This study investigates the effect of time of storage of epididymides at room temperature and the addition of 20% of seminal plasma to the cryopreservation extender, on post thaw quality and fertility of ovine spermatozoa collected from the cauda epididymis. Spermatic kinetics, integrity and the stability of plasma membrane, damage to the acrosome and fertility following laparoscopic artificial insemination were evaluated in samples collected in an artificial vagina (AV) and from epididymides stored at room temperature for zero (G0), six (G6), twelve (G12), twenty-four (G24) and forty-eight (G48) hours post mortem. There were no significant differences in spermatic parameters between the methods of sample collection, except for progressive motility and velocity according to the straight path(VSL). G48 samples had significant lower total motility(TM), progressive motility(PM), kinetic parameters, viability and acrosomal integrity. Pregnancy rate after insemination was similar for samples collected using AV, and the G0, G6, G12 and G24 samples. In conclusion, ovine epididymides can be exposed to room temperature, for up to 24 h post mortem, with no effect on viability and fertility of cryopreserved seminal samples. The addition of seminal plasma to the cryopreservation extender had no effect on spermatozoa quality nor fertility.

Contents Multiple ovulation and embryo transfer (MOET) is an important tool in the sheep industry for increasing numbers of genetically superior individuals. The objective of this study was to evaluate the effect of semen source (frozen or fresh), the number of embryo collection procedures for each donor (NECP), the season in which embryo transfer and collection was performed, and the age and breed of the donor, on the number of recovered embryos and pregnancy rates after embryo transfer. The Alamos Genetics’ flushing station database was used. This consisted of 140 embryo collection procedures, from 53 Dorper and White Dorper sheep donors, aged between one and eight years, totalling 1,200 collected embryos. Neither the number of retrieved embryos nor the pregnancy rate was affected by the semen preservation method (fresh or frozen), NECP or the age and breed of donor. The season did not affect the number of collected embryos but had a significant effect (p < 0.05) on the recipient pregnancy rate, with higher pregnancy rates reported in the winter (65.57% ± 25.33%) compared with spring (37.11% ± 33.27%), summer (29.95% ± 28.33%) or autumn (35.03% ± 31.66%). There is an estimated increase of 98.4% and 71.5% of embryos recovered in the spring and summer seasons, respectively, when winter is used as reference. The survival of embryos is significantly higher when implanted during the breeding season, more specifically in winter. Embryo collection can be carried out throughout the year in sheep, but there may be a marginal advantage in the use of superovulation and fresh embryo transfer programmes in the autumn and winter.

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Summary: To achieve the desired reproduction rate of one foal per year per mare and to optimize the reproductive potential of mares that are embryo donors, foal heat should be utilized as a tool for improvement of fertility. The mare is the only domestic animal showing ovulatory estrus shortly after foaling. The uterine involution and the ovarian activity (post partum follicular dynamic) in the early puerperium go through brief periods of time. Fetal expulsion at physiological delivery occurs within a short time and the placenta is expelled few hours later. Such events in the intra-and peri-partal period may be also related to the type of histological tissue that composes the cervix in these animals. The mare's cervix (muscular type) has a fantastic speed related to uterine involution, unlike the other species in domestic animals (cervix fibro-cartilaginous type) (more resistant requesting more time to involute). Nonetheless, fertility during foal heat is reported to be by some authors better or similar or even lower than fertility during heat outside this period. There are still some controversies on this matter, so we hypothesized that non-lactating mares have a greater potential for pregnancy rate than that lactating mares in foal heat, because the uterine involution is already finalized and ovarian activity is basically normalized in non-lactating mares, opening greater possibilities to became pregnant. In Southern Brazil, the Criollo breed (an original cross between Andalusian and Berber breeds) is a well stablished and widely used breed of horse, as it adapted well to the features of the Brazilian climate under field conditions, and developed two useful abilities (too much for work, and sports). To improve the reproduction mainly in Criollo horses, this study aimed to compare the pregnancy rate (PR) and other reproductive parameters (parturition-artificial insemination interval; parturition-ovulation interval; diameter of preovulatory follicle; artificial insemination-ovulation interval) between lactating mares in early puerperium and non-lactating mares artificially inseminated (AI) ≥ 180 days postpartum. This study took place at a stud farm in Southern Brazil between September and December (breeding season). Thirty-one mares Criollo breed, multiparous with mean age 9.6 years (range 6 -14) and body condition score (BCS) 3.1 (1= thin, 5 = obese) were divided into two groups: lactating mares (LMs) subjected to AI <10 days postpartum (n =16) and non-lactating mares (NLMs) AI ≥180 days postpartum (n =15). The mares were selected based on clinical criteria (absence of clinical endometritis or abnormal uterine discharge and by parturition date). Both groups had the same environment and nutritional conditions. The ovaries were examined by ultrasonography every other day; after detection of a follicle ≥ 30 mm in diameter (= the sum of the larger and smaller diameter divided by 2), the examinations with ultrasonography were conducted daily. After the detection of follicles ≥ 35 mm, uterine edema, and open cervix, ...

Contents The study aimed to evaluate pregnancy per artificial insemination (P/AI) of cows subjected to synchronization and resynchronization in ovulation protocols using intravaginal progesterone‐releasing insert (P4) before pregnancy diagnosis (PD) and the relationship of PR with the diameter of preovulatory follicles (ØPOF) before TAI. Cows (n = 378) were distributed into two groups: a resynchronization group with new devices (GRN; n = 185) and resynchronization group with used devices (GRU; n = 193). On Day 0, both groups received a new P4 and estradiol benzoate (EB). On D8, P4 removal + D‐cloprostenol + eCG + estradiol cypionate (EC) was done. On d10, TAI was conducted. On d32, cows were resynchronized and divided into two groups, GRN (n = 185) and GRU (n = 193). The GRN group received a new P4 + EB, and the GRU group received a used P4 + EB. On d40, the P4 was removed + PD. The non‐pregnant cows received D‐cloprostenol + eCG + EC. US was done again on d42 to determine ØPOF before the second TAI. The P/AI of the GRN and GRU groups after synchronization were 56.2% and 57.0% (p = 0.87), respectively, and those after resynchronization were 58.0% and 37.3% (p < 0.008), respectively. The P/AI of the GRN and GRU groups observed after TAI (synchronization + resynchronization) were 81.6% and 73.1%, respectively (p = 0.047). No difference (p = 0.067) in ØPOF between the pregnant and non‐pregnant cows in the GRN was found, whereas the GRU group showed a significant difference (p = 0.003). Resynchronization protocols optimized the P/AI in both groups. New intravaginal devices resulted in greater P/AI and P/AI accumulation in resynchronization as compared with the GRU; the ØPOF was related with P/AI.