RESUMEN
BACKGROUND: Sensory Bias models for the evolution of mate preference place a great emphasis on the role of sensory system variation in mate preferences. However, the extent to which sensory systems vary across- versus within-species remains largely unknown. Here we assessed whether color vision varies in natural locations where guppies (Poecilia reticulata) and their two closest relatives, Poecilia parae and Poecilia picta, occur in extreme sympatry and school together. All three species base mate preferences on male coloration but differ in the colors preferred. RESULTS: Measuring opsin gene expression, we found that within sympatric locations these species have similar color vision and that color vision differed more across populations of conspecifics. In addition, all three species differ across populations in the frequency of the same opsin coding polymorphism that influences visual tuning. CONCLUSIONS: Together, this shows sensory systems vary considerably across populations and supports the possibility that sensory system variation is involved in population divergence of mate preference.
Asunto(s)
Evolución Biológica , Visión de Colores , Poecilia/clasificación , Poecilia/genética , Animales , Femenino , Proteínas de Peces/genética , Frecuencia de los Genes , Masculino , Preferencia en el Apareamiento Animal , Opsinas/genética , Poecilia/fisiología , Polimorfismo Genético , América del Sur , SimpatríaRESUMEN
The breeding soundness evaluation (BSE) was used to evaluate Senepol (Bos taurus) bulls (n = 495) on St. Croix over a 7-year period. Young, unproven bulls (10-26 months of age) and breeding bulls (16 months to 8.5 years) were tested prior to sale or use in breeding. Inbreeding coefficients were determined for a subset of bulls (n = 290). The percentage of bulls passing the BSE increased (P < 0.0001) with age. Bulls that passed had a higher percentage (P < 0.0001) of normal and motile sperm as well as a larger (P < 0.0001) scrotal circumference than bulls that failed. No bulls failed the BSE for physical soundness traits or other health reasons. The incidence of testicular hypoplasia was 2.5 and 3.3% and the incidence of cryptorchidism was 1.4 and 0.9% in 12- and 16-month-old bulls, respectively, with no occurrence in bulls >20 months. The proportion of all bulls that failed the BSE and received an Unsatisfactory rating for scrotal circumference or sperm motility decreased (P < 0.0001) from >90 to <25% with age. The proportion of all bulls that failed the BSE and received an Unsatisfactory rating for sperm morphology decreased (P < 0.0001) from 99 to 83.3% with age. The inbreeding coefficient was higher (P < 0.03) in bulls that failed the BSE than in those that passed (2.24 +/- 0.19% versus 1.40 +/- 0.32%, respectively). There was a tendency for bulls with testicular hypoplasia or cryptorchidism to have a higher (P = 0.09) inbreeding coefficient than bulls with normal testes (2.90 +/- 0.46% versus 2.13 +/- 0.11%, respectively). In conclusion, Senepol bulls raised under tropical conditions had a low probability of passing the BSE at young ages, but the passing rate increased with age. Older Senepol bulls were more likely to fail the BSE due to abnormal sperm morphology than due to inadequate testicular size or sperm motility. To prevent unnecessary culling, a BSE should not be performed on Senepol bulls <16 months old.
Asunto(s)
Cruzamiento , Bovinos/fisiología , Animales , Criptorquidismo/epidemiología , Criptorquidismo/veterinaria , Endogamia , Masculino , Escroto/anatomía & histología , Motilidad Espermática , Espermatozoides/anomalías , Testículo/patología , Islas Virgenes de los Estados UnidosRESUMEN
Pregnant St. Croix White and Barbados Blackbelly hair sheep ewes were used to evaluate the effect of supplemental nutrition around the time of lambing on ewe and lamb performance during the dry and wet seasons on St. Croix. Beginning 14 d before expected day of lambing (d 0) and for 21 d postpartum, one group of ewes was fed a pelleted supplement in addition to grazing guinea grass pasture (FEED). Other ewes in the flock grazed pasture only (CONTROL). This study was conducted during the dry season (June through September; FEED n = 14 and CONTROL n = 15) and during the wet season the next year (October through January; FEED n = 11 and CONTROL n = 12). The 24-h milk production of each ewe was measured on d 7, 21, 35, 49, and 63. Ewes were exposed to sterile rams equipped with marking harnesses to detect estrus during the postpartum period. The FEED ewes lost less weight postpartum during both seasons (P < 0.0001) and had higher milk production (P < 0.009) than CONTROL ewes during the dry season. During the dry season, the time to the first postpartum estrus did not differ (P > 0.10) between FEED and CONTROL ewes (46.9 +/- 2.7 vs 52.9 +/- 2.6 d, respectively). During the wet season, the time to first postpartum estrus was less (P < 0.07) in FEED than in CONTROL ewes (33.0 +/- 3.1 vs 41.1 +/- 2.9 d, respectively). The FEED ewes had higher lamb birth weight (P < 0.04) and weaning weight (P < 0.05) than CONTROL ewes (3.2 +/- 0.1 and 12.2 +/- 0.5 vs 2.9 +/- 0.1 and 10.9 +/- 0.5 kg, respectively) during the dry season. In the wet season, lamb birth weight and weaning weight were similar (P > 0.10) between FEED and CONTROL (3.2 +/- 0.1 and 15.5 +/- 0.7 vs 3.1 +/- 0.1 and 15.3 +/- 0.6 kg, respectively). Lambs born during the wet season had higher (P < 0.0001) ADG than lambs born during the dry season (194.4 +/- 5.9 vs 127.7 +/- 4.7 g/d, respectively). Strategic nutritional supplementation of hair sheep ewes may provide a method for increasing the weight of lambs produced during the dry season in the tropics, but it does not seem to be beneficial during the wet season.
