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RESUMO Objetivou-se, com este trabalho, estimar parâmetros genéticos para características do crescimento de animais da raça Nelore Mocho. Foram utilizados pesos corporais (Kg) ajustados aos 205 (P205), 365 (P365) e 550 (P550) dias. Adotou-se modelo multicaraterísticas ajustado para o efeito fixo dos grupos de contemporâneos, idade da vaca ao parto (covariável) e, para os efeitos aleatórios genético direto, genético materno, ambiente permanente materno e residual. As variâncias genéticas diretas (98,80, 276,38 e 547,52 Kg2) e maternas (61,77, 64,63 e 79,85 Kg2), elevaram-se com o avanço das idades. Observou-se redução das variâncias de ambiente permanente materno de P205 para P365 e aumento para P550. As herdabilidades diretas, e seus erros padrão, para P205, P365 e P550 foram respectivamente de 0,21 ± 0,01; 0,38 ± 0,00 e 0,39 ± 0,00. As herdabilidades maternas foram maiores no início da vida dos animais (0,13 ± 0,01, 0,08 ± 0,00 e 0,05 ± 0,00). As correlações genéticas diretas foram superiores a 0,94. As correlações fenotípicas apresentaram valores de moderados a altos (0,50 a 0,87). As correlações genéticas maternas e de ambiente permanente materno foram superiores a 0,91. Ganhos genéticos são esperados, ao se usarem as características do crescimento como critérios de seleção. A existência de variabilidade genética permite a seleção em idades menores, possibilitando a redução do intervalo de gerações e aumento do ganho genético.

The objective of this study was to establish equations for the prediction of the water intake (WI) of hair sheep. The data set used was derived from eight studies containing 185 individual observations of hair sheep:120 non-castrated males, 22 castrated males, and 43 females in a feedlot. A stepwise procedure was used, with a significance level of P < 0.05, to determine which variables would be included in the prediction model. Then, a random coefficient model was used, considering the random study effect and including the possibility of covariance between the intercept and slope. Furthermore, sex classes were considered a fixed effect and tested in the model parameters. To validate the model, the comparison between predicted and measured values was performed using the Model Evaluation System. The correlation between WI and metabolizable energy intake (MEI), body weight (BW), dry matter (DM), dry matter intake (DMI), and temperature-humidity index (THI) was significant (P<0.001), assuming values of 0.35, 0.37, 0.43, 0.54, and 0.57, respectively. The stepwise analysis indicated that DM and DMI were significant variables (P<0.001) for predicting WI in hair sheep. Sex classes did not affect (P = 0.3340) the model predicting WI in hair sheep; therefore, a single equation was generated: WI (kg/day) = 0.1282 (± 0.5861) + 2.4186 (± 0.5842) x DMI (R 2  = 0.70, MSE = 0.1631, AIC = 297.6). The validation suggests that the model accurately predicts the water intake of sheep. In conclusion, the proposed model should be used to more accurately predict WI in hair sheep and contribute significantly to improving the rational use of water.

The objective of this study was to estimate the net requirements for gain (NCu g , NFe g ; NMn g ; NZn g , NCo g , and NCr g ) and maintenance (NCu m , NFe m ; NMn m , NZn m , NCo m ; and NCr m ) in males and female hair sheep. Data from six studies, comprising 248 individual records (139 non-castrated males, 75 castrated males, and 34 females), were used to estimate net trace mineral requirements for weight gain. For maintenance requirements, 52 observations (26 intact and 26 castrated males) were analyzed. A meta-analytical approach was employed, incorporating non-linear mixed-effects models with the study treated as a random effect. Model selection was guided by the corrected Akaike information criterion (AICc) and some AICc-derived functions (Akaike difference, model probability, evidence ratio, and number of parameters of the fitted combination), which indicated that heterogeneous variance functions provided a better fit, with minimal model selection uncertainty. The final models selected effectively accounted for variability associated with sex and exhibited high confidence levels (model weights w ≥ 0.9), supporting their adequacy in describing trace mineral requirements. Sex did not affect the intercept and slope of the linear equations, and the net mineral requirements for maintenance were 34.85, 39.63, 6.11, 194, 6.06, and 11.67μg/kg of BW for Cu, Fe, Mn, Zn, Co, and Cr, respectively. The Fe requirements for gain decreased with increasing BW from 10 to 30 kg and average daily gain (ADG) of 150 g/day, ranging from 11.54 – 8.93; 10.58- 6.81; 7.16-2.91 mg for non-castrated males, castrated males, and females, respectively. The estimated dietary requirements for males with a BW of 30 kg and an average daily gain of 150 g were 69.6 mg/day for Fe;76.06 mg/day for Mn, and 2.62 mg/day for Co. Nutritional requirements for growth differ among castrated male, non-castrated male and female sheep for Fe, Mn, Zn and Cr. Thus, this study represents a significant advancement in the recommendation of nutritional requirements for trace elements in sheep breeds raised in tropical conditions.

