Bioestimulación o efecto macho

[email protected]@csu.edu.a

Reproductive and maternal behavior of livestock

This chapter describes the reproductive and maternal behaviors of different livestock species (cattle, horses, pigs, goats, and water buffalo) with an emphasis on those traits which are genetically conserved. All of the species discussed are polygynous and promiscuous, and females undergo estrous cycles in which males are mainly attracted by movement and posture cues. Major differences in both reproductive and maternal behaviors are observed between "prey" and "predator" type species. Genetic variation also occurs within species, with breed and line differences being observed in all of the behaviors discussed, allowing selection for optimal reproductive and maternal behaviors. However, modern livestock systems, which emphasize production traits, can diminish reproductive and maternal traits and increase detrimental behaviors, such as piglet crushing and savaging in sows. With modern selection tools, greater emphasis on positive reproductive and maternal traits is achievable within the context of profitable production

Biostimulation and pheromones in livestock: A review

This review examines aspects of the phenomenon of biostimulation in swine, goats, sheep, cattle and deer, to improve the collective knowledge and exploitation of its relevant mechanisms and effects in animal production. The long-term goal is to implement biostimulation strategies that benefit livestock reproduction and production while being both cost-effective and socially acceptable

About the inconvenience of handling mixed-breed herds; aspects of social behavior as a potential source of stress and economic losses

The objective of this study was to assess aspects of the social behavior of a mixed-breed herd of beef cows as a potential source for stress and economic losses. Angus (AN; N = 10), Brahman (BR; N = 10), and Senepol (SE; N = 10) cows were assigned to two groups (N = 15 each containing equal breed numbers) on separate pastures. Agonistic interactions (win/loss) during feeding were recorded daily for 45 days. Dominance values were estimated as the proportion of individuals dominated to total herdmates. From this, individuals were placed into social categories based upon linear ranking as follows: dominants (D), intermediate (I), and subordinates (S). Breed influenced (P < 0.01) social category, with SE cows being dominants (P < 0.05) over AN and BR cows. Interactions between AN and BR cows were less (P < 0.0005) than interactions between AN and SE (53 vs 140, respectively). Within breeds, BR (152) and SE (182) cows had more (P < 0.0005) agonistic interactions than AN (107) cows. Although apparently influenced by breed, agonistic interactions occurred more frequently (P < 0.005) between social categories than within social categories (814 vs 310, respectively). Dominant cows were involved in more agonistic interactions with cows from different social categories than were intermediate and subordinate cows (P < 0.0005). However, intermediate (100) and subordinate (157) cows generated more (P < 0.0005) agonistic interactions within their own social category than dominant cows (53). It was concluded that, in mixed-breed herds, breed influences both social organization and agonistic interactions which could be considered as potential sources of stress and economic losses

Identifying the social dominance order in a mixed breed herd: A practical methodology

Con el objetivo de identificar un método simple y confiable para evaluar diferencias en el status social, se compararon 3 métodos para estimar el valor de dominancia (DV) en vacas de tres razas cárnicas: Angus (A; n=10), Brahman (B; n=10) y Senepol (S; n=10). Las vacas fueron distribuidas en dos grupos de 15 animales, en potreros separados y conteniendo cada grupo la misma cantidad de animales de cada raza. Las interacciones agonistas ocurridas durante cada período de suplementación fueron recopiladas durante 45 d, en sesiones de 1 h y dos veces al día, usando el método del orden competitivo ganador/ perdedor. Los métodos para estimar DV incluyeron: I) Proporción entre individuos dominados y total de enfrentados, II) proporción entre encuentros ganados y total de encuentros, III) proporción de individuos dominados y total de individuos en el rebaño. Debido a los diferentes niveles de interactividad evidenciados entre animales, así como entre y dentro de categorías sociales, el método III con subsiguiente transformación Arc-sin fue considerado el más práctico y preciso, tanto para la estimación de DV como para la posterior organización de un orden de dominancia social. Adicionalmente, se halló que la dominancia social fue influenciada por la raza. Las vacas Senepol (1.24 ± 0.08) obtuvieron mayores valores de dominancia que las Angus (0.97 ± 0.08; P<0.03) y Brahman (0.76 ± 0.08; P<0.005).148 - 154BimestralThe major objective of this study was to identify a simple and accurate method of assessing differences in female social status. Three methods of estimating dominance value (DV) were compared in beef cows of three breed-types; Angus (A; n=10), Brahman (B; n=10), and Senepol (S; n=10). Cows were equitably assigned to two groups of fifteen each, allocated into separate pastures and containing equal number of animals by breed. Agonistic interactions were recorded for 45 d of study, in two 1 h periods during concentrate feeding using the method of competitive orders winner/loser. Methods of estimating DV included: I) Ratio between individuals dominated and total encountered, II) Ratio between encounters won to total encounters, III) Proportion of individuals dominated to total herdmates. Due to the different level of interactivity evidenced among animals as well as between and within social orders, method III with subsequent arc-sin transformation was considered as the most practical and accurate method for estimating DV and subsequent allocation of cows into a social dominance order. In addition, a breed effect was found on social dominance. Senepol cows obtained greater DV´s (1.24 ± 0.08) than Angus (0.97 ± 0.08; P<0.03) and Brahman cows (0.76 ± 0.08; P<0.005)

