RESUMO
This study aimed to investigate whether a specific genotype of the MTNR1A gene influences social dominance and reproductive performance in rams. Thirty-one rams were genotyped for Rsal and Mnll polymorphism of the gene: CC (n=19), CT (n=5), and TT (n=7), and GG (n=20), GA (n=6), or AA (n=5), respectively. Maintenance (standing still, lying down, drinking, feeding, walking, or stereotyping) and social behavior (agonistic and antagonistic interactions among rams) were recorded by direct observations involving instantaneous scan sampling and continuous behavior sampling. For each animal, his Index of Success (IS) and Displacement (ID) were calculated. One week after the social-behavioral observations, rams were tested in individual serving-capacity tests involving three ewes that were synchronized into estrus in a 15-m2 pen for 20 min. The genotypes did not differ in the number of aggressions they performed (CC: 88.95±12.85; CT: 106.20±21.00; TT: 70.43±8.50; GG: 76.05±8.72; GA: 119.00±16.16; AA: 95.80±36.39) or received (CC:75.79±5.82; CT:92.40±8.68; TT: 86.14±15.05; GG: 79.25±6.58; GA: 86.83±11.51; AA: 79.80±12.74), and their active and passive behaviors were similar. The genotypes did not differ significantly in IS or ID, and the proportion of rams in each success category was similar among groups. For the Rsal and Mnll polymorphism, TT and GG rams were responsible for 54% and 56% of recorded sexual events (P < 0.05), respectively. Results of this study confirm that the best sexual performance of rams was among those that carried certain genotypes of the MTNR1A gene. Still, it was not correlated with differences in social dominance.
Assuntos
Animais , Polimorfismo Genético , Comportamento Sexual Animal , Ovinos , Receptor MT1 de MelatoninaRESUMO
Thirty-nine autumn-born ram-lambs were used to study whether polymorphisms of the melatonin receptor 1A (MTNR1A) gene influence some reproductive parameters of Oct-born ram-lambs at 8 months of age. Animals were genotyped for their RsaI (CC, n=24; CT, n=6; TT, n=9) and Mn1I (GG, n=27; GA, n=6; AA, n=6) allelic variants of the MTNR1A gene. Liveweight (LW) was recorded bi-weekly until Jun, and scrotal perimeter (SP) was recorded once per month. From mid-Jan, blood samples were collected weekly to measure plasma testosterone concentrations. In mid-Jun, individual serving-capacity tests were performed. Testicular ultrasonography was performed at the end of the experiment. The effects of the week and gene polymorphism on LW, scrotal perimeter, and plasma testosterone concentrations were evaluated statistically by the GLM for repeated measures procedure. LW, SP, and plasma testosterone concentrations were significantly (P<0.001) affected by week, but neither of the polymorphisms of the melatonin receptor 1A (MTNR1A) gene affected these variables. In the serving tests, genotypes did not differ significantly in individual behaviors or the number of events (CC: 24.1±3.2, CT: 26.3±13.0, TT: 16.8±4.8, GG: 22.0±3.0, GA: 21.0±6.7, AA: 27.8±12.7). Testicular features assessed by ultrasonography did not differ significantly among genotypes. In conclusion, the polymorphisms of the melatonin receptor 1A (MTNR1A) gene did not have an effect on the reproductive characteristics of autumn-born ram lambs, based on serving capacity tests, testosterone secretion, and testicular measurements at 8 months of age.
