Umberto Tosi

Oxytocin, vasopressin, prostaglandin F2α, luteinizing hormone, testosterone, estrone sulfate, and cortisol plasma concentrations after sexual stimulation in stallions

This experiment was designed to determine the effects of sexual stimulation on plasma concentrations of oxytocin (OT), vasopressin (VP), 15-ketodihydro-PGF(2alpha) (PG-metabolite), luteinizing hormone (LH), testosterone (T), estrone sulfate (ES), and cortisol (C) in stallions. Semen samples were collected from 14 light horse stallions (Equus caballus) of proven fertility using a Missouri model artificial vagina. Blood samples were collected at 15, 12, 9, 6, and 3 min before estrous mare exposure, at erection, at ejaculation, and at 3, 6, and 9 min after ejaculation. Afterwards, blood sampling was performed every 10 min for the following 60 min. Sexual activity determined an increase in plasma concentrations of OT, VP, C, PG-metabolite, and ES and caused no changes in LH and T concentrations. The finding of a negative correlation between C and VP at erection, and between C and T before erection and at the time of erection, could be explained by a possible inhibitory role exerted by C in the mechanism of sexual arousal described for men.

Electrolytes changes in mammary secretions before foaling in jennies

No knowledge regarding the peripartum changes in mammary secretions in the jenny are presently available in literature. In the mare, instead, several studies report the role of these changes as indicators of foetal readiness for birth and impending parturition. This experiment was designed to determine calcium, sodium, potassium concentrations, and the value of sodium/potassium ratio in mammary fluids during prepartum in the jenny. Samples were daily collected by hand milking, after mammary gland size increased noticeably, from 17 Martina Franca jennies. Prepartum mammary secretions were analysed every other day between day 10 and day 2 antepartum, and then once a day from the day before to the day of parturition. Calcium concentration showed a significant increase between day 10 and day 6 antepartum and then between day 6 and days 4 and 2. Afterwards, another statistical significant increase was observed at parturition. Sodium concentration significantly decreased from day 10 to day 2 prepartum. Potassium concentration significantly increased between day 10 and day 8 before parturition, then showed a further increase at day 4, followed by none significant changes until foaling. All jennies showed a reversal in sodium/potassium ratio between 2 days antepartum and the day before. In conclusion, the evaluation of mammary fluid calcium concentrations and the reversal of sodium/potassium ratio could be used as good indicators of foetal maturity in the jenny. As far as the prediction of parturition is concerned, the reversal of sodium/potassium ratio is the best parameter, since it was detected 48-24 h before parturition in all considered animals.

Luteal function in jennies following PGF2α treatment 3 days after ovulation

Native PGF(2alpha) and its analogs have been used in the horse mare to manipulate ovarian activity, primarily as luteolytic agents to induce estrus. Despite numerous studies on the effects of these luteolysins in the mare, to date only a single investigation has been conducted in the jenny. The aim of this study was to evaluate the response of the corpus luteum (CL) to a single dose of PGF(2alpha) given 3 days (72h) after ovulation and to establish the plasma progesterone (P4) profile from pre-treatment to post-treatment ovulation in the Martina Franca donkey. Twenty-two jennies were ultrasonographically monitored and treated 72h after the detection of ovulation with 0.075 mg i.m. of R-cloprostenol. From the day of ovulation until ovulation post-treatment, blood was collected daily for P4 determination by enhanced luminescence immunoassay. All the jennies except one, exhibited behavioral signs of PGF(2alpha)-induced estrus within 4 days of treatment lasting 5.4+/-1.16 days. Post-treatment ovulation was also hastened, reducing the interovulatory interval (9.6 days). In response to treatment, plasma P4 concentrations fell to estrus levels and then remained constant until the next ovulation in all but the non-responding animal. Our findings indicate that PGF(2alpha) treatment on Day 3 post-ovulation causes the functional regression of the CL in the jenny, reflected both by the rapid induction of estrus and ovulation and by an abrupt drop in circulating P4 concentrations.

Morphological features of the placenta at term in the Martina Franca donkey

This study was designed to establish the morphological features of the placenta of the Martina Franca jenny. Ten placentas were harvested at the time of foal delivery and examined both for gross and histological characteristics. The following factors were determined: the total weight and volume of the placenta and its components, the surface area of the allantochorion, umbilical cord length and site of insertion, and the diameter of the umbilical cord vessels and vascular pattern type. The weight of the placenta was similar to previously reported for ponies, and represented 12% of foal birth weight. Umbilical cord length was similar to that in the horse but longer than in the pony, while cord weight was intermediate between the two. In a histological examination, numerous strong villi were observed at sites corresponding to the non-pregnant and pregnant horn and uterine body. No villi were detected in the area overlying the cervical star. Despite obvious similarities between the donkey and horse placenta, specific morphological features do exist, and are possibly related to the differences in length of gestation.

Postpartum reproductive activities and gestation length in Martina Franca jennies, an endangered Italian donkey breed

The donkey reproductive physiology is still partially known despite the increasing risk of extinction involving several breeds. The present study was designed to describe the postpartum (PP) reproductive performance of an Italian endangered breed: the Martina Franca donkey. To this aim, 52 jennies were monitored to define the foal-heat (FH) and the first and second PP estrus episodes (1st PPe and 2nd PPe). The data indicate that jennies spontaneously recovered reproduction in approximately 10 days after delivery. Then heats occur with a regular interval of approximately 23 days. Estrus length was 1 week in FH and the 2nd PPe and significantly shorter in the 1st PPe. Estrus-ovulation, and delivery-ovulation interval and follicle growth were similar in all animals tested. Pregnancy rate (PR) was lower when natural mating occurred during the FH and 2nd PPe (approximately 60%) than during the 1st PPe (approximately 70%; P < 0.01). In addition, the higher PR (>80%; P < 0.01) was recorded in jennies when the FH occurred after the first week PP and it dropped (<50%) in early FH animals. The PR was also affected by the season and by age: it significantly declined during the autumn-winter season and in subjects older than the sixth year of age. For the first time, the reproductive performance of PP donkeys were defined on a large number of Martina Franca jennies thus offering useful information to improve farm management with an immediate benefit to increase livestock production. This aspect of management improvement might be particularly important if applied to an endangered breed such as Martina Franca donkeys.

Corpus Luteum Sensitivity to PGF2α Administration in the Martina Franca Jenny

A. Carluccio1,∗, U. Tosi1, A. Contri1, I. De Amicis1 and M.C. Veronesi2 1Department of Veterinary Clinical Sciences, Division of Obstetrics-Gynaecology and Animal Reproduction, Faculty of Veterinary Medicine, University of Teramo, 64020, Teramo, Italy; 2Department of Veterinary Clinical Sciences, Division of Obstetrical and Gynaecological Clinics, Faculty of Veterinary Medicine, University of Milan, 20133, Milan, Italy ∗Correspondence: E-mail: carluccio@unite.it

Ultrasonographic evaluation of sexual glands before and after ejaculation in the jackass

Ultrasonographic evaluation of sexual glands before and after ejaculation in the jackass A. Contri & U. Tosi & I. De Amicis & M. C. Veronesi & S. Panzani & A. Carluccio Published online: 7 August 2008 # Springer Science + Business Media B.V. 2008