ACT at estrus (p < 0.05) compared to the same period on the day before and on the day after estrus. The random forest model provided the best performance values with a sensitivity of 51.69% and specificity of 93.1%. The present results suggest that RRT and ACT contribute to the identification of estrus in Dairy Gyr heifers

Erythrogram, leukogram, and acute phase protein reference intervals for healthy newborn Murrah buffalo calves (Bubalus bubalis) within the first month of life

Establishing of reference intervals (RI) for hematologic variables and blood serum acute phase proteins (APP) of healthy newborn buffaloes is an important tool for monitoring alterations during infection and inflammation. Considering the scarcity of published data on newborns, the aim of the study was to establish RI for hematologic variables and APP from healthy newborn buffaloes. Blood samples from 28 healthy Murrah buffalo calves, 10–30 days old, were selected to determine RI. Fourteen hematologic and four blood APP variables were analyzed. Before collection of blood samples, calves were subjected to physical examination (rectal temperature, degree of dehydration, and fecal consistency) and only calves that were considered healthy were included in the study. The Anderson-Darling test was used to assess normal distribution of values. The Dixon test and Tukey test were used to identify outliers. RI and 90% CI were determined using standard/robust methods and Box-Cox transformation. RI for variables analyzed were the following: (1) hematologic variables: RBC 7.5–12.9 × 106/μL, HGB 10.6–19.0 g/dL, packed cell volume 33.1–54.8%, mean corpuscular volume 36.2–50.6 fL, mean corpuscular hemoglobin 12.1–17.3 pg, mean corpuscular hemoglobin concentration 28.1–42.9 g/dL, platelets 361–1081 × 103/μL, WBC 6.56–18.2 × 103/μL, lymphocytes 4.15–12.8 × 103/μL, segmented neutrophils 0.950–10.6 × 103/μL, band neutrophils 0–0.160 × 103/μL, monocytes 0–0.754 × 103/μL, eosinophils 0–0.326 × 103/μL, and basophils 0–0.149 × 103/μL and (2) APP variables: fibrinogen 2.49-9.50 g/L, haptoglobin 0.02-0.56 g/L, serum amyloid A (SAA) 3.70-97.51 μg/mL, and C-reactive protein (CRP) 0.02-2.78  μg/mL. In conclusion, hematologic and acute phase protein RI have been documented and can be used as a physiologic database to help the interpretation of laboratory results of newborn buffaloes during infection and inflammation conditions

Biodiesel Co-products Modified the Rumen Parameters of Feedlot Lambs but did not Change Methane Production In Vitro*

Background: Intensification of livestock is a strategy that increases productivity, but the diets used to increase animal production efficiency are composed mainly of corn and soybean, thereby increasing competition between animals and humans for the same food crops. This study evaluated nutrient intake, apparent digestibility of dry matter (DM) and nutrients, kinetics of gas production, and concentration of volatile fatty acids on diets with or without inclusion of biodiesel co-products formulated for feedlot lambs. So, the hypothesis is that replace of traditional ingredients by biodiesel co-products changes rumen parameters and methane emissions.Material, Methods & Results: The experiment was developed in São Paulo State University (Unesp), Jaboticabal/SP, Brazil, in Sheep Production Laboratory, which is owned to Animal Science Department. All trials developed in this study used a feedlot system, where animals were kept in individual pen. Forty Ile de France lambs male non-castrated were used in in vivo trial. To obtain rumen fluid, that was used in in vitro trial, four Santa Inês lambs with rumen cannula were used. The treatments evaluated were four diets: Control diet: roughage + concentrate; PM20: roughage + concentrate with peanut meal (PM) at 20% of DM; CG25: roughage + concentrate with crude glycerin (CG) at 25% of DM; and PMCG: roughage + concentrate with PM at 10% of DM and CG at 12.5% of DM. The roughage:concentrate ratio was 40:60 for all these diets. The parameters of the in vitro and in vivo experiments used were completely randomized with four treatments. When significant, the means between treatments were compared using Tukey test (P 0.05) among diets.Discussion: Probably the high quality of the glycerin used (83.9% glycerol, 12.01% humidity, 3.79% salts, and 0.28% organic matter, no fat, as described by the manufacturer) may explain the low EE concentration observed in the diet using only crude glycerin and the observed lack of DMI effects in all diets. About apparent digestibility, the greater values measured for crude protein can be explained by superior synchronism during fermentation of the proteins and carbohydrates in the diet. The data showed that treatment CG25 obtained higher initial gas production, followed by treatment PMCG which contained 12.5% crude glycerin. Probably these results were caused by the greater apparent digestibility of DM in treatments that included crude glycerin. Our results of volatile fatty acid concentration are different from the decrease in molar proportion of acetic acid and increase of propionic acid described by several authors, with the inclusion of glycerin in the diet. However, the absence of effect by co-product inclusion on the molar proportion of acetic, propionic, and butyric acids measured in this trial reinforce the report from other authors that affirmed the same situation. Hence, the inclusion of PM at 20% of DM and CG at 25% of DM could successfully replace the traditional diets of feedlot lambs such as soybean and corn, respectively, without damages to intake and ruminal parameters in vitro