Asunto(s)
Alimentación Animal , Fenómenos Fisiológicos Nutricionales de los Animales , Animales Lactantes/crecimiento & desarrollo , Lactancia/fisiología , Leche/metabolismo , Ovinos/fisiología , Animales , Peso al Nacer , Peso Corporal , Suplementos Dietéticos , Estro/fisiología , Femenino , Poaceae , Periodo Posparto , Embarazo , Estaciones del Año , Factores de Tiempo , Islas Virgenes de los Estados Unidos , DesteteRESUMEN
Hair sheep ewes (St. Croix White and Barbados Blackbelly) were used to evaluate 3 methods of estrus synchronization for use with transcervical artificial insemination (TAl). To synchronize estrus, ewes (n=18) were treated with PGF2alpha (15 mg, im) 10 d apart, with controlled internal drug release (CIDR) devices containing 300 mg progesterone for 12 d (n=18), or with intravaginal sponges containing 500 mg progesterone for 12 d (n=18). On the day of the second PGF2alpha injection or at CIDR or sponge removal, sterile rams were placed with the ewes. Jugular blood samples were collected from the ewes at 6-h intervals until the time of ovulation, and daily for 16 d after estrus (Day 0). Plasma was harvested and stored at -20 degrees C until LH, and progesterone concentrations were determined by RIA. There was no difference (P>0.10) in time to estrus among the CIDR-, PGF2 alpha- or sponge-treated ewes. All of the ewes in the CIDR group and 94.4 percent of the sponge treated ewes exhibited estrus by 36 h after ram introduction, while only 72.2 percent of PGF2alpha-treated ewes showed signs of estrus by this time (P<0.06). The time from ram introduction to ovulation was not different (P>0.10) among CIDR, PGF2alpha- or sponge-treated ewes. The time to preovulatory LH surge was similar (P>0.10) among treatment groups. Hair sheep ewes (n=23) were synchronized using PGF2alpha and bred by TAI using frozen-thawed semen 48 h after the second injection. The conception rate to TAI was 2/23 (8.7 percent) and produced 3 ram lambs. In a subsequent trial, 17 ewes were synchronized with CIDR devices and bred by TAI using frozen-thawed semen 48 h after CIDR removal, resulting in a conception rate of 52.9 percent (9/17). It is possible to synchronize estrus in hair sheep using either CIDRs, sponges or PGF2alpha. Even though there were no significant differences in the timing of ovulation or the LH surge among the treatment groups, a higher concentration rate was achieved in ewes synchronized with CIDR devices during the second trial. This may reflect an increase in the skill level of the TAI technician.(AU)
Asunto(s)
Estudio Comparativo , 21003 , Masculino , Sincronización del Estro/fisiología , Inseminación Artificial/veterinaria , Ovinos/fisiología , Administración Intravaginal , Dinoprost/fisiología , Hormona Luteinizante/sangre , Ovulación/fisiología , Progesterona/sangre , Progesterona/fisiología , Radioinmunoensayo/veterinaria , Distribución Aleatoria , Clima Tropical , Islas Virgenes de los Estados UnidosRESUMEN
Hair sheep ewes (St. Croix White and Barbados Blackbelly) were used to evaluate 3 methods of estrus synchronization for use with transcervical artificial insemination (TAI). To synchronize estrus, ewes (n = 18) were treated with PGF2alpha (15 mg, im) 10 d apart, with controlled internal drug release (CIDR) devices containing 300 mg progesterone for 12 d (n = 18), or with intravaginal sponges containing 500 mg progesterone for 12 d (n = 18). On the day of the second PGF2alpha injection or at CIDR or sponge removal, sterile rams were placed with the ewes. Jugular blood samples were collected from the ewes at 6-h intervals until the time of ovulation, and daily for 16 d after estrus (Day 0). Plasma was harvested and stored at -20 degrees C until LH, and progesterone concentrations were determined by RIA. There was no difference (P>0.10) in time to estrus among the CIDR-, PGF2alpha- or sponge-treated ewes. All of the ewes in the CIDR group and 94.4% of the sponge treated ewes exhibited estrus by 36 h after ram introduction, while only 72.2% of PGF2alpha-treated ewes showed signs of estrus by this time (P<0.06). The time from ram introduction to ovulation was not different (P>0.10) among the CIDR-, PGF2alpha- or sponge-treated ewes. The time to the preovulatory LH surge was similar (P>0.10) among CIDR, PGF2alpha and sponge treated ewes. Progesterone levels through Day 16 after the synchronized estrus were not different (P>0.10) among treatment groups. Hair sheep ewes (n = 23) were synchronized using PGF2alpha and bred by TAI using frozen-thawed semen 48 h after the second injection. The conception rate to TAI was 2/23 (8.7%) and produced 3 ram lambs. In a subsequent trial, 17 ewes were synchronized with CIDR devices and bred by TAI using frozen-thawed semen 48 h after CIDR removal, resulting in a conception rate of 52.9% (9/17). It is possible to synchronize estrus in hair sheep using either CIDRs, sponges or PGF2alpha. Even though there were no significant differences in the timing of ovulation or the LH surge among the treatment groups, a higher conception rate was achieved in ewes synchronized with CIDR devices during the second trial. This may reflect an increase in the skill level of the TAI technician.
Asunto(s)
Sincronización del Estro/fisiología , Inseminación Artificial/veterinaria , Ovinos/fisiología , Administración Intravaginal , Animales , Dinoprost/fisiología , Femenino , Hormona Luteinizante/sangre , Masculino , Ovulación/fisiología , Progesterona/sangre , Progesterona/fisiología , Radioinmunoensayo/veterinaria , Distribución Aleatoria , Clima Tropical , Islas Virgenes de los Estados UnidosRESUMEN
Two trials were conducted to evaluate the efficacy of oestrous synchronisation procedures in St. Croix White, Barbados Blackbelly hair and Florida Native wool ewes. In Trial 1 (conducted in June), 27 ewes were treated with controlled internal drug release (CIDR) devices for 12 days (CIDR1) and 29 untreated ewes served as controls (CONT). The CIDR devices were removed on the same day that intact rams equipped with marking harnesses were placed with the ewes. Time to oestrus after ram introduction was shorter (P < 0.0001) in CIDR1 than CONT ewes. Within 3 days of ram introduction 100% of CIDR1 ewes but only 37.9% of CONT ewes had been in oestrus (P < 0.0001). Conception rate at first oestrus after ram introduction was 74.1% overall, with no effect (P > 0.10) of treatment, but days to conception were shorter (P < 0.001) in CIDR1 than CONT ewes. Ovulation rate at first oestrus after ram introduction was not different (P > 0.10) between CIDR1 and CONT ewes. The CIDR1 ewes lambed earlier (P < 0.004) in the lambing season than CONT ewes, but there was no difference in the number of lambs born per ewe (P > 0.10). In Trial 2 (conducted in October), 14 St. Croix White ewes were treated with CIDRs as in Trial 1 (CIDR2) and 14 St. Croix White ewes were given two i.m. injections (15 mg) of prostaglandin F2 alpha (PGF) 10 days apart. Intact rams were introduced on the day of CIDR removal or the second PGF injection. The CIDR2 ewes exhibited oestrus earlier (P < 0.01) than PGF treated ewes. The conception rate to breeding at the synchronised oestrus was similar (P > 0.10) between CIDR2 and PGF treated ewes. Progesterone concentration on Day 10 after the synchronised oestrus was not different (P > 0.10) between CIDR2 and PGF treated ewes. These results indicate that oestrous synchronisation procedures can be used in sheep in the tropics without adversely affecting fertility. Due to a lack of seasonal anoestrous these procedures have the potential to be used during all times of the year.