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Two experiments were performed to determine the endocrine and ovarian changes in medroxyprogesterone acetate (MAP)-primed ewes after ram introduction. Experiment 1 was performed during the mid-breeding season with 71 ewes primed with an intravaginal MAP sponge for 12 days. While the control (C) ewes (n = 35) were in permanent contact with rams, the ram effect (RE) ewes (n = 36) were isolated for 34 days prior to contact with rams. At sponge withdrawal, all ewes were joined with eight sexually experienced marking Corriedale rams and estrus was recorded over the next 4 days. The ovaries were observed by laparoscopy 4–6 days after estrus. Four weeks later, pregnancy was determined by transrectal ultrasonography. In eight ewes from each group, ovaries were ultrasonographically scanned; FSH, LH, and estradiol-17β were measured every 12 hours until ovulation or 96 hours after estrus. The response to the rams was not affected by the fact that ewes had been kept or not in close contact with males before teasing. No differences were found in FSH, LH, estradiol-17β concentrations, growth of the ovulatory follicle, onset of estrus, ovulation rate, or pregnancy rate. Experiment 2 was performed with 14 ewes during the nonbreeding season. Ewes were isolated from rams for 1 month, and received a 6-day MAP priming. Ovaries were ultrasonographically scanned every 12 hours, and FSH, LH, estradiol-17β, and progesterone were measured. Ewes that ovulated and came into estrus had higher FSH and estradiol-17β levels before introduction of the rams than did ewes that had a silent ovulation. The endocrine pattern of the induced follicular phase of ewes that came into estrus was more similar to a normal follicular phase, than in ewes that had a silent ovulation. The follicle that finally ovulated tended to emerge earlier and in a more synchronized fashion in those ewes that did come into estrus. All ewes that ovulated had an LH surge and reached higher maximum FSH levels than ewes that did not ovulate, none of which had an LH surge. We conclude that (a) the effect of ram introduction in cyclic ewes treated with MAP may vary depending on the time of the breeding season at which teasing is performed; (b) patterns of FSH, and estradiol-17β concentrations, as indicators of activity of the reproductive axis, may be used to classify depth of anestrus; and (c) the endocrine pattern of the induced follicular phase, which is related to the depth of anestrus, may be reflected in the behavioral responses to MAP priming and the ram effect.

Context: Sus scrofa is a species that easily adapts to diverse environments and climatic zones. In urban and suburban spaces, its presence negatively impacts soil, crops, and animal production, posing health risks for other animals and even humans. Declared a national pest in Uruguay, it is one of the main predators of sheep. A deeper knowledge of its habitat, current distribution, and the environmental factors that influence its locations is required to develop an adequate programme to control its population. Aims: To determine the spatial distribution of wild boars in Uruguay and its association with environmental factors concerning livestock production, on the basis of a survey administered to farmers. Methods: The survey was completed by 2360 farmers, gathering information on the presence of wild boars and other wildlife animals on their farms, methods used for wild boar control, economic damages caused by the species, number of sheep, and types of land-cover besides pastures (native woodlands, shelter forests, pine plantations, and eucalyptus plantations). Key results: Farms located in the Northeast region, with native woodlands and/or pine plantations, and larger than 500 ha were more likely to report the presence of wild boars. The presence of eucalyptus plantations did not affect the presence of wild boars in any region of the country. While the presence of sheep, free- ranging dogs, or wild boars on neighbouring farms affected the presence of wild boars, the existence of eucalyptus plantations showed no effect across any region of the country. On the other hand, the presence of wild boars increased in association with the presence of pampas foxes (Lycalopex gymnocercus). Conclusions: These results provide valuable information regarding the current distribution of an invasive exotic ungulate, and factors influencing the probability of reporting its presence. Implications: This information will serve as a starting point for future research analysing additional ecological and farm characteristics, as well as management strategies in sheep farms aimed at detecting, evading, dissuading and/or controlling this predatory species on the basis of its behaviour and environmental preferences. The wild boar, one of the top 100 most dangerous invasive species, is a major predator of sheep in Uruguay. This study aimed to determine how farm location and environmental factors related to production farms influence the spatial distribution of wild boars. Results showed that farm location and land-cover type affect the probability of wild boar presence. We also provide predictions for potential wild boar presence that can be useful for future management strategies to control this species. Map by Noelia Zambra. [ABSTRACT FROM AUTHOR]

This study aimed to compare the daily variation pattern of testosterone, cortisol, insulin, total blood protein, albumin concentration, glycemia, activity pattern, and surface temperature in 10 Corriedale rams during the breeding (BS) and the non-breeding (NBS) seasons. The surface temperature had a greater mesor but a lower amplitude (P < 0.001), and its' acrophase was later during the BS than during the NBS. The mesor and amplitude of cortisol were lower during the BS than during the NBS (P = 0.01 for both). The acrophase of the time sleeping and the glycemia:insulin ratio occurred earlier during the BS than during the NBS (P = 0.001 in both). During the BS, there was a greater mesor of testosterone, a greater glycemia (P < 0.001), and a tendency to greater insulin (P = 0.06) than during NBS, but without changes in their daily variation pattern between seasons. In conclusion, some daily variation patterns were robust and maintained despite seasonal variations. Other patterns such as the surface temperature, the behavior pattern, cortisol concentration, and glycemia:insulin ratio were more sensitive to the modulation exerted by environmental variations or the internal changes triggered by them, probably because they are directly involved in favoring the seasonal adaptation in rams. [ABSTRACT FROM AUTHOR]

Size and bone mineralization of deer antlers are related to testosterone concentrations, and antler cast is observed after withdrawal of testosterone concentration. Our objectives were to determine if (i) contact with hinds stimulates antler development and increases hard antler period length in pampas deer (Ozotoceros bezoanicus (L., 1758)) and (ii) antlers from males that were or were not in contact with hinds differ in colour. While 5 males were in breeding paddocks consisting of 1 adult stag and 5-10 hinds, the other 6 males were allocated as a single-male group. We collected, weighed, and measured the volume, circumferences, and lengths of antlers, and determined their colour. First antler cast tended to be later in males in contact with females than those in the single-male group. Antler mass and volume were greater in antlers from males in contact with females. Circumference at the base of first and second tines was also greater in antlers collected from males in contact with females. Surfaces of antlers from these males were darker than those of antlers from males that remained isolated from females in all points. Hind contact stimulated male pampas deer, increasing antler mass, size, and darkness, as well as possibly hard antler period length. La taille et la mineralisation osseuse des bois de cerfs est en relation avec les concentrations de testosterone et la chute des bois s'observe apres la reduction des concentrations de testosterone. Nos objectifs sont de determiner (i) si le contact avec les biches stimule le developpement des bois et allonge la periode des bois durs chez le cerf des pampas (Ozotoceros bezoarcticus (L., 1758)) et (ii) si la couleur des bois des males en contact avec les biches differe de celle des males sans contact. Alors que 5 males se trouvaient dans des enclos de reproduction contenant chacun 1 cerf adulte et 5-10 biches, les autres 6 males formaient un seul groupe exclusif de males. Nous avons recolte, pese, mesure le volume, les circonferences et les longueurs des bois et determine leur couleur. La premiere chute des bois a tendance a se faire plus tardivement chez les males en contact avec des femelles que chez ceux qui font partie du groupe exclusif de males. Les bois des males en contact avec les femelles ont une masse et un volume plus importants. La circonference au niveau du premier et du second andouiller est aussi plus grande dans les ramures des males en contact avec les femelles. Les surfaces des bois de ces males sont plus foncees que celles des males qui ont ete constamment isoles des femelles. Le contact avec les biches stimule les cerfs des pampas, augmente la masse, la taille et la coloration foncee des bois et prolonge peut-etre la duree des bois durs. [Traduit par la Redaction], Introduction Reproductive processes are consequence of external environmental signals and endogenous mechanisms of neuroendocrine regulation. Socio-sexual signals interact with the neuroendocrine system and with other external signals stimulating or inhibiting [...]

Context: In extensive grazing sheep systems, pregnant ewes undergo periods of undernutrition because gestation coincides with winter when natural pasture is of lowest quantity and poorest quality. The lamb's weight and thermoregulatory capacity, and the ewe–lamb bond at birth, may be compromised. Maternal melatonin treatment during gestation may reverse these effects. Aim: The aim was to determine the effects of melatonin treatment of single-lambing, undernourished ewes during the last third of gestation on lamb birthweights and body temperatures, and on ewe–lamb interactive behaviour after birth. Methods: At Day 100 of gestation, 39 single-bearing ewes received a subcutaneous melatonin implant, and 54 ewes served as controls with no implant. Throughout gestation, the ewes remained under extensive conditions grazing on natural pasture. Measurements were made of lamb birthweight, body temperatures (surface temperature by infrared thermography and rectal temperature), and ewe–lamb behaviours during a handling test at 6–17 h after lambing. Key results: There was no effect of melatonin treatment on lamb birthweight or rectal temperature, or on ewe–lamb interaction behaviours. Hip minimum surface temperature was greater in lambs from melatonin-treated ewes than lambs from control ewes (21.2°C ± 0.9°C vs 18.8°C ± 0.8°C; P = 0.05), and there was a similar trend for hip mean surface temperature (24.6°C ± 0.9°C vs 22.3°C ± 0.7°C; P = 0.06). Rump surface temperatures were greater in male than female lambs: maximum (27.9°C ± 1.2°C vs 22.9°C ± 1.2°C; P = 0.01), minimum (22.2°C ± 1.5°C vs 16.7°C ± 1.5°C; P = 0.02) and mean (25.4°C ± 1.3°C vs 20.5°C ± 1.3°C; P = 0.02). Conclusion: Melatonin treatment during the last third of ewe pregnancy slightly enhanced the surface temperature of lambs at birth but did not influence ewe–lamb interaction behaviour after birth (i.e. after establishment of the ewe–lamb bond). Implications: Further study in more depth is warranted into the possible effects of maternal supplementation with commercial melatonin implants on lamb development, thermoregulatory capacity, behaviour and survival rates in extensive grazing systems, including the effect on ewe–lamb behaviours immediately after birth for both singletons and twins. In sheep extensive production systems, pasture availability decreases in winter; thus, ewes are undernourished during gestation. Maternal melatonin treatment could mitigate intrauterine growth restriction induced by maternal undernutrition, enhancing bodyweight at birth and body temperature of lambs, and improving ewe–lamb behaviours at birth. In this study, only lamb hip surface temperature was enhanced after birth, whereas ewe–lamb interactions, lamb birthweight and rectal temperature were unaffected by melatonin treatment. [ABSTRACT FROM AUTHOR]