Pollination is a key factor in global agricultural production, and there is a need to increase the number of bee species that can be bred for pollination in agriculture, such as the oil-collecting solitary bee Centris (Heterocentris) analis (Fabricius, 1804). In this study, the nesting and reproductive behavior of the bee were studied under tropical conditions, with the aim of producing information for breeding and using C. analis for crop pollination. The study was conducted from May to October 2017, using trap nests and daily observations from 5.00 a.m. to 6.00 p.m. of nest occupation and building, foraging trips in the field and interactions between individuals and kleptoparasites. The results showed that the bees easily colonize and nest in trap nests for an extended period of the year under tropical conditions, and that the use of this type of nest makes it possible to multiply populations of this species for their potential use in crop pollination. However, sources of floral oil and the availability of nesting sites have both proved to be limiting factors to population growth in this species on bee farms.

We aimed to evaluate different orders of fixed and random effects in random regression models (RRM) based on Legendre orthogonal polynomials as well as to verify the feasibility of these models to describe growth curves in Nellore cattle. The proposed RRM were also compared to multi-trait models (MTM). Variance components and genetic parameters estimates were performed via REML for all models. Twelve RRM were compared through Akaike (AIC) and Bayesian (BIC) information criteria. The model of order three for the fixed curve and four for all random effects (direct genetic, maternal genetic, permanent environment, and maternal permanent environment) fits best. Estimates of direct genetic, maternal genetic, maternal permanent environment, permanent environment, phenotypic and residual variances were similar between MTM and RRM. Heritability estimates were higher via RRM. We presented perspectives for the use of RRM for genetic evaluation of growth traits in Brazilian Nellore cattle. In general, moderate heritability estimates were obtained for the majority of studied traits when using RRM. Additionally, the precision of these estimates was higher when using RRM instead of MTM. However, concerns about the variance components estimates in advanced ages via Legendre polynomial must be taken into account in future studies.

Data from 629 meat type quails were used to study association between two different sets of traits: egg production and reproduction. Traits related to reproduction were: body weight at 42 days (W42), average egg weight (AEW), age at sexual maturity (ASM); and production traits: number of eggs produced from 42 until 182th day considering intervals of 35 days each period (P1, P2, P3 and P4). Canonical correlations were used to describe the association between these two sets of traits. The canonical coefficients indicated that egg production and reproductive traits were moderately related (0.3475). The first partial period of production (P1) and age at sexual maturity were the most relevant traits among the analyzed variables. Results show that selecting animals with lower age at sexual maturity might lead to an increase on number of eggs produced until 77 days, although it might also lead to a decrease on egg weight. Breeding programs aiming to improve quails production should consider selection strategies to decrease age at sexual maturity and then, as correlated response, increased egg production might be observed. RESUMO: Dados de 629 matrizes de codornas de corte foram utilizados para estudar a associação entre características de reprodução e produção de ovos. As características analisadas foram: peso corporal aos 42 dias (W42), peso médio de ovos (AEW) e idade à maturidade sexual (ASM), que compôs as características reprodutivas; e números de ovos produzidos a partir do 42o dia, divididos em intervalos de 35 dias cada (P1, P2, P3 e P4), que integrou o grupo de características de produção. Para análise de associação, foi utilizada a análise de correlação canônica entre os dois conjuntos de características. Os coeficientes canônicos indicaram que os conjuntos de características de produção de ovos e reprodutivas são dependentes, correlacionando-se moderadamente (0,3475). Entre as variáveis avaliadas, o primeiro período parcial de produção de ovos e a idade à maturidade sexual foram as mais importantes. Os resultados indicam que a seleção para menor idade à maturidade sexual resultaria em aumento no número de ovos produzidos até 77 dias de idade, embora essa seleção possa resultar em diminuição do peso de ovo. Conclui-se que a seleção de aves deve ser efetuada para menor maturidade sexual, pois, assim, estará selecionando também aves para maior produção de ovos.