Assuntos
Animais , Comportamento Sexual , Testículo , Testosterona , Ovinos , Receptor MT1 de MelatoninaRESUMO
Traditional knowledge about the behavior of grazing livestock is about to disappear. Shepherds well know that sheep behavior follows non-random patterns. As a novel alternative to seeking behavioral patterns, this study quantified the grazing activities of two sheep flocks of Churra breed (both in the same area but separated by 10 years) based on Global Position System (GPS) monitoring and remote monitoring sensing techniques. In the first monitoring period (2009-10), geolocations were recorded every 5 min (4,240 records), while in the second one (2018-20), records were taken every 30 min (7,636 records). The data were clustered based on the day/night and the activity (resting, moving, or grazing). An airborne LiDAR dataset was used to study the slope, aspect, and vegetation height. Four visible-infrared orthophotographs were mosaicked and classified to obtain the land use/land cover (LU/LC) map. Then, GPS locations were overlain on the terrain features, and a Chi-square test evaluated the relationships between locations and terrain features. Three spatial statistics (directional distribution, Kernel density, and Hot Spot analysis) were also calculated. Results in both monitoring periods suggested that the spatial distribution of free-grazing ewes was non-random. The flocks showed strong preferences for grazing areas with gentle north-facing slopes, where the herbaceous layer formed by pasture predominates. The geostatistical analyses of the sheep locations corroborated those preferences. Geotechnologies have emerged as a potent tool to demonstrate the influence of environmental and terrain attributes on the non-random spatial behavior of grazing sheep.
Assuntos
Animais , Ovinos/psicologia , Pastagens , Criação de Animais Domésticos/métodos , Dinâmica Populacional , Tecnologia de Sensoriamento Remoto/métodos , Tecnologia de Sensoriamento Remoto/veterináriaRESUMO
The objective of this study was to investigate the influence of meteorological and other factors on the quality and quantity of milk of the Spanish Churra sheep breed, based on an analysis of 359,808 milk controls from 9,904 ewes on 15 farms in 8 years. Daily milk yield (DMY), fat, protein, and lactose (%), and somatic cell count (SCC) data were obtained from monthly alternating milk controls. Mean, maximum, and minimum temperatures (T) (°C), mean relative humidity (RH) (%), wind speed (WS, m/s), mean solar radiation (SR, MJ/m2), and total rainfall (RF, mm) on the day before each milk control day were documented. Year, farm, number of lambing and stage of lactation, and all of the meteorological factors had asignificant (P < 0.0001) effect on DMY and milk quality. DMY and SCC differed among seasons (P < 0.001), and maximum DMY and minimum SCC occurred in spring, and minimum DMY and maximum SCC occurred in autumn. Fat, protein, and lactose content differed significantly (P < 0.001) among seasons, and fat and protein contents were highest in autumn. DMYwas highest in the second lambing of the ewe and steadily declined in subsequent lambings. SCC increased significantly from the first to the 10th lambing of the ewe. DMY, SCC, and fat content differed significantly (P < 0.001) among years. In conclusion, meteorological conditions had a significant effect on milk quality and production in Churra sheep conditions in a season-dependent manner such that factors such as temperature had the opposite effect on milk production in hot and cold seasons.(AU)
Assuntos
Animais , Feminino , Ovinos/metabolismo , Mudança Climática , Leite/químicaRESUMO
The objective of this study was to investigate the influence of meteorological and other factors on the quality and quantity of milk of the Spanish Churra sheep breed, based on an analysis of 359,808 milk controls from 9,904 ewes on 15 farms in 8 years. Daily milk yield (DMY), fat, protein, and lactose (%), and somatic cell count (SCC) data were obtained from monthly alternating milk controls. Mean, maximum, and minimum temperatures (T) (°C), mean relative humidity (RH) (%), wind speed (WS, m/s), mean solar radiation (SR, MJ/m2), and total rainfall (RF, mm) on the day before each milk control day were documented. Year, farm, number of lambing and stage of lactation, and all of the meteorological factors had asignificant (P < 0.0001) effect on DMY and milk quality. DMY and SCC differed among seasons (P < 0.001), and maximum DMY and minimum SCC occurred in spring, and minimum DMY and maximum SCC occurred in autumn. Fat, protein, and lactose content differed significantly (P < 0.001) among seasons, and fat and protein contents were highest in autumn. DMYwas highest in the second lambing of the ewe and steadily declined in subsequent lambings. SCC increased significantly from the first to the 10th lambing of the ewe. DMY, SCC, and fat content differed significantly (P < 0.001) among years. In conclusion, meteorological conditions had a significant effect on milk quality and production in Churra sheep conditions in a season-dependent manner such that factors such as temperature had the opposite effect on milk production in hot and cold seasons.
Assuntos
Feminino , Animais , Mudança Climática , Ovinos/metabolismo , Leite/químicaRESUMO
The objective of this study was to investigate the influence of meteorological and other factors on the quality and quantity of milk of the Spanish Churra sheep breed, based on an analysis of 359,808 milk controls from 9,904 ewes on 15 farms in 8 years. Daily milk yield (DMY), fat, protein, and lactose (%), and somatic cell count (SCC) data were obtained from monthly alternating milk controls. Mean, maximum, and minimum temperatures (T) (°C), mean relative humidity (RH) (%), wind speed (WS, m/s), mean solar radiation (SR, MJ/m2), and total rainfall (RF, mm) on the day before each milk control day were documented. Year, farm, number of lambing and stage of lactation, and all of the meteorological factors had asignificant (P < 0.0001) effect on DMY and milk quality. DMY and SCC differed among seasons (P < 0.001), and maximum DMY and minimum SCC occurred in spring, and minimum DMY and maximum SCC occurred in autumn. Fat, protein, and lactose content differed significantly (P < 0.001) among seasons, and fat and protein contents were highest in autumn. DMYwas highest in the second lambing of the ewe and steadily declined in subsequent lambings. SCC increased significantly from the first to the 10th lambing of the ewe. DMY, SCC, and fat content differed significantly (P < 0.001) among years. In conclusion, meteorological conditions had a significant effect on milk quality and production in Churra sheep conditions in a season-dependent manner such that factors such as temperature had the opposite effect on milk production in hot and cold seasons.(AU)
Assuntos
Animais , Feminino , Ovinos/metabolismo , Mudança Climática , Leite/químicaRESUMO
La estacionalidad de la reproducción es una característica de la mayoría de las razas caprinas y ovinas de latitudes subtropicales. Las hembras presentan anovulación y disminución de las concentraciones plasmáticas de LH en primavera y verano, mientras que los machos disminuyen drásticamente los niveles plasmáticos de testosterona, la producción espermática y el comportamiento sexual en invierno y primavera. Esta estacionalidad es sincronizada principalmente por las variaciones naturales del fotoperiodo. Sin embargo, las interacciones socio-sexuales entre machos y hembras permiten modificar esta estacionalidad. Así, la introducción de machos en grupos de hembras en anestro estacional estimulan las actividades endocrina y reproductiva de las hembras, através del fonómeno conocido como "efecto macho". La respuesta de las hembras al efecto macho varía con la intensidad del comportamiento sexual desplegado por los machos. Por ello, los machos sexualmente activos son más eficaces que los machos en reposo sexual para estimula la ovulación de las hembras. Además, la presencia continua de los machos sexualmente activos evita la anovulación estacional, así como la disminución estacional de las concentraciones plasmáticas de LH en hembras ovariectomizadas portadoras de implantes subcutáneos que liberan estradiol. En conjunto, estos hallazgos indican que los machos cabríos y carneros sexualmente activos son una alternativa para manipular la estacionalidad reproductiva de las hembras durante el anestro estacional, y/o evitar la anovulación estacional. Además, considerando las demandas sociales para reducir o eliminar los tratamientos hormonales en la producción animal, la asociación del fotoperiodo y las interacciones socio-sexuales entre machos y hembras constituye una alternativa sustentable para la manipulación de la actividad reproductiva de los pequeños rumiantes.
Assuntos
Animais , Hormônio Luteinizante/análise , Hormônio Luteinizante/química , Ovulação , Ruminantes/anatomia & histologia , Estações do Ano , Fotoperíodo , Ovinos , RuminantesRESUMO
Beef cows and ewes grazing native pastures are exposed to cycles of undernutrition that reflect the seasonal variations of biomass production. In grazing dairy cows, the physiological undernutrition during early lactation due to increased demands for lactation and low dry matter intake is exacerbated by the need to get sufficient intake from pasture and the extra grazing energy costs. Undernutrition has profound impacts on reproduction by affecting multiple reproductive processes at different levels of the reproductive axis. The objective of this paper is to review the influence of undernutrition on reproductive events of the adult female ruminant, with emphasis on both grassland and mixed rain-fed grazing farming systems. The comparative endocrinology and reproductive biology among ewes, beef and dairy cows may provide a comprehensive knowledge of the metabolic and reproductive adaptation to feed restriction. Understanding the critical underlying physiological mechanisms by which nutrition affects reproduction is the base of focus feeding strategy to improve the reproductive performance of the female ruminant.
RESUMO
Beef cows and ewes grazing native pastures are exposed to cycles of undernutrition that reflect the seasonal variations of biomass production. In grazing dairy cows, the physiological undernutrition during early lactation due to increased demands for lactation and low dry matter intake is exacerbated by the need to get sufficient intake from pasture and the extra grazing energy costs. Undernutrition has profound impacts on reproduction by affecting multiple reproductive processes at different levels of the reproductive axis. The objective of this paper is to review the influence of undernutrition on reproductive events of the adult female ruminant, with emphasis on both grassland and mixed rain-fed grazing farming systems. The comparative endocrinology and reproductive biology among ewes, beef and dairy cows may provide a comprehensive knowledge of the metabolic and reproductive adaptation to feed restriction. Understanding the critical underlying physiological mechanisms by which nutrition affects reproduction is the base of focus feeding strategy to improve the reproductive performance of the female ruminant.
Assuntos
Feminino , Animais , Bovinos/fisiologia , Bovinos/metabolismo , Ovinos/fisiologia , Ovinos/metabolismo , Endocrinologia , Ração AnimalRESUMO
Beef cows and ewes grazing native pastures are exposed to cycles of undernutrition that reflect the seasonal variations of biomass production. In grazing dairy cows, the physiological undernutrition during early lactation due to increased demands for lactation and low dry matter intake is exacerbated by the need to get sufficient intake from pasture and the extra grazing energy costs. Undernutrition has profound impacts on reproduction by affecting multiple reproductive processes at different levels of the reproductive axis. The objective of this paper is to review the influence of undernutrition on reproductive events of the adult female ruminant, with emphasis on both grassland and mixed rain-fed grazing farming systems. The comparative endocrinology and reproductive biology among ewes, beef and dairy cows may provide a comprehensive knowledge of the metabolic and reproductive adaptation to feed restriction. Understanding the critical underlying physiological mechanisms by which nutrition affects reproduction is the base of focus feeding strategy to improve the reproductive performance of the female ruminant.(AU)
Assuntos
Animais , Feminino , Ovinos/metabolismo , Ovinos/fisiologia , Bovinos/metabolismo , Bovinos/fisiologia , Ração Animal , EndocrinologiaRESUMO
A total number of 609 bulk-tank milk controls on a dairy sheep farm in Spain were used to determine how weather affects milk production in sheep, related to lambing period and lactation phase. Data from individuals were assigned to one of five lactation periods based on the timing of lambing: FEB (n=124); APR (n=141); JUL (n=114); SEP (n=102), and NOV (n=128). Milk yield per ewe per day was calculated as total milk volume/number of ewes milked. Lactation was divided into three phases: Early-lactation (from lambing to month 2), Mid-lactation (from month 3 to 7), and Late-lactation (month 8). Milk yield per ewe was higher (P<0.01) in SEP than in FEB, APR, or NOV; production peaked in JUL and was lowest in FEB. In lactations initiated in JUL and SEP, milk yield per ewe per day was higher (P<0.05) in early lactation than it was in the other lambing periods; however, in APR and SEP, per ewe production was highest (P<0.01) in mid-lactation. Milk yield in each of the five lambing periods was significantly (P=0.001) associated with several meteorological variables, and the strongest (R2 =0.732) was with solar radiation and minimum temperature in the APR lactation period. In all lactation periods, the relationship between milk yield and weather differed among the three phases of lactation. In conclusion, the effects of meteorological conditions on milk yield in sheep cannot be understood without assessing production among milking periods in the same year and the phases of lactation, especially if milking periods are long.
Assuntos
Animais , Lactação , Ovinos , Tempo (Meteorologia) , PartoRESUMO
A total number of 609 bulk-tank milk controls on a dairy sheep farm in Spain were used to determine how weather affects milk production in sheep, related to lambing period and lactation phase. Data from individuals were assigned to one of five lactation periods based on the timing of lambing: FEB (n=124); APR (n=141); JUL (n=114); SEP (n=102), and NOV (n=128). Milk yield per ewe per day was calculated as total milk volume/number of ewes milked. Lactation was divided into three phases: Early-lactation (from lambing to month 2), Mid-lactation (from month 3 to 7), and Late-lactation (month 8). Milk yield per ewe was higher (P<0.01) in SEP than in FEB, APR, or NOV; production peaked in JUL and was lowest in FEB. In lactations initiated in JUL and SEP, milk yield per ewe per day was higher (P<0.05) in early lactation than it was in the other lambing periods; however, in APR and SEP, per ewe production was highest (P<0.01) in mid-lactation. Milk yield in each of the five lambing periods was significantly (P=0.001) associated with several meteorological variables, and the strongest (R2 =0.732) was with solar radiation and minimum temperature in the APR lactation period. In all lactation periods, the relationship between milk yield and weather differed among the three phases of lactation. In conclusion, the effects of meteorological conditions on milk yield in sheep cannot be understood without assessing production among milking periods in the same year and the phases of lactation, especially if milking periods are long.(AU)
Assuntos
Animais , Ovinos , Lactação , Tempo (Meteorologia) , PartoRESUMO
The aim of this study was to determine the effect of temperature on the day of artificial insemination (AI) on fertility, and to study how climate zone of the farm may modify this effect, in two breeds of sheep that are reared on the Iberian Peninsula on four farms located within one of three climate zones, based on the Köppen Climate Classification. A total number of 1,931 AI were studied from Spanish farms of the Rasa Aragonesa (RA) (July) and Churra (CH) (June) breeds. Farms were categorized as Köppen BSk (Farm BSkRA; n=229), and Köppen Cfb (Cfb-RA; n=372), Köppen Csb (Csb-CH; n=908), and Köppen Cfb (Cfb-CH; n=422). Mean, maximum, and minimum temperatures (°C) were recorded, and thermal amplitude (maximum-minimum temperatures) calculated. Each set of temperature data was distributed between percentile-groups (≤50% and >50%), below or above the median. Temperatures at AI were higher (P50 percentile groups indicated that inseminations performed when temperatures were within the >50 percentile had a higher proportion (P1 for one or more of the meteorological variables under study; meanwhile, in the other two climates, OR were 0.05). In conclusion, the effects of temperature on fertility after AI differed depending on the climate zone in which the flocks were reared. The results have implications for the scheduling of insemination dates to achieve the maximal performances.
Assuntos
Feminino , Animais , Efeitos do Clima/análise , Espanha , Inseminação Artificial/métodos , Inseminação Artificial/veterinária , Ovinos/fisiologia , Zonas ClimáticasRESUMO
The aim of this study was to determine the effect of temperature on the day of artificial insemination (AI) on fertility, and to study how climate zone of the farm may modify this effect, in two breeds of sheep that are reared on the Iberian Peninsula on four farms located within one of three climate zones, based on the Köppen Climate Classification. A total number of 1,931 AI were studied from Spanish farms of the Rasa Aragonesa (RA) (July) and Churra (CH) (June) breeds. Farms were categorized as Köppen BSk (Farm BSkRA; n=229), and Köppen Cfb (Cfb-RA; n=372), Köppen Csb (Csb-CH; n=908), and Köppen Cfb (Cfb-CH; n=422). Mean, maximum, and minimum temperatures (°C) were recorded, and thermal amplitude (maximum-minimum temperatures) calculated. Each set of temperature data was distributed between percentile-groups (≤50% and >50%), below or above the median. Temperatures at AI were higher (P50 percentile groups indicated that inseminations performed when temperatures were within the >50 percentile had a higher proportion (P1 for one or more of the meteorological variables under study; meanwhile, in the other two climates, OR were <1 (P>0.05). In conclusion, the effects of temperature on fertility after AI differed depending on the climate zone in which the flocks were reared. The results have implications for the scheduling of insemination dates to achieve the maximal performances.(AU)