Cattle temperament is a complex trait, and molecular studies aimed at defining this trait are scarce. We used an interaction networks approach to identify new genes (interacting genes) and to estimate their effects and those of 19 dopamine- and serotonin-related genes on the temperament traits of Charolais cattle. The genes proopiomelanocortin (POMC), neuropeptide Y (NPY), solute carrier family 18, member 2 (SLC18A2) and FBJ murine osteosarcoma viral oncogene homologue (FOSFBJ) were identified as new candidates. Their potential to be associated with temperament was estimated according to their reported biological activities, which included interactions with neural activity, receptor function, targeting or synthesis of neurotransmitters and association with behaviour. Pen score (PS) and exit velocity (EV) measures were determined from 412 Charolais cows to calculate their temperament score (TS). Based on the TS, calm (n = 55; TS, 1.09 ± 0.33) and temperamental (n = 58; TS, 2.27 ± 0.639) cows were selected and genotyped using a 248 single-nucleotide variation (SNV) panel. Of the 248 variations in the panel, only 151 were confirmed to be polymorphic (single-nucleotide polymorphisms; SNPs) in the tested population. Single-marker association analyses between genotypes and temperament measures (EV, PS and/or TS) indicated significant associations of six SNPs from four candidate genes. The markers rs109576799 and rs43696138, located in the DRD3 and HTR2A genes, respectively, were significantly associated with both EV and TS traits. Four markers, rs110365063 and rs137756569 from the POMC gene and rs110365063 and rs135155082 located in SLC18A2 and DRD2, respectively, were associated with PS. The variant rs110365063 located in bovine SLC18A2 causes a change in the amino acid sequence from Ala to Thr. Further studies are needed to confirm the association of genetic profile with cattle temperament; however, our study represents important progress in understanding the regulation of cattle temperament by different genes with divergent functions.

The aim of this study was to determine the semen quality, sexual behaviour and testosterone (T) levels in Saint Croix rams under semi-desert climate conditions. Sixteen rams (70.6 ± 12.5 kg; 24.1 ± 0.3 months old) were randomly divided into a grazing group (GG, n = 8) and a supplemented group (supplemented individually with 1 kg.d −1 of concentrate (156 g CP.kg −1 DM and 2.5 Mcal EM.kg −1 DM). SG, n = 8). Each group grazed on buffel, grass. Every two weeks, semen was collected, and sexual behaviour traits were evaluated. SG rams had greater body weight (P < 0.0001) and greater semen quality than the GG rams. SG rams had greater values for reaction time and lateral approaches than GG rams (P < 0.0001). No interaction was found between treatment and month for T concentration (P < 0.05); the SG rams had greater values during most of the months, but GG rams had greater values during September. Month had a significant effect on T concentration (P < 0.05) with the highest values in autumn. It can be concluded that Saint Croix rams are able to adapt to adverse environmental conditions and that supplementary feed prior to the mating season improves ram sexual behaviour.

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To evaluate the effect of oxytocin as a cervical dilator, a study was carried out on nulliparous goats inseminated transcervically at the beginning of the breeding season. One hundred sixteen nulliparous goats with a mean live weight of 33.4 ± 0.68 kg and an age of 13.7 ± 0.37 months were used. The goats were exposed to active bucks of proven fertility for a period of 14 d in order to induce oestrus. One week later, the Ovsynch protocol was applied, which consisted of the application of 20 mg of gonadorelin (Day Zero), 0.075 mg of cloprostenol (Day 7) and of a second dose of 20 mg of gonadorelin applied on Day 9. Artificial insemination (AI) was performed 16 hr later. Three treatments were evaluated: T1 = 50 IU saline, T2 = 25 IU oxytocin; T3 = 50 IU of oxytocin, intravenously applied 10–15 min before AI. The time required to inseminate each treated goat from groups T2 and T3 was 49.56 and 56.25 s, respectively, versus 85.78 s needed for the goats from group T1 (p < .0001). In the T1 group of goats, the insemination catheter was inserted 2.1 cm into the cervical canal and in goats from groups T2 and T3 it reached 3.41 and 3.77 cm into the cervical canal, respectively (p = .02). Pregnancy rates and prolificacy (kids/doe) were higher (p = .02) for groups T2 (82.93%; 1.16) and T3 (76.92%; 1.21) respectively than for control goats (61.11%; 0.69). In conclusion, the intravenous administration of oxytocin led to greater dilation and depth of cervical penetration, obtaining higher pregnancy rates and prolificacy.

