Five Argentine Pampinta (dairy breed) and six Corriedale (dual-purpose breed) adult rams were used to study the effect of season on sexual behavior, plasma testosterone (T) and semen characteristics for a period of 1 year. Scrotal circumference (SC) and T concentrations were determined at 2-week intervals. Each ram was exposed monthly to three ovariectomized ewes in one 20-min test and the total number of mounts and successful matings were recorded. Semen collection was attempted from each ram twice weekly for six consecutive weeks during each season. In both breeds, SC varied seasonally showing the lowest mean values during winter and spring and in the Corriedale rams (32.8 ± 0.3 cm) was smaller (p < 0.05) than in Pampinta rams (34.4 ± 0.4 cm). No difference (p > 0.05) was recorded in T concentration between breeds and both breeds reached a peak in summer and autumn. Number of matings showed the maximal values in autumn in both breeds. Season had no significant effect on mass motility, sperm concentration and percentage of live sperm. Semen volume, percentage of progressive motility and total sperm per ejaculate were higher during summer and autumn than in other seasons of the year. Pampinta rams had the highest values (p < 0.05) of sperm concentration, total sperm per ejaculate and percentage of abnormal sperm. Results of this study show that sexual behavior, SC and T concentrations exhibit seasonal variation in Pampinta and Corriedale rams and that semen of superior quantity and quality is especially collected in both breeds during the summer and autumn.Additional key words: hormone, rams; semen quality; serving capacity. Resumen Variación estacional en el comportamiento sexual, testosterona plasmática y características seminales de carneros Pampinta Argentina y CorriedaleCinco carneros adultos Pampinta Argentina (raza lechera) y seis Corriedale (raza doble propósito) fueron utilizados para estudiar el efecto de la estación del año sobre el comportamiento sexual, testosterona plasmática (T) y caracterís-ticas seminales. La circunferencia escrotal (CE) y las concentraciones de T fueron determinadas cada dos semanas. Mensualmente, cada carnero fue expuesto a tres ovejas ovariectomizadas en una prueba de 20 min y se registró el número total de montas y apareamientos. La colección del semen fue intentada dos veces por semana por seis semanas consecutivas durante cada estación. En ambas razas los menores valores de CE fueron observados en invierno y primavera (Corriedale = 32,8 ± 0,3 cm; Pampinta = 34,4 ± 0,4 cm; p < 0,05). La concentración de T alcanzó un máximo en verano y otoño y el número de apareamientos fue máximo en otoño. La estación no tuvo efecto (p > 0,05) sobre la motilidad masal, la concentración espermática y el porcentaje de espermatozoides vivos. El volumen del eyaculado, el porcentaje de motilidad progresiva y el número total de espermatozoides fueron mayores en el verano y otoño. La raza del carnero tuvo un efecto (p < 0,05) sobre la concentración espermática, el número total de espermato...
Analyses were made on birth weight of 2706 kids (six genetic groups) under confinement conditions in the arid zone of northern Mexico, to study the effect of air temperature (mean annual temperature l 21n1 mC) during gestation on this trait. The relationship of environmental temperature at kidding and survival of kids was also studied. Birth weight was significantly negatively related to mean dry bulb air temperature during gestation (reduction of 40p3 g for 1 mC increase in mean air temperature during gestation ; r lk0n22 ; P 0n01), although temperature only explained 5 % of the variance of kid birth weight. Mean minimum temperatures ( 4 mC) 5 days after birth significantly reduced kid survival (83 % v. 89-93 % for kids born when temperatures were above 4 mC; P 0n01). Air temperatures between 30 and 41 mC during the perinatal period did not affect (P 0n05) survival rate. These results suggest that newborn kids seem to be relatively resistant to high air temperature, but are fairly susceptible to cold stress. Also, birth weight of kids from goats exposed to high air temperature during pregnancy was marginally reduced, although this was of limited economic significance.
Throughout the world, livestock grazing systems (LGS) include, and provide livelihoods for, many rural populations. These LGS are represented in a wide variety of agroecological contexts and offer a huge variety of system organization. They contribute to sustainable food systems by providing multiple products including low-cost edible proteins and energy, draft power, outputs (carbon and soil nutrient regulation, landscape and biodiversity maintenance), roles (local development support in harsh environments, contribution to the circular economy) and benefits to populations (revenue, employment, and cultural assets). These multiple functions can be described through a multifunctional conceptual model specified for LGS. Applied to cases in Africa, Asia, Latin America and Europe, the framework enables the assessment of these systems in a holistic manner that includes four dimensions: production, social, environmental and local development. These dimensions and associated local indicators demonstrate the potential important contribution that LGS may deliver to sustainable food systems. Management of interactions and trade-offs between these functions may be improved using such a model in a multi-stakeholder approach. Some of the functions and balance between them might have been overlooked in the consideration of European food systems.
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