We estimated genetic and phenotypic parameters for egg production in meat-type quails aiming to propose an optimal age for selection through partial record egg production. Data of 3,503 female quails from two strains (namely, UFV1, with 1,811 and UFV2 with 1,692 females) were used. Egg production was assessed by the number of eggs recorded after 42 days of age and each partial period consisted on 35 days of egg production forward. Covariance components were estimated by using single and bivariate animal model, comprising each partial period of egg production and full egg production period (one year of egg laying). Regarding strain UFV1, heritability estimates ranges from 0.03 to 0.16, and for strain UFV2 0.20 to 0.25. The highest genetic correlation with full egg production was with second period (0.64) for strain UFV1 and with third period (0.47) for UFV2. Therefore, animal selection based on egg production until 112 days for the strain UFV1 and 147 days for the strain UFV2 provided increased genetic gain by reducing generation interval. RESUMO: Este estudo teve como objetivo estimar os parâmetros genéticos e fenotípicos para a produção de ovos de codornas de corte e propor uma idade ideal para a seleção através da característica de produção de ovos. Os dados utilizados neste estudo vieram de 3.503 codornas de duas linhagens (1.811 fêmeas UFV1 e 1.692 fêmeas UFV2). A produção de ovos foi avaliada pelo número de ovos coletados a partir do 42o dia de vida em diante, usando modelo animal uni ou bicaracterístico, em períodos parciais de 35 dias cada e período total (um ano de postura). Para a linhagem UFV1, as estimativas de herdabilidade variaram de 0,03 a 0,16, e para a linhagem UFV2, de 0,20-0,25. A correlação genética maior foi entre o segundo período e total (0,64) para a linhagem UFV1 e 0,47 (terceiro período e total) para UFV2. Portanto, recomenda-se usar o período de produção de ovos até 112 dias para a linhagem UFV1 e o período de produção de ovos até 147 dias para a linhagem UFV2, permitindo, assim, uma redução no intervalo de geração.

The objective was to develop equations to predict carcass weight (CW), use CW to predict empty body weight (EBW); and carcass gain (CG) to predict empty body weight gain (EBWG) and retained energy (RE) in hair sheep. To generate the prediction models, a data set was composed of individual measurements from 569 sheep encompassing intact males ( n = 416), castrated males ( n = 51), and females ( n = 102). Validation analyses were performed by using the Model Evaluation System (MES). The prediction equations for CW, EBW, and EBWG were not influenced by sex class ( P > 0.05), and the following equations were generated, respectively: CW (kg) = − 0.234 (±1.1358) + 0.485 (±0.0387) × FBW; EBW (kg) = 1.367 (±0.5472) + 1.681 (±0.0210) × CW and EBWG (kg) = 0.004 (±0.0026) + 1.679 (±0.0758) × CG. There was an effect of sex class on the intercept ( P = 0.0013) of the relationship between RE and CG: RE (MJ/day) = 1.448 (±0.0657) × EBW 0.75 × CG 0.797 (±0.0399) ; RE (MJ/day) = 1.522 (±0.0699) × EBW 0.75 × CG 0.797 (±0.0399) and RE (MJ/day) = 1.827 (±0.0739) × EBW 0.75 × CG 0.797 (±0.0399) for intact males, castrated males and females, respectively. This study highlights the importance of incorporating carcass information into EBW, EBWG, and RE predictions. Replacing empty body weight gain with carcass gain might be a suitable alternative to estimate the retained energy of hair sheep. In addition, the generated equations will provide support for meat production systems in carcass weight prediction.