R. Bras. Zootec., 49:e20180121, 2020 https://doi.org/10.37496/rbz4920180121Breeding and genetics Full-length research article Influence of temperament-related genes on live weight traits of Charolais cowsABSTRACT -We investigated whether a panel of molecular markers previously associated with temperament has an effect on live growth traits. Phenotypic data from 412 Charolais cows categorized according to their age in adult and young cows were used to determine Pearson's correlations between birth (BW), weaning (WW), and yearling live (YW) weight and temperament traits (measured as exit velocity [EV] and temperament score [TS]). For association analysis, selective genotyping of a group of 80 cows identified as the most docile and temperamental were genotyped with a 151-SNP (single-nucleotide polymorphisms) panel of molecular markers previously associated with temperament. Significant Pearson's correlations between birth weight and weaning weight and the two temperament measurements (EV and TS) were observed only in the young cow group. Significant effects of ten SNP on BW and WW were observed. Four markers located on candidate genes for temperament traits also had an effect on birth weight and weaning weight in Charolais cows, which indicates that both traits could be influenced by the same genes.How to cite: Garza-Brenner, E.; Sifuentes-Rincón, A. M.; Rodríguez-Almeida, F. A.; Randel, R. D.; Parra-Bracamonte, G. M. and Arellano-Vera, W. 2020. Influence of temperament-related genes on live weight traits of Charolais cows. Revista Brasileira de Zootecnia 49:e20180121.

Background: The search for gene and marker effects on economically important traits is aimed not only to understanding the genetic architecture of complex traits but also to applying the information to breeding schemes. Objective: To analyze the effect of two temperament-related SNPs (rs109576799 located in the DRD3 gene, and rs43696138 in the HTR2A gene) on feeding performance of Mexican beef cattle. Methods: One hundred and thirty-six young beef bulls were included in a centralized feed efficiency performance test based on residual feed intake (RFI), with 20 d for adaptation and 70 d of feed efficiency testing. In addition to feeding traits, temperament was assessed at the beginning of the trial using pen score (PS) and exit velocity (EV). All animals were genotyped with two markers located in the HTR2A and DRD3 genes, and an association analysis was conducted between these genotypes and the measured traits. Results: For Brangus breed, a significant association was obtained between average daily gain (ADG; p=0.019), and the rs43696138 marker, resulting in higher gains for homozygous genotype GG (1.69 ± 0.04 kg), when compared to the heterozygous genotype GA (1.54 ± 0.04 kg). Conclusion: The previously reported association of these markers with temperament was not confirmed in the evaluated breeds; however, the rs43696138 marker showed an effect on a feeding performance trait. Further studies are needed to determine the effect of this and other markers on both RFI and temperament.Keywords: beef cattle, feed efficiency, residual feed intake, single nucleotide polymorphism, temperament.  Resumen Antecedentes: La búsqueda de efectos genéticos y marcadores de rasgos económicamente relevantes no solo se basa en el interés biológico de comprender la arquitectura genética de rasgos complejos, sino también en aplicar la información en los esquemas prácticos de mejoramiento. Objetivo: Analizar el efecto de dos SNPs relacionados con el temperamento (rs109576799 localizado en el gen DRD3, y rs43696138 localizado en el gen HTR2A) sobre la eficiencia alimenticia en el ganado bovino mexicano. Métodos: Ciento treinta y seis toretes de carne jóvenes fueron sometidos a una prueba de comportamiento alimenticio basada en el consumo residual de alimento (RFI), con 20 d de adaptación y 70 d de prueba para la eficiencia alimenticia. Además de los rasgos de comportamiento alimenticio, se evaluó el temperamento de los animales al inicio de la prueba, mediante la evaluación de comportamiento en el corral (PS), y la velocidad de salida (EV). Todas las muestras se tipificaron con dos marcadores localizados en los genes DRD3 y HTR2A para posteriormente realizar un análisis de asociación de los genotipos con los rasgos evaluados. Resultados: En la raza Brangus, se observó una asociación significativa de la media de ganancia diaria de peso (ADG, p=0,019) con el marcador rs43696138, localizado en el gen HTR2A, resultando en mayores ganancias para el genotipo GG (1,69 ± 0,04 kg) en comparación con los toros heterocigóticos GA (1,54 ± 0,04 kg). Conclusión: No se confirmó la asociación de estos marcadores previamente reportados con el temperamento en las razas evaluadas; sin embargo, el marcador rs43696138 mostró efecto en un rasgo de comportamiento alimenticio. Se necesitan más estudios para determinar el efecto de éste y otros marcadores en el consumo residual de alimento (RFI) y el temperamento.Palabras clave: consumo residual de alimento, eficiencia alimenticia, ganado de carne, polimorfismo de un solo nucleótido, temperamento.  Resumo Antecedentes: A busca de efeitos genéticos e marcadores de características economicamente relevantes não se baseia apenas no interesse biológico de compreender a arquitetura genética de traços complexos, mas também na aplicação da informação nos esquemas práticos de melhoria. Objetivo: Analisar o efeito de dois SNPs relacionados ao temperamento (rs109576799 localizado no gene DRD3 e rs43696138 localizado no gene HTR2A) sobre a eficiência nutricional no gado mexicano. Métodos: Cento e trinta e seis touros jovens foram submetidos a um teste de comportamento alimentar com base na entrada de alimentação residual (RFI), com 20 d de adaptação e 70 d de teste para eficiência de alimentação. Além dos traços de comportamento alimentar, o temperamento dos animais foi avaliado no início do teste, através da avaliação do comportamento na caneta (PS) e da velocidade de saída (EV). Todas as amostras foram digitadas com dois marcadores localizados nos genes DRD3 e HTR2A para posteriormente realizar uma análise de associação dos genótipos com os traços avaliados. Resultados: Na raça Brangus, observou-se uma associação significativa do ganho diário médio (ADG, p = 0,019) com o marcador rs43696138, localizado no gene HTR2A, resultando em maiores ganhos para o genótipo GG (1,69 ± 0,04 kg), em comparação com os touros heterozigóticos GA (1,54 ± 0,04 kg). Conclusão: A associação destes marcadores previamente relatados com o temperamento nas raças avaliadas não foi confirmada; no entanto, o marcador rs43696138 mostrou um efeito sobre uma característica de comportamento alimentar. Mais estudos são necessários para determinar o efeito deste e outros marcadores com ingestão alimentar residual (RFI) e temperamento.Palavras-chave: consumo residual de alimentos, eficiência alimentar, gado bovino, polimorfismo de nucleotídeo único, temperamento.

The objective of this study was to evaluate the effect of supplementing 10% of sorghum grain (SG), soybean meal (SBM) or dried citrus pulp (DCP) upon dry matter digestibility (DMD), organic matter digestibility (OMD), and metabolizable energy content (ME) of diets based on dried leaves of two shrub species (Acacia farnesiana and Acacia rigidula) and one grass (Cenchrus ciliaris) browsed by small ruminants. Twelve experimental diets were elaborated using three forage sources: C. ciliaris, A. farnesiana and A. rigidula and evaluated either alone (0% supplementation) or supplemented with 10% of SG (9.0% CP, 22.3% NDF), SBM (42.8% CP, 16.3% NDF) or DCP (4.9% CP, 19.1% NDF). In vitro DMD (Daisy incubator, ANKOM) at 48 h, and in vitro gas production (GP, in calibrated 100 mL glass syringes) at 24 h, were determined by incubating samples in an inoculum prepared by using rumen liquor of two rumen fistulated sheep and artificial saliva in a 1:4 ratio. OMD and ME content were calculated from the gas production, crude protein, ash, and ether extract content. Data were evaluated according to a 3 x 4 factorial experiment. There were no significant (P &gt; 0.05) forage source x supplement interaction effects. Leaves of A. farnesiana had higher (P &lt; 0.05) DMD (64%), GP (26 mL), ME (1910 kcal ME/kg DM), and OMD (53%) than other forages (mean 47% DMD, 17 mL GP, 1232 kcal ME/kg DM, and 39% DMO). Supplements increased (P &lt; 0.05) DMD (average +8%), but only DCP increased (P &lt; 0.05) the GP (+23%) of evaluated forages. Leaves of A. farnesiana had higher DMD (P &lt; 0.05; 64%). There were no effects (P &gt;0.05) of the 10% added supplements in ME content or DMO. In conclusion, leaves of A. farnesiana and DCP are valuable sources of nutrients and energy for small ruminants in northeastern Mexico.

This study aimed to evaluate the effects of adding 0% (T1), 6% (T2), 12% (T3) and 18% (T4) of a mixture (83% dried citrus pulp (DCP) and 17% eggshell) into a sorghum-soybean meal-limestone based diet for laying quails, on production efficiency and quality of egg. Thirty-two quails were individually housed and randomly assigned (n = 8) to the four experimental diets, during the first 5 week of the laying cycle. Quail LW and feed intake were recorded weekly. Produced eggs were weighed (n = 457) and egg mass production recorded. Proportions of albumen, yolk and shell, egg yolk color, and shell thickness, were determined (n = 55/treatment). On week 5, total excreta of 24 laying quails (n = 6) were collected throughout 96 h, to determine metabolizable utilization of DM, energy, crude protein and ash. Statistical analyses were performed with SPSS® software. Initial and final LW, feed intake and egg production were similar (P &gt;0.05) among treatments. Egg mass was higher (P &lt; 0.05) in T2 than T4. Egg weight of quails fed T1 and T2 was higher than others (P &lt; 0.05). The eggshell of quails fed T2 was thicker (248 vs 236 μm; P &lt; 0.05) than T1. Eggshell proportion of quails fed the mixture was higher (P &lt; 0.05) than in T1 (11.3 vs 10.5%). Yolk proportion of T1 was higher (P &lt; 0.05). The b* parameter was lower (P &lt; 0.05) for T1. Metabolizable utilization of dietary DM (72.1%) and energy (68.8%) of T1 was 13% higher (P &lt; 0.05) than T4, however protein (avg 41.4%) and ash (avg 46.7%) utilization were similar (P &gt; 0.05) among treatments. In conclusion, adding up to 12% of the mixture (83% DCP and 17% eggshell) in quail diets, resulted in similar egg production parameters, and metabolizable utilization of dietary DM, crude protein, energy and ash, however improved thickness of eggshell, compared to the control diet.