Techical Note: Preweaning growth of nontraditional crossbred F1 beef cattle. Preliminary results

A objeto de evaluar el crecimiento predestete de mestizos F1 de las razas Simmental (SM), Belgian Blue (BB), Beefmaster una finca comercial del Estado Zulia, Venezuela. En condiciones de trópico subhúmedo, los terneros fueron pesados al nacer y cada treinta días hasta el deteste, obteniéndose pesos al nacer de 36.0 ± 5.1, 38.6 ± 6.3, 32.7 ± 4.1 y 32.7 ± 6.0 kg.; ganancia de peso predestete de 368, 369, 377 y 330 g/d; pesos ajustados a 205 días de 118.1 ±37, 119.4 ± 27.6, 110.0 ± 21.9 y 101.0 ± 17.2 kg, ± 17.2 kg, y tasas de crecimiento hasta 205 días de 228.0, 209.3, 236.1 y 208.8% para los F1 (SM), (BB), (BM) y (LM), respectivamente. Los pesos al nacer se consideraron buenos, no así las ganancias de pero, el peso al destete y las tasas de crecimiento predestete, las cuales sugieren una subutilización del potencial de crecimiento de los genotipos en estudio, posiblemente debido a efectos ambientales. El análisis del crecimiento predestete en etapas intermedia entre el nacimiento y el destete evidenció puntos críticos en la fase de cría, no observables mediante la curva de crecimiento continua.165 - 174CuatrimestralIn order to evaluate the preweaning growth of F1 crossbred Simmental (SM), Belgian Blue (BB), Beefmaster (BM) and Limousine (LM), mating plans were programmed in a commercial farm at Zulia State, Venezuela, under a subhumid tropical forest. Calves were weight at birth and every thirty days up to weaning. Birth weights were 36.0 ± 5.1, 38.6 ± 6.3, 32.7 ± 4.1 and 32.7 ± 6.0 kg.; AGD were 368, 369, 377 and 330 g/d; ajusted 205 d wt. were 118.1 ±37, 119.4 ± 27.6, 110.0 ± 21.9 and 101.0 ± 17.2 kg, ± 17.2 kg, and growth rate was 228.0, 209.0, 236.0 and 208.0% respectively for SM, BB, BM and LM. Birth weight were considered good, nevertheless, ADG, weaning weight and preweaning growth rate were low, by suggesting subutulization of the genotypes growth potential probably due to environmental factors. Preweaning growth analyses at different stages of growth between birth and weaning indicated critical points at breeding phase, nonobservant throughout the continuous growth curve

Effect of season and genotype on values for bull semen variables under tropical conditions

To assess the effects of season and genotype on fresh semen quality for freezing and subsequent use for AI, 32 healthy, mature (>4 to 0.05). Season affected EV (P 0.05). It is concluded that in tropical regions, season and genotype can affect bull semen variables, particularly those which affect the success of semen freezing and AI

Contemporary use of cefazolin for MSSA infective endocarditis: analysis of a national prospective cohort

Objectives: This study aimed to assess the real use of cefazolin for methicillin-susceptible Staphylococcus aureus (MSSA) infective endocarditis (IE) in the Spanish National Endocarditis Database (GAMES) and to compare it with antistaphylococcal penicillin (ASP). Methods: Prospective cohort study with retrospective analysis of a cohort of MSSA IE treated with cloxacillin and/or cefazolin. Outcomes assessed were relapse; intra-hospital, overall, and endocarditis-related mortality; and adverse events. Risk of renal toxicity with each treatment was evaluated separately. Results: We included 631 IE episodes caused by MSSA treated with cloxacillin and/or cefazolin. Antibiotic treatment was cloxacillin, cefazolin, or both in 537 (85%), 57 (9%), and 37 (6%) episodes, respectively. Patients treated with cefazolin had significantly higher rates of comorbidities (median Charlson Index 7, P <0.01) and previous renal failure (57.9%, P <0.01). Patients treated with cloxacillin presented higher rates of septic shock (25%, P = 0.033) and new-onset or worsening renal failure (47.3%, P = 0.024) with significantly higher rates of in-hospital mortality (38.5%, P = 0.017). One-year IE-related mortality and rate of relapses were similar between treatment groups. None of the treatments were identified as risk or protective factors. Conclusion: Our results suggest that cefazolin is a valuable option for the treatment of MSSA IE, without differences in 1-year mortality or relapses compared with cloxacillin, and might be considered equally effective