Frequent social regroupings affect corporal and reproductive development, metabolic status, and behavioral time budget in dairy heifers.

We aimed to evaluate the corporal and reproductive development, metabolic status, and behavioral patterns of resident dairy heifers subjected to social regroupings (SR). Holstein replacement heifers (153.3 ± 16.1 kg, 11 months old) were homogeneously allocated to: 1) Control (CON; n = 14 resident + 5 "permanent") and 2) Regrouped (RG; n = 14 resident + 5 "changing"). "Changing" heifers were exchanged for 5 novel heifers every 21 d over 205 days (total = 10 SR). At each SR, body weight, wither height, body condition score (BCS), eating, ruminating, lying and standing behaviors were recorded, and blood hormones and metabolites were determined. Behavior was registered through scan sampling every 10 min., and estrus was detected using patches. Wither height and BCS were greater in CON than RG at SR9 and 10, and at SR4 and 5, respectively (P < 0.01). Control heifers showed first heat earlier (93 ± 9 d vs 126 ± 14 d; P = 0.03) and presented greater insulin growth factor- 1 (171.3 vs 120.0 ng/ml ± 10.1; P < 0.01) and glucose (4.3 vs 4.2 mmol/L ± 0.07; P = 0.04) concentrations than RG, while non-esterified fatty acids concentration was greater in RG (0.35 vs 0.30 mmol/L ± 0.04 P = 0.04). Regrouped heifers were observed more times eating (0.45 vs 0.33 ± 0.01), but fewer times ruminating (0.21 vs 0.24 ± 0.01) than CON (P < 0.01). Frequent SRs negatively affected corporal and reproductive development and energy metabolism, and altered behavioral patterns in dairy heifers.

Evidence of cooperative calves' care and providers' characteristics in zebu cattle (Bos indicus) raised under extensive conditions.

Communal rearing has been reported in several mammals, including wild ungulates. However, until now, there was no evidence of any alloparental care in the Bos genus. To test the hypothesis that calves' groups are formed under the care of specific cows, a herd of 31 peri-partum zebu cows raised under pasture conditions were used. Groups of ≥ 3 individuals within a 10-m diameter were estimated using aerial pictures taken every other day at 7:00, 10:30, 13:30, 16:00, and 18:00 h, during 6 weeks. Temperament (exit speed, flight distance, intensity of reaction), age, and parity of each cow were registered. A total of 142 groups were observed, and in all of them, at least one calf was present. A total of 75% of the groups were more calves than cows, and in 65.4% of the cases, there were 1 to 3 cows with 2 to 32 calves. While there were no groups integrated only by cows, there were 3.5% integrated only with calves. The most frequent group was formed by 2 calves and 1 cow (14.8%). Parity was positively related with the number of times that a cow was observed in a group (R2 = 0.19, P = 0.01) and with the number of groups in which her calf was present (R2 = 0.16; P = 0.03). The results of the temperament tests were unrelated to the total number of groups in which a cow was observed nor the number of groups with or without its calf. It was concluded that zebu calves congregate in newborn groups in companion with one or more adults, preferably high parity cows, regardless of their temperament.

Vaginal biota number is smaller in tailed than docked hair ewes (Ovis aries), but is not affected by copulation.

A greater accumulation of feces could facilitate the entrance of bacteria or inert particles into the vagina, particularly while mating tailed ewes. Two experiments were performed to determine if the tail has an active role in the growth of bacterial flora and the entrance of inert material in the vagina after mating, during induced or natural estrus. Twenty ewes were used, 10 tailed and 10 docked. All ewes displayed estrus after CIDR treatment, and half of them; 5 tailed and 5 docked were exposed to rams during the first experiment. For the second experiment, the rest of the animals were mated 15-17 d later at spontaneous estrus. In the induced estrus, no differences in the number of CFU/mL in docked or tailed ewes were observed before mating, but after mating, CFU values tended to be greater in docked than tailed ewes, and the number of inert particles was greater in docked than tailed ewes (5.8 ± 1.3 vs 1.6 ± 0.6, P = 0.024). During natural estrus, docked ewes had less CFU/mL than tailed ewes (19.6 × 103 ± 0.4 vs 80.0 × 103 ± 0.0, P = 0.006) before mating, and a similar tendency was maintained after mating, when the number of inert particles was similar in docked and tailed ewes. Staphylococcus and Escherichia were observed in the induced estrus, while in the natural estrus, even though these were the more frequent, five other genera of bacteria were observed. It was concluded that the presence of the tail protects the vaginal environment against increases of the biota load.

Social dominance in prepubertal dairy heifers allocated in continuous competitive dyads: Effects on body growth, metabolic status, and reproductive development.

