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Most donkey and local horse breeds are vulnerable to extinction as mechanization of agriculture progress throughout the world. The present study analyzed the pedigree and herd records of the donkey Asinina de Miranda breed (RAM), identifying genealogical and human factors that may affect the breed genetic diversity in the future and suggesting suitable strategies to breed preservation, early on the conservation program. The breeding rate was very low, with a ratio of foaling/live animals of 0.23 (178/760). The estimated number of founders and ancestors contributing to the reference population was 128 and 121. The number of founder herds in the reference population was 64, with an effective number of founder herds for the reference population of 7.6. The mean age of herd owners was 65.50 ± 0.884 years, with a negative association among the herd size and owner's age ( P < 0.001). In contrast, the size of the herd and the ownership of a male were both positively associated ( P < 0.001) with the herd number of in-born foals. Both the owners' age and the herd location (RAM home region v. dispersal region) were negatively associated with the foaling number ( P < 0.001). The main identified risk factors were: low breeding rates; low number of males and their unequal contribution to the genetic pool; unequal contribution of the herds to genetic pool; and advanced age of herd owners.

A case of disrupted embryonic development of the genital tract in a newborn Holstein calf is described. The physical examination of the calf evidenced several abnormalities, like atresia ani, rudimentary external genitalia and caudal vertebral agenesis. On necropsy, the excised genitalia consisted of bilateral streak gonads, apparently normal uterine tubes, a fluid-filled uterus, a long vagina and a very narrow clitoris-like structure covered with a discrete skin-fold. The urinary tract seemed normal and the urethra's opening was at the vestibule-vaginal junction. A cytogenetic analysis was requested. Karyotype revealed the existence of Y chromosome material in the two X chromosomes. However, the search for the sex-determining region Y (SRY) showed that this was an apparently absent gene. The histological examination of the gonads revealed the existence of ovarian dysplasia. Uterine sections evidenced the absence of the uterine epithelium, with only sporadic caruncles. Under microscopic examination, the uterine tubes and vagina structure was normal. The external genitalia sections revealed the existence of a skin-fold covering an erectile structure surrounding the urethra, a structure more similar to a penis than to a clitoris. This is an unusual situation of gonadal dysplasia combined with genital tract anomalies in cattle, probably associated to a genetic defect.

This study aims to characterize the estrous cycle of Asinina de Miranda jennies in the breeding season, on the basis of data collected from serial ultrasonographic examination and serum progesterone determinations in 14 females during a total of 33 cycles. The length of the interovulatory interval was 23.8 ± 0.55 days, the diestrus and estrus lasting 17.9 ± 0.46 days and 6.65 ± 0.30 days, respectively. Age and body condition score (BCS) affected the length of the interovulatory intervals; BCS also influenced the diestrus length and the time in heat after ovulation (P > 0.05). The incidence of single, double, and triple ovulations was 57.58%, 36.36%, and 6.06%, respectively. Multiple ovulations affected neither the length of the interovulatory interval nor the individual cycle stages (P > 0.05) but lengthened the interval from the beginning of estrus to the last ovulation (P = 0.01). When combined with age, higher BCS affected the ovulation rate (P = 0.001). Deviation of the dominant follicle occurred around Day 8.7 (Day 0 = ovulation) when both single and multiple ovulations were considered. The dominant follicle was larger at divergence in single ovulators (19.18 ± 0.97 mm) compared with that in multiple ovulators (18.05 ± 1.16 mm). The overall maximum follicular diameter before ovulation was smaller in multiple ovulatory cycles than that in single ovulatory cycles (37.2 ± 0.83 mm vs. 40.2 ± 1.41 mm, respectively; P = 0.03). The daily growth rate of dominant follicles was independent of the ovulation rate (P > 0.05) for the intervals before and after the estrus onset. The dominant follicle size and the follicle growth rates were independent of BCS (P > 0.05). Data collected in this study revealed resemblances between Mirandese and other Iberian and Brazilian breeds with regard to estrous cycle characteristics.

BackgroundIn equids, health and welfare depend on body composition. A growing number of equids are now used as leisure and companion animals, and often found overfeed. The need for a close monitoring of body fatness led to the search for tools allowing a rapid and non-invasive estimation of fatness. This study intends to assess real-time ultrasonography (RTU) usefulness in establishing a relationship between ultrasound measures of subcutaneous fat–plus–skin thickness (SF-Skin) and body condition score (BCS) in horses and donkeys. Forty-three healthy animals (16 donkeys and 27 horses) were used in this study to generate 95 records (RTU and BCS pairs), in multiple RTU sessions for 2 years. Using visual appraisal and palpation, BCS was graded in a 1–9 points scale. Real-time ultrasonography images were taken using a 7.5 MHz linear transducer, placed perpendicular to the backbone, over the 3rd lumbar vertebra. ImageJ was used to measure the SF-Skin on RTU images. The relation between BCS and SF-Skin measurements was tested by linear and polynomial regression analysis.ResultsThe BCS values were similar in horses (5.50; from 3 to 8 points) and donkeys (5.14; from 3 to 7 points). The SF-Skin measures show a similar trend (a mean of 7.1 and 7.7 mm in horses and donkeys, respectively). A polynomial regression among BCS and SF-Skin explained 92 and 77 % of the variation in donkeys and horses respectively. The coefficient of determination was considerably higher for the regression developed for donkeys compared with that of horses (R2 = 0.92 vs. 0.77, respectively), which reduced the accuracy of the method in horses. Both the linear and polynomial models tested show a strong relationship among BCS and SF-Skin for donkeys (R2 > 0.91; P < 0.01) and horses (R2 > 0.74; P < 0.01), despite that the extremes for BCS did not existed in our sample.ConclusionsOur results showed the potential RTU usefulness to monitor body fat in equids. Using a high-frequency transducer and RTU together with image analysis allowed the identification of small SF-skin variations. This report will support further studies on the relationships between SF-Skin and BCS, particularly in extreme BCS scores.