Abstract Reviewing the current state of knowledge on reproductive performance and productive traits in rams has many advantages. First, the compilation of this information will serve as a literature resource for scientists conducting research around the world and will contribute to the understanding of the data collected and interpreted by researchers on the different hormonal strategies used to improve reproductive performance in rams. Second, it will allow scientists to identify current knowledge gaps and set future research priorities in ram reproduction. Rams play an important role in the global flock economy, but their reproductive analysis has been limited in the use of hormonal technologies to increase the productivity of sheep flocks. In this review, we cite the most important works on six hormones that, in one way or another, modify the hypothalamus-pituitary-gonadal axis, at different doses, in and out of the reproductive season, breeds, application methods, among other factors. The overall aim is to increase the reproductive efficiency of rams in different scenarios and, in some cases, of other species due to the lack of limited information on rams. advantages First Second reproduction economy flocks review that another hypothalamuspituitarygonadal hypothalamus pituitary gonadal axis doses season breeds methods factors cases

Abstract The objective of the study was to evaluate the effect of feeding finishing pigs with a wet diet (feed:water, 1:1), versus a dry diet based on sorghum and soybean meal (15.0% CP, 3,200 kcal ME/kg DM), on the productive behavior, carcass composition and meat quality. Sixteen (York-Landrace x Duroc) crossbred pigs weighing 68.4 ± 2.4 kg were individually housed and assigned to two treatments (n= 8 replicates per treatment): DF, dry feed; WF, wet feed. Feed was offered daily in two equal portions (0800 and 1500 h) for 5 wk. Individual live weight (LW) and feed consumption were recorded every week in order to calculate the daily weight gain (DWG) and feed efficiency (FE). The carcass composition was measured; the meat quality was assessed in samples of Longissimus dorsi. Wet-fed pigs had higher (P<0.05), final LW (108.4 vs 101.9 kg), and DWG (1.043 vs. 0.990 kg/day) than dry-fed pigs. DF pigs had lower intake (wk 5) and feed efficiency (FE) (by wk 3) than WF pigs (Treatment x Week Interaction, P<0.05). WF pigs had greater leg and hot and cold carcass weights (P<0.05). The weight of the loin, ribs, and shoulder, and the protein content, water holding capacity, and pH of meat were similar (P>0.05) between treatments. The hardness, adhesiveness, chewiness, and toughness values were lower (P<0.05) in meat from WF pigs. In conclusion, the wet-fed pigs had better productive performance, carcass composition and meat characteristics than the dry-fed pigs.

Resumen El objetivo del estudio fue evaluar el efecto de la alimentación húmeda de cerdos en finalización (alimento:agua, 1:1) de una dieta basada en sorgo y harina de soya (15.0% PC, 3,200 kcal EM/kg MS), sobre el comportamiento productivo, composición de la canal y calidad de la carne. Dieciséis cerdos cruzados (York-Landrace x Duroc) de 68.4±2.4 kg de peso fueron alojados individualmente, y asignados a dos tratamientos (n=8 repeticiones por tratamiento): AS, alimentación seca; AH, alimentación húmeda. Alimento fue ofrecido diariamente en dos porciones iguales (0800 y 1500 h) durante cinco semanas. Semanalmente se registraron el peso vivo (PV) y el consumo de alimento individuales, para calcular ganancia diaria de peso (GDP) y eficiencia alimenticia (EA). Se midió la composición de la canal; la calidad de la carne fue medida en muestras de Longissimus dorsi. Cerdos AH tuvieron mayor (P<0.05) PV final (108.4 vs 101.9 kg) y GDP (1.043 vs 0.990 kg/día) que los cerdos AS. Cerdos AS tuvieron menor consumo (semana 5) y EA (semana 3) que los cerdos AH (Interacción Tratamiento x Semana, P<0.05). Cerdos AH tuvieron pesos mayores de pierna, canal caliente y fría (P<0.05). Lomo, costillas, paleta, contenido de proteína, capacidad de retención de agua y pH de la carne fueron similares (P>0.05) entre tratamientos. Valores de dureza, adhesividad, masticabilidad y resistencia fueron menores (P<0.05) en carne de cerdos AH. En conclusión, los cerdos que recibieron alimento húmedo tuvieron mejor comportamiento productivo, composición de la canal y características de la carne que cerdos que recibieron alimento seco.

Abstract 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.

ABSTRACT The effect of three localized genetic markers in growth hormone (GH), Insulin-like growth factor 1 (IGF-1) and leptin (LEP) genes on feed efficiency indicators was evaluated using records from 136 young bulls of the Charolais, Angus and Brangus breeds during a productive behavior test. The analysis of association between the genotypes obtained and the productive traits evaluated showed a significant effect of the GH-Alu marker on CRA (p = 0.032) in the Angus breed, and in the Charolais one; this result shows that its inclusion in the initial efforts for the determination of efficiency phenotypes in Mexico and its consequent application in selection and breeding strategies are possible.

RESUMEN Se evaluó el efecto de tres marcadores genéticos localizados en los genes de hormona de crecimiento (GH), factor de crecimiento semejante a insulina-1 (IGF-1) y leptina (LEP) sobre indicadores de eficiencia alimenticia, utilizando registros de 136 toretes de las razas Charolais, Angus y Brangus durante una prueba de comportamiento productivo. El análisis de asociación entre los genotipos obtenidos y los rasgos productivos evaluados mostró un efecto significativo del marcador GH-Alu sobre CRA (p = 0.032) en la raza Angus, y sobre el peso final ajustado (p = 0.041), en la Charolais; este resultado muestra que es posible su inclusión en los esfuerzos iniciales para la determinación de fenotipos de eficiencia en México y su consecuente aplicación en las estrategias de selección y mejoramiento genético.

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 evaluacion 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.

Abstract 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.

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.