The pFSH dose affects the efficiency of in vivo embryo production in Santa Inês ewes.

This study compared the follicular growth, superovulatory response, and in vivo embryo production after administering two doses of porcine follicle-stimulating hormone (pFSH) in Santa Inês ewes. The estrous cycle of 36 multiparous ewes was synchronized with the Day 0 protocol and superovulated with 133 mg (G133, n=18) or 200 mg (G200, n=18) of pFSH. Ultrasonographic evaluations of the ovaries were performed, ewes were mated and submitted to non-surgical embryo recovery. Viable blastocysts were stained with Nile Red and Hoechst. The G200 had a greater number of medium and large follicles, as well as a larger size of the third largest follicle. A total of 97.2% (35/36) of the ewes came into estrus and it was possible to transpose cervix in 80.6% (29/36). There were no effects of treatments in the response to superovulation, the proportion of ewes in which was possible to transpose the cervix, the number of corpora lutea, the number of anovulatory follicles, the proportion of ewes flushed with at least one recovered structure, number of recovered structures, number of viable embryos, viability rate, and recovery rate. The G200 ewes were in estrus for a longer period of time than the G133 ewes (54.0 ± 4.5 h vs. 40.3 ± 3.6 h) and produced more freezable embryos (6.5 ± 1.6 vs. 2.3 ± 0.7) than G133. Both doses promoted an efficient superovulatory response and did not affect embryonic lipid accumulation. The dose of 200 mg of pFSH showed greater potential to increase the superovulatory response, as it increased follicular recruitment and the recovery of freezable embryos.

Social Stress during the Estrus or Luteal Phase in Sheep.

In mammals, progesterone and estrogens affect the stress response. The study aimed to compare the physiological and behavioral responses to the social isolation of ewes during the estrus or luteal phase. Estrous and diestrous ewes (n = 10 and 8 respectively) were individually isolated in a novel place for 10 min. Ewes' behavior was recorded during the test. Cortisol, blood proteins and glucose concentrations, and the skin surface temperature were determined before and after the test. Cortisol increased immediately after the test ended (P = 0.02). Serum total protein (P = 0.02), globulin (P < 0.0001), and plasma glucose (P = 0.006) concentrations were greater in estrus than in the luteal phase. The abdominal skin surface temperature was greater during estrus than during the luteal phase (P = 0.02). Ewes in estrus spent more time standing up immobile than ewes in the luteal phase (P = 0.05). In conclusion, the physiological and behavioral responses changed according to the phase of the estrous cycle. These results highlight the need for future studies focusing on how reproductive status influences the stress response to different management practices in sheep.

The association of resveratrol and AFPI did not enhance the cryoresistance of ram sperm.

Cryoprotectants are required to reduce damage caused to the cells due to low temperatures during the cryopreservation. Antifreeze proteins (AFP) have a well-known role in cell membrane protection, while resveratrol is a potent antioxidant. This study assessed the effect of the association of resveratrol concentrations and AFP I in a ram semen extender. Pooled semen of four rams was allocated into six treatments in a factorial arrangement: (CONT, only the semen extender); only AFP I (ANT: 0.1 µg/mL of AFP I), only resveratrol, one treatment with two levels (10 µM/mL or 50 µM/mL of resveratrol); and two treatments with the interactions, with one AFP I and one of the two levels of resveratrol (0.1 µg/mL of AFP I with 10 µM/mL resveratrol; 0.1 µg/mL of AFP I with 50 µM/mL resveratrol). No interaction between factors was observed on sperm kinetics, plasma membrane integrity, hypo-osmotic test, and mitochondrial activity parameters. There was a high probability (P = 0.06) of reducing sperm cells with functional membrane percentage in the hypo-osmotic test and increasing the percentage of sperm with high mitochondrial activity (P = 0.07) was observed in AFP presence. An interaction of AFP and resveratrol was observed in non-capacitated sperm (P = 0.009), acrosomal reaction (P = 0.034), and sperm binding (P = 0.04). In conclusion, the association of resveratrol and AFP did not improve the quality of frozen-thawed semen and even promoted deleterious effects compared to their single addition in the semen extender. The supplementation of 50 µM/mL of resveratrol improved the outcomes of frozen-thawed ram sperm, being a potential cryoprotectant.

Reproductive seasonality of hair rams under tropical conditions: an alternative for non-seasonal lamb production?

Reproductive seasonality limits the periods of breeding on the year and, therefore, productive output. However, some breeds appear as probably non-seasonal. The aim of the study was to characterize the seasonal pattern of Santa Inês rams, including an ultrasound characterization of the reproductive tract, testosterone concentrations, and semen characteristics. Fifteen Santa Inês rams remained in a grazing system with concentrate supplementation, and measurements of the reproductive tract and ultrasound evaluation (biometrics and pixel intensity) of the testicles and accessory sex glands were monthly recorded. Computerized seminal evaluations were also performed monthly, and serum testosterone concentration was measured every 15 days. Body weight and condition remained stable throughout the year. In general, reproductive traits varied along the year and reached maximum values during autumn and minimum in spring. Despite that, as fresh semen remained with enough quality to breed all along the year, seasonality does not appear as a limiting factor to breed along the year. Therefore, Santa Inês rams can be used for all-year-round breeding or for crossbreeding when rams from other breeds decrease their fertilizing ability.

Semen collection and ejaculation trigger changes in the blood flow of the reproductive system in rams.

The aim of this study was to determine if ejaculation modifies the testicular and accessory sex glands' blood flow after ejaculation, and if those changes differ according to the process that leads to ejaculation. Twelve adult Corriedale rams were used and assigned at random to the four procedures that lead to ejaculation: (G1) electroejaculation; (G2) artificial vagina; (G3) transrectal ultrasound-guided massage of the accessory sex glands; (G4) natural mating. Hemodynamic characteristics evaluation of the male reproductive system was conducted immediately before and at 30 and 90 min after ejaculation. The internal iliac artery peak systolic velocity (PSV) decreased (P=0.01) and supratesticular artery PSV increased (P=0.042) 90 min after ejaculation in all groups. In conclusion, ejaculation modifies the reproductive system's blood flow, with slight variations depending on the studied ejaculation methods. Additionally, ejaculation altered the internal iliac and supratesticular arteries PSV, and the supratesticular artery end-diastolic velocity (EDV) in rams. The supratesticular artery PSV was the only studied variable that differed according to the procedure that triggered the ejaculation.

Sexual stimulation of captive Iberian ibex bucks (Capra pyrenaica): Effect of male social rank on the response to estrous females.

The aims were to determine if the contact with estrous females stimulates testosterone and cortisol secretion in Iberian ibex bucks during or out of the breeding season and if their social rank affects this response. Nine Iberian ibex bucks (Capra pyrenaica), were challenged with estrous does during two periods: winter-spring and autumn (three tests at each season, separated 10 days). Individual success index (SI) was calculated in both season. Bucks were exposed to an estrous doe, their sexual and agonistic behavior was recorded, testosterone and cortisol concentrations were measured. There were no sexual interactions toward the estrous doe in any test. Testosterone concentration was unrelated to the SI in any season and was not modified with the tests. Cortisol concentration was greater in the first than in the second and third tests in both seasons (winter-spring: 99.7 ± 15.7 ng/mL, 65.9 ± 9.4 ng/mL and 62.3 ± 10.1 ng/mL P < 0.0001; autumn: 110.1 ± 15.8 ng/mL, 79.2 ± 13.4 ng/mL, and 87.6 ± 13.5 ng/mL; P < 0.01). Iberian ibex bucks allocated in captivity did not display sexual behaviors nor modify the testosterone secretion, which was not modified by social hierarchy, after estrous doe exposition, during or out of the pre-rutting period.

Use of meloxicam with or without dipyrone in non-surgical embryo recovery in hair sheep: Effects on animal welfare.

The aim of this study was to determine the effectiveness of meloxicam with or without dipyrone on the welfare of ewes subjected to non-surgical embryo recovery (NSER). Two studies were carried out using 51 multiparous Santa Inês ewes. All animals received a standard oestrous synchronization treatment and a superovulatory protocol. In Study 1, 12 ewes received meloxicam (GM) before cervical transposition (1 mg kg-1 , i.v.), repeated 24 h after (1 mg kg-1 , i.m.), while the other 10 received a saline solution, remaining as a control group (GC1). In Study 2, ewes were allocated into a group of 15 ewes treated as GM of Study 1 associated with dipyrone (GMD; 50 mg kg-1 , i.m.) before cervical transposition, 12 h, and 24 h after, or a control group (GC2) of 14 ewes treated with saline solution. In both studies, heart and respiratory rates (RR), cortisol, glucose, total proteins, albumin and globulins blood concentration were recorded before sedation (BS), after sedation (AS), after cervical transposition, immediately after collection (IAC), and 0.5, 1.5, 3, 6, 12, 24 and 48 h after embryo collection (hAC). In Study 1, RR tended to be greater in GC1 (p = .08), serum total proteins and globulins values were lower and serum albumin values were greater in this group than GM (p = .003, p < .0001, and p < .0001, respectively). In Study 2, treatment of GMD tended to reduce the glycaemia at AS (p = .052) and reduced it at 3hAC (p < .0001), and 6hAC (p = .03). It also tended to reduce cortisol concentrations (p = .10). The other variables varied with NSER without interaction with the experimental treatments. In conclusion, in this study condition, NSER in sheep induced transient changes indicative of stress and possibly pain, therefore, affecting animal welfare. The administration of meloxicam was ineffective to reduce those responses, and the association of dipyrone had only slight effects without modifying the main welfare indicative responses in ewes subjected to NSER.

Recent advances in treatments for resynchronization of ovulation in small ruminants: a review.

Hormonal methodologies to control small ruminants' estrous cycle are worldwide used and evolved, adjusting the application to the precise female physiological moments to enhance reproductive performance. The estrous cycle can be induced and/or synchronized, aiming for fixed-time artificial insemination, or based on estrus behavior signs for insemination, natural or guided mating. Successive protocols can be performed to resynchronize ovulation and increase reproductive outcomes in females that failed to conceive. These recently developed treatments aim to resynchronize the ovulation as earlier as non-pregnancy is detected. The present review aimed to summarize the recent advances and main findings regarding resynchronization protocols used in small ruminants. Lastly, we present future perspectives and new paths to be studied in the subject. The resynchronization treatment is still a growing field in small ruminant reproduction, nevertheless, some enhancements are found in the reproductive outcome, showing that such protocols can be successfully used in sheep and goat production.

Rams' reproductive status during a controlled breeding period: effect of social dominance.

The aim of this study was to compare the variation in body weight, scrotal circumference (SC), and seminal quality during a breeding period in dominant and subordinate rams. Data were collected from 12 dyads of rams, each bred with 15 ewes for 7 weeks. Before joining, the dominance relationship between both rams from each dyad was determined. Body weight and SC were recorded weekly in the morning, and semen was collected by electroejaculation, determining the volume, sperm concentration, mass motility, and percentage of sperm with progressive motility. In addition, the total number of sperm and sperm with progressive motility ejaculated were calculated. Dominance had no direct effect or interaction with time on any of the variables analyzed. Body weight, seminal volume, sperm concentration, mass motility, percentage of sperm with progressive motility, and total ejaculated sperm varied with time (p < 0.05), and scrotal circumference and total ejaculated sperm with progressive motility tended to vary with time. In general, all indicators evaluated were affected in the first weeks, when most ewes were cycling, recovering as the breeding progressed. It was concluded that, at least under the conditions of this study, dominance position did not affect the profile of the reproductive variables evaluated, although all of them were affected during the breeding period.

Time of day modified the time required for semen collection with electroejaculation and slightly affected the quality of fresh semen in rams.

The aim was to compare some stress responses to electroejaculation (EE), and the quality of fresh semen, when ram semen is collected at dawn (06:00 h), noon (12:00 h), or evening (18:00 h). Twelve Corriedale rams were used, and semen was collected from four rams at each study time on three different days, with a Latin-square design. The time required for EE, the number of vocalizations emitted, heart rate, and rectal temperature were recorded, and fresh semen was evaluated. The time required for EE was shorter at evening than at dawn and noon (399.3 s, 480.6 s, and 460.2 s respectively; pooled SEM = 72.1; P = 0.03). The percentage of sperm with progressive motility was greater at noon than dawn (59.7% and 50.3%; pooled SEM = 5.8; P = 0.05). Curvilinear velocity was greater at dawn than evening (117.0 µm/s and 95.5 µm/s; pooled SEM = 7.1; P = 0.04), slow linear velocity was greater at evening than at dawn and noon (13.1 µm/s, 9.3 µm/s, and 8.5 µm/s respectively; pooled SEM = 1.7, P = 0.05), and the slow average path velocity was greater at evening than dawn and noon (16.2 µm/s, 11.7 µm/s, and 10.8 µm/s respectively; pooled SEM = 1.9, P = 0.05). In conclusion, the collection time modified the time required for electroejaculation and had only slight effects on the quality of fresh semen. Overall, the time of the day appears to have only slight effects on semen collection and quality.

Thermoregulatory, metabolic and stress responses to spring shearing of aged ewes born to undernourished mothers.

Maternal undernutrition during gestation affects the behaviour, metabolism, and sensitivity to stressors of the offspring. Shearing is a stressor that triggers physiological and behavioural changes and augments the thermoregulatory demands in sheep. The aim of this study was to compare the thermoregulatory, metabolic, and behavioural responses to spring shearing of aged ewes born to mothers who grazed different pasture allowances during gestation. Nineteen non-gestating six-year-old Corriedale ewes born to mothers who grazed two pasture allowances from 23 days before conception until 122 days of gestation were used. The pasture allowance offered to the mothers was high [HPA group; n = 11; 10-12 kg of dry matter (DM)/100 kg of body weight (BW)/day] or low [LPA group: n = 8; 5-8 kg of DM/100 kg of BW/day]. The adult offspring of both experimental groups were sheared during spring (Day 0), and remained outdoors, grazing natural grassland, and the behaviour, the surface temperature and the rectal temperature were recorded. Blood concentrations of albumin, total protein, glucose, and insulin were also determined. Data were compared with a mixed model. The LPA ewes had lower ear and nose maximum and minimum surface temperatures before shearing (P < 0.05). On Day 15, the average surface temperature of the vulva was lower in LPA than in HPA ewes (P < 0.05). After shearing, rumination frequency was greater in HPA than in LPA ewes (P = 0.01), and LPA ewes were observed more time standing up than HPA ewes (P < 0.0001). Insulin concentration tended to be greater in LPA than HPA ewes (P = 0.06). Maternal undernutrition during gestation modified the thermoregulatory responses and the acute behavioural changes after shearing in aged female offspring, whilst the metabolism was affected to a lesser degree. The long-term effects noticed in this study highlight the importance of providing proper nutrition to pregnant ewes.

Influence of Prolactin Secretion Changes on Sperm Head Size and Freezability in Ibex and Mouflon.

Aim: This work examined the influence of induced changes in prolactin (PRL) secretion on sperm cryoresistance of ibex and the mouflon. Materials and Methods: PRL secretion was modified in a first experiment by the use of bromocriptine (BCR, dopamine agonist) during the non-breeding season, and in a second experiment by the use of sulpiride (SLP, dopamine D2-receptor antagonist) during the rutting season. Slow and ultra-rapid freezing protocols were used to cryopreserve sperm samples. Results: BCR decreased blood plasma PRL concentrations, whereas SLP increased them. Cryoresistance ratios (CRs) for curvilinear velocity (VCL), straight-line velocity (VSL), and average path velocity (VAP) in BCR-treated mouflons were lower than in controls using slow-freezing (p < 0.05), while CRs of motility and morphologically normal sperm of BCR-treated mouflons were greater than controls with ultra-rapid freezing (p < 0.05). BCR increased the head sperm dimensions in ibexes (p < 0.001); conversely, BCR decreased the head dimensions in mouflons (p < 0.001). CR-motility, CR-amplitude of lateral head displacement (ALH), CR-viability, and CR-acrosome integrity in SLP-treated mouflons were lower than in controls with slow-freezing (p < 0.01); CR-viability and CR-acrosome were lower than controls with ultra-rapid freezing (p < 0.05). In ibexes, CR-ALH was lower for SLP-treated (p < 0.05). SLP treatment increased head dimensions in ibexes (p < 0.001) but did not affect the sperm head of mouflons. Conclusion: Our findings show that high levels of blood plasma PRL negatively affect the cryoresistance of ibex and mouflon sperm.

Single or repeated immunization against GnRH fails to completely abolish spermatogenesis in dwarf bucks (Capra hircus).

In both captive wildlife and production animals is important to develop strategies for population control. Immunization against GnRH is an easy and inexpensive immunocastration method that reduces the concentration of testosterone and decreases sperm quality. However, its effectiveness depends on the species and repetition of the treatment. This study aimed to compare the effectiveness of a single treatment (initial immunization plus a booster with Improvac) vs repeated treatment (six doses of Improvac) to inhibit testicular function and maintain the contraceptive status during long periods in bucks. Three Dwarf bucks (Capra hircus) received two doses of Improvac, the first on Week 0, and the booster 4 weeks later (single immunization, group SI) while three Dwarf bucks received one dose of Improvac every 6 months during 3 consecutive years (repeated immunization, group RI). The other three Dwarf bucks remained untreated (control bucks, group CON). Bucks from RI had a greater decrease in scrotal circumference, testosterone concentration, male odor intensity, and sperm quality than SI bucks. However, there were no differences between SI and CON bucks in any of the variables studied. Overall, repeated treatment of Improvac decreased the testicular function of Dwarf bucks, although did not produce complete infertility. However, the repetition of the treatment produced more intensive negative effects, indicating that the strength of the effects of Improvac is rapidly lost in bucks.

Administration of carbetocin-a long-acting oxytocin analogue-before sperm collection by transrectal ultrasound-guided massage of the accessory sex glands in bucks (Capra hircus) and ibexes (Capra pyrenaica).

Transrectal ultrasonic-guided massage of the accessory sex glands (TUMASG) is a technique that allows collecting semen requiring few electrical stimuli or even no pulse. A long-acting analogue of oxytocin (carbetocin, 0.1 mg) was i.v. administered before TUMASG in 10 conscious bucks (Experiment 1) and 10 anaesthetized Iberian ibexes (Experiment 2) to shorten the time of semen collection, decrease the number of electrical stimuli and/or improve the semen quality. The ejaculated volume, concentration, quality parameters and kinetics variables of the sperm were determined in fresh semen. The time length of the procedures and the number of electric pulses applied were recorded. Furthermore, stress response indicators (number of vocalizations in Experiment 1; heart and respiratory rates, rectal temperature, cortisol levels, totals proteins and neutrophil-to-lymphocyte ratio in Experiment 2) were documented. In bucks, the administration of carbetocin tended to shorten the time needed for semen collection but no-showed differences in the fresh seminal quality. In the Iberian ibexes, there were no significant differences between groups in the time length of procedures or in the number of animals that ejaculated. Carbetocin administration only reduced the respiratory rate, did it modify fresh semen characteristics in ibexes. In conclusion, the administration of carbetocin did not appear as a useful tool to improve welfare during semen collection with TUMASG or semen quality in conscious bucks and anaesthetized ibexes, having only slight advantages related to the procedure.

Biostimulation and pheromones in livestock: A review.

This review examines aspects of the phenomenon of biostimulation in swine, goats, sheep, cattle and deer, to improve the collective knowledge and exploitation of its relevant mechanisms and effects in animal production. The long-term goal is to implement biostimulation strategies that benefit livestock reproduction and production while being both cost-effective and socially acceptable.

Administration of butorphanol with ketamine/xylazine sedation reduces the negative responses to electroejaculation in rams.

This study aimed to identify the possible advantages of administering butorphanol (BUT), associated with ketamine/xylazine (KX) sedation or not, for semen collection using electroejaculation (EE) in rams. Fifteen rams received four treatments in a cross-over design using a 2 × 2 factorial arrangement. The treatments were 1) control; 2) received KX; 3) received BUT; and 4) received both treatments. The responses to the procedures regarding heart rate, respiratory frequency, and rectal temperature were recorded, glucose and creatine kinase were measured, and semen quality was determined. More pulses were required when BUT was administered (P = 0.0067), but rams vocalized fewer times (P = 0.046). The administration of KX also tended to reduce the respiratory frequency (P = 0.068) and rectal temperature (P = 0.089), with no other effects. The administration of BUT reduced the heart rate (P < 0.0001), and there was an interactive effect between the administration of BUT and time on the heart rate (P < 0.0001), respiratory frequency (P = 0.01), and rectal temperature (P = 0.047). The administration of BUT reduced the heart rate increase immediately after EE (P < 0.0001). The respiratory frequency following EE was greater when BUT was administered (P < 0.0001), but the administration of BUT reduced the rectal temperature at the same time (P = 0.002). Glucose concentration was greater when BUT was administered (P < 0.0001). The only significant effect on the ejaculate characteristics was from the interaction between KX and BUT on sperm concentration (P = 0.004). The administration of KX alone increased sperm concentration (P = 0.035), but when BUT was added to KX, sperm concentration decreased (P = 0.002). Moreover, sperm concentration was greater when only BUT was administered than when KX and BUT were administered simultaneously (P = 0.037). The addition of BUT markedly decreased most negative responses more effectively than sedation with KX alone. In conclusion, BUT appears to be an interesting alternative to reduce the welfare concerns raised by the use of EE in rams; however, its possible effects on the ejaculate characteristics when associated with other anesthesia/sedation drugs require further study.

Calf-cow and bull-cow management in buffaloes: Effects on growth, productive and reproductive performance of mothers and their calves.

The aim of the first study was to determine the influence of the calf handling (restricted or full contact) and fenceline bull stimulation on performance of mothers and their calves. The aim of the second study was to determine the relative impact of calf-bull contact, comparing the result of restricted calf and no bull with that of fenceline calf contact and direct bull contact on the performance of mother buffaloes and their calves. In Experiment 1, 24 mother-calf dyads were allocated to three treatments: NCB (no calf-mother-bull contact), RC-FBC (restricted calf and fenceline bull contact) and FC-FBC (fenceline calf and fenceline bull contact). In Experiment 2, another 24 mother-calf dyads were allocated to two treatments: RC-NB (restricted calf and no bull contact) and FC-DBC (fenceline calf and direct bull contact). In Experiment 1, average daily gain (ADG) was greater in FC-FBC than RC-FBC and NCB calves (p < .05). Average dry matter intake (DMI) was greater in FC-FBC than RC-FBC and NCB calves. DMI of buffaloes was greater in FC-FBC than RC-FBC and NCB. Daily milk yield of buffaloes was more (p < .05) in FC-FBC (10.2 ± 0.2 kg) than RC-FBC (8.4 ± 0.2 kg) and RC-FBC (7.8 ± 0.2 kg). There were no statistical differences observed in the interval from calving to first oestrus, first service, service period among three groups. In Experiment 2, ADG's and DMI were greater in FC-FBC calves than RC-FBC (p < .05). DMI of buffaloes was greater in FC-DBC than RC-NBC (p < .05). Daily milk yield of buffaloes was greater (p < .05) in FC-DBC (11.6 ± 0.2 kg) than RC-NBC (8.3 ± 0.2 kg). The first oestrus (51.5 ± 3.1 vs. 103.2 ± 7.2), days to first service (74.8 ± 3.5 vs.112.0 ± 7.6) and service period (78.8 ± 4.8 vs.118.9 ± 8.3 days) were lower (p < .05) in FC-DBC than RC-NBC buffaloes. The fenceline calf-mother contact increased the growth rate, FCR, and feeding efficiency of buffalo calves; reduced some stress responses and improved the productive performance of buffalo mothers. Further, mother-bull contact stimulated the post-partum reproductive performance of buffaloes in fenceline calf contact.

Effect of biostimulation on growth rate and reproductive development of Bos indicus dairy heifers.

The present study aimed to compare the growth rate, feeding behavior, reproductive development, and concentrations of GH and leptin in Sahiwal heifers exposed to direct bull contact, bull contact through a fenceline, or isolated from bulls. Overall, 24 heifers were allotted to three treatment groups (n = eight/group) based on birth weight, body weight, and age. Heifers from the non-exposed group (NBE) remained isolated from bulls; heifers stimulated by fenceline bull contact (FBE) remained continuously exposed to bulls through a fenceline, and heifers with direct bull contact (DBE+FBE) had direct contact with a bull during 6 h/day plus continuous fenceline bull exposure for the entire 24 h period. It was considered that heifers attained puberty when progesterone concentration was >1 ng/mL. Biostimulated heifers achieved puberty at both a lower age and body weight (P < 0.05) than NBE heifers. Overall, average daily gain (g/day) was greater in DBE+FBE (516.3 ± 4.5) and FBE (501.6 ± 4.3) than in NBE (441.8 ± 2.9, respectively; P < 0.01). Leptin and growth hormone concentrations were significantly greater in FBE and DBE+FBE than NBE heifers. Both groups of biostimulated heifers devoted more time eating than NBE heifers, P < 0.05). In conclusion, biostimulation of Sahiwal heifers, either by exposing them to bulls through a fenceline or by both fenceline exposure and direct contact, reduced the age of puberty and increased growth performance. Overall, fenceline bull exposure can be recommended as an easy handling management to stimulate reproductive precocity and growth rate in heifers.

Lambs are more stressed at early weaning when housed with their twin.

The objective of this study was to compare the behavioural and immunological responses of twin lambs housed together with their siblings or not after weaning. The study was performed with seven multiparous Milchschaf ewes and their twin lambs (n = 14), which were weaned abruptly at 63 days of age and assigned to two experimental groups: (1) lambs that were housed together with their sibling after weaning (group GT, n = 6) and (2) lambs that were separated from their siblings and remained with other lambs from the same flock (group GS, n = 8). Before and after weaning, the distance between twins, the number of times in which the sibling was the closest lamb, the lambs' behaviours, and the average daily gain were recorded. The lambs' immune response was assessed with the phytohemagglutinin skin test after weaning. The closest lamb before weaning was the sibling in all cases (P < 0.0001 for all). The frequency in which GT lambs were observed closest from its twin increased on the day of weaning (P = 0.002). During the day of weaning, GT lambs vocalised and paced more than GS lambs (P = 0.001 and P = 0.01, respectively). Twenty-four h after the phytohemagglutinin injection, the skinfold thickness was greater in GS than GT lambs (P = 0.03). In conclusion, twin lambs housed together with their siblings were more stressed at weaning, displaying more intensive behavioural changes and a poorer immunological status than twin lambs housed separated from their siblings.

Progestogen supplementation during superovulation leads to higher embryo viability and TGFB1 gene expression in sheep.

This study aimed to compare the effect of the administration of either medroxyprogesterone acetate (MPA) or progesterone (P4) in superovulation (SOV) treatments applied during the first follicular wave on follicular development, embryo yield, and the expression of genes related to pluripotency maintenance, differentiation of the trophectoderm, cell growth and differentiation, apoptosis and energy metabolism in sheep embryos. The estrous cycle of 36 multiparous ewes was synchronized with a short protocol, and the animals were randomly allocated to three groups. At the beginning of SOV, 12 ewes per treatment received an intravaginal sponge impregnated with 60 mg of MPA (TMPA), or an intravaginal device containing 0.33 g of P4 (TP4), or received no progestogen treatment (CON). The device was kept until the fifth dose of FSH. Ewes were mated with five fertile rams. Gene expression was performed by RT-qPCR using grade I and II blastocysts. The numbers of corpora lutea, total structures and viable embryos recovered per ewe were similar (P > 0.05) among groups. However, the viability rate was higher in TP4 (71.9 ± 16.3%) compared to CON (24.4 ± 16.8%; P = 0.01) and similar to TMPA (49.9 ± 16.3%; P = 0.2). Similarly, when compared with CON, treatment with P4 or MPA positively regulated the TGFB1 transcript involved in cell proliferation and differentiation (P = 0.01 and P = 0.03, respectively). In conclusion, supplementation with P4 during the first follicular wave of the estrous cycle improves embryo viability and alters the expression of the TGFB1 gene.