The aim of this research was to evaluate the dimensional reduction of additive direct genetic covariance matrices in genetic evaluations of growth traits (range 100-730 days) in Simmental cattle using principal components, as well as to estimate (co)variance components and genetic parameters. Principal component analyses were conducted for five different models-one full and four reduced-rank models. Models were compared using Akaike information (AIC) and Bayesian information (BIC) criteria. Variance components and genetic parameters were estimated by restricted maximum likelihood (REML). The AIC and BIC values were similar among models. This indicated that parsimonious models could be used in genetic evaluations in Simmental cattle. The first principal component explained more than 96% of total variance in both models. Heritability estimates were higher for advanced ages and varied from 0.05 (100 days) to 0.30 (730 days). Genetic correlation estimates were similar in both models regardless of magnitude and number of principal components. The first principal component was sufficient to explain almost all genetic variance. Furthermore, genetic parameter similarities and lower computational requirements allowed for parsimonious models in genetic evaluations of growth traits in Simmental cattle. RESUMO: Objetivou-se estudar a efetividade da redução da dimensão da matriz de covariância do efeito genético direto na avaliação genética do crescimento (pesos dos 100 aos 730 dias de idade) de bovinos Simental, por meio da análise de componentes principais, e estimar componentes de (co)variância e parâmetros genéticos. A análise de componentes principais foi realizada ajsutando-se cinco diferentes modelos: um modelo multicaracterístico padrão, de posto completo, e quatro modelos de posto reduzido. Os modelos foram comparados via informação de Akaike (AIC) e informação Bayesiana de Schwarz (BIC). Os componentes de variância e parâmetros genéticos foram obtidos via REML. Os valores de AIC e BIC para os modelos testados foram similares, indicando a possibilidade da escolha de um modelo mais parcimonioso na avaliação genética da raça Simental. O primeiro componente principal explicou mais de 96% de toda variação genética aditiva direta em ambos os modelos. Os valores de herdabilidades foram maiores em idades mais avançadas e variaram de 0,05 (peso aos 100 dias) a 0,30 (peso aos 730 dias). As estimativas de correlações genéticas foram similares em todos os modelos e apresentaram mesma magnitude e comportamento independentemente do número de componentes principais adotado. Diante dos resultados, pode-se afirmar que apenas o primeiro componente principal foi suficiente para explicar quase que na totalidade a variação genética aditiva direta existente. Além disso, a similaridade dos parâmetros genéticos estimados e a menor demanda computacional são indicativos da possibilidade da utilização de modelos mais parcimoniosos na avaliação genética de bovinos Simental.

The aim of this study was to estimate the genetic parameters for the ability of a sheep to rank among the top three in its age category (ABI3) and for its total score (TS) on the judgement championships held in different agricultural fairs in Brazil. Data files included 3180 records referring to 1896 animals for ABI3 and 4383 records referring to 2170 animals for TS. The relationship matrix was composed by 4069 animals. Variance components were estimated fitting threshold and linear animal models for ABI3 and TS, respectively, by Bayesian analysis using the Gibbs sampler. The posterior means of the heritability and repeatability were, respectively, 0.10 ± 0.07 and 0.57 ± 0.11 for ABI3 and 0.12 ± 0.04 and 0.31 ± 0.02 for TS. The low values for the heritabilities related to these traits reveal a strong influence of the environmental factors, as the differential management offered to the animals before and during the fair. The repeatability values for ABI3 suggest high correlation among the animal classifications in different fairs. However, for TS, the observed performance has moderate confidence to be repeated over time. We conclude that although reduced, there is genetic variability for the animal's performance in agricultural fairs. Nevertheless, due to the low heritability estimates, the expected response to direct selection for ABI3 and TS will be low.