The objective of this study was to compare the body weight (BW) and size, metabolic status, and reproductive development of dominant and subordinate prepubertal dairy heifers allocated in competitive dyads. Sixteen Holstein and Jersey × Holstein prepubertal heifers (means ± SEM; 250.8 ± 9.8 d; 208.5 ± 13.9 kg of BW) were assigned to 8 homogeneous dyads according to breed, age, and BW. Dyads were housed in pens separated 1 m from each other during 120 d, receiving a total mixed ration on a 5% restriction of their potential dry matter intake, and had access to the same feeder (60 cm) throughout the experiment. Dominant and subordinate heifers were defined based on the winning agonistic interactions in each dyad. Body development was recorded every 20 d in all heifers, and blood samples were collected on the same days to determine endocrine and metabolic status. The maximum follicle diameter, number of follicles >6 mm, and the presence of corpus luteum were observed weekly by ultrasound. Heifer BW (269.3 vs. 265.3 ± 1.5 kg) and average daily gains (0.858 vs. 0.770 ± 0.02 kg/d) were greater in dominant than subordinate heifers. On d 30, 37, and 53, dominant heifers had more follicles than subordinate heifers, and maximum follicle diameter was greater in dominant than in subordinate heifers (10.0 vs. 9.0 ± 0.3 mm). Dominant heifers achieved puberty earlier than subordinate heifers (313.9 ± 4.9 vs. 329.6 ± 5.7 d) with similar BW (279.4 ± 2.6 vs. 277.4 ± 5.8 kg). Glucose concentrations were greater in dominant than subordinate heifers (89.2 vs. 86.8 ± 1.2 mg/dL), but cholesterol concentrations were greater in subordinate than dominant heifers (86.1 vs. 90.2 ± 2.6 mg/dL). We concluded that, under continuous competitive situations, dominant heifers were more precocious than subordinate ones, achieving an earlier puberty. Dominant heifers had greater body growth and glucose concentrations than subordinate heifers, which may be responsible, at least in part, for the differences on reproductive development between heifers of different social status.

Ejaculation does not contribute to the stress response to electroejaculation in sheep.

Electroejaculation procedures (EEPs) provoke stress; nevertheless, ejaculation produces physiological changes similar as those usually used to measure stress responses. The application of EEP to animals that cannot ejaculate-as ewes-may be useful to discriminate the responses induced by ejaculation from those provoked by EEP. The aim was to determine the stress response to EEP in rams and ewes. The EEPs were applied to 10 rams and 10 ewes during the non-breeding season, and the number of vocalizations, the heart rate, rectal temperature, serum cortisol concentration, biochemical and haematological parameters were measured. Overall, EEP provoked increases in cortisol concentration, glycaemia, rectal temperature and concentration of creatine kinase (all them: p < .0001) as well as relative concentration of granulocytes (p = .003) and absolute granulocyte concentration (p = .0002) in both, rams and ewes. Heart rate, relative concentration of lymphocytes (p = .001), haematocrit (p = .02) and haemoglobin (p = .045) decreased in animals from both genders after EEP. Besides, cortisol (p < .0001), rectal temperature (p = .002) and glycaemia (p = .001) were greater in ewes than rams, and creatine kinase also tended to be greater in ewes than rams (p = .054). On the other hand, the number of animals that vocalized (p = .006), white blood cells (p = .02) and absolute lymphocytes (p = .02) were greater in rams than ewes. The general trends show a similar pattern of stress responses in animals from both genders. Therefore, we concluded that ejaculation does not contribute to the stress response provoked by the EEP. This procedure also provokes muscular damage and probably pain.

Antler velvet is thicker in adult than in yearling pampas deer (Ozotoceros bezoarticus): a histological study.

BACKGROUND: Antlers are lined by soft velvet tissue during antler growth. Later, the velvet is shed before rut onset. There are no detailed histological descriptions of the growing velvet, nor whether the velvet changes according to stag age. Our aims were to: 1) describe the basic histology of pampas deer antler velvet from adult and yearling males; and 2) determine the influence of age and time of antler growth on velvet's tissues morphometry. MATERIALS AND METHODS: Samples were collected from 10 stags allocated in two groups, either adult (3-5 years old, n = 5) or yearling males (2 years old, n = 5). The day of antler cast was recorded for each animal. In spring, the stags were anaesthetised and velvet samples were collected from the third tine's distal end. Samples were described qualitatively and a restricted morphometrical analysis of the antler velvet was performed. RESULTS: The number of keratinocyte layers and the thicknesses of: total epidermis, corneum, intermediate and basale epidermal strata, total dermis, superficial and deep dermis were determined. Age and days after antler casting positively influenced in conjunction epidermal thickness (p = 0.037), and tended to influence both stratum intermedium (p = 0.076) and stratum corneum (p = 0.1) thicknesses. Age influenced stratum corneum thickness (p = 0.04). The pampas deer antler velvet lacked both sweat glands and arrector pili muscles. CONCLUSIONS: The deep dermis was densely irrigated but displayed abundant and well developed collagen bundles. Both total epidermal and stratum corneum thicknesses related positively to the age of the animals but were not to the time since antler cast.

Competition Between Different Social Ranked Rams has Similar Effects on Testosterone and Sexual Behaviour Throughout the Year.

Dominant rams have preferential access to females, as they frequently interrupt sexual behaviour from subordinated. Testosterone concentrations are directly linked to sexual and aggressive behaviour and have important variations along the year. Therefore, it may be expected that the effects of dominance relationships on reproductive behaviour differ according to testosterone concentrations, and thus to the period of the year. The aim of this study was to compare the effects of dominance relationships on testosterone and sexual behaviour in different moments of the year in rams. Twelve rams were maintained in a single group. Social rank was determined in January (maximum reproductive development), May (regression of the reproductive status) and August (lowest reproductive activity), and the four rams with higher (HR) and the four with lower (LR) success index were used. Testosterone serum concentration was weekly measured four times during each experimental period. Sexual behaviour was evaluated in each period with an oestrous ewe, and with the oestrous ewe and another ram from the other social rank (each HR with each LR ram). Testosterone concentration was greater in HR than LR rams in January (p = 0.03), and all the behaviours were displayed more frequently in non-competitive than in competitive tests (p < 0.05). Rams modified their sexual strategy in competitive environments decreasing the display of sexual behaviour independently of their social status. This effect was observed consistently throughout the year: high-ranked rams have greater testosterone concentrations than LR rams only during the pre-rut, when they naturally compete to join the groups of ewes.

Vocalizations during electroejaculation in anaesthetized adult and young pampas deer (Ozotoceros bezoarticus) males.

The aim of this study was to characterize the vocalizations produced during electroejaculation under general anaesthesia in pampas deer males and to determine whether the characteristics of those vocalizations differ in adult and young pampas deer males. Electroejaculation was applied to 13 adults (AM) and 13 young (YM) males under general anaesthesia. Vocalizations were digitally recorded, and the number and duration of vocalizations, the latency in relation to each voltage, the total time vocalizing, and the structure of the fundamental frequency (F0) [initial frequency (F(start)), maximal frequency (F(max)), minimal frequency (F(min)) and final frequency (F(end))] were analysed. No male vocalized with 0 V; the number of animals that vocalized increased at 2 and 3 V and increased again at 4, 5 and 6 V (p < 0.05). The latency time from the beginning of each series (each voltage) decreased until 4 V (p < 0.01). The number of vocalizations/voltage increased from 4 V (p < 0.05). The length of each vocalization and the total time during which animals vocalized were greater in YM than AM (p = 0.02 and p = 0.01, respectively). Similarly, the fundamental frequencies were higher in YM than AM (p ≤ 0.05). Overall, we concluded that the vocalizations emitted during electroejaculation in pampas deer under general anaesthesia are related to the voltage applied during the process. Young males vocalize more time, probably due to a greater sensibility to the electric stimulation. The differences in the characteristics of the vocalizations between adult and young males may be related to the anatomic differences in the neck of adult or young males.

Vaginal histological changes after using intravaginal sponges for oestrous synchronization in anoestrous ewes.

To characterize the histological and cytological vaginal changes generated by the use of intravaginal sponge (IS) applied in oestrous synchronization treatments in ewes during mid-non-breeding season. Thirty-five multiparous ewes were allocated to three experimental groups according to the moment in which the samples were taken: (i) ewes treated with IS containing 60 mg of medroxyprogesterone acetate for 14 days, sampled the day of IS removal (group ISR; n = 10), (ii) or after sponge removal at time of oestrus or 72 h after removal (group AR; n = 14) and (iii) ewes without sponge treatment that were sampled at the day of IS removal of the other groups (group CG; n = 11). Vaginal biopsies and cytological samples were taken from the anterior vaginal fornix area. The vagina of the CG group had a stratified squamous epithelium with a moderate degree of cellular infiltration with lymphocytes and plasma cells in the lamina propia. Treated ewes (ISR and AR) had epithelial hyperplasia and hypertrophy. ISR ewes had haemorrhage and perivascular infiltrate and an increased number of epithelial cells, neutrophils, macrophages and erythrocytes at IS removal. The use of IS generated histological and cytological alterations in the vaginal wall when used for oestrous synchronization in anoestrous ewes.

Social rank affects the endocrine response to frequent regroupings in grazing dairy heifers.

The objectives of this study were to determine the social behavior response to repeated social regrouping (SR), and if social rank and the changes of social rank affect the growth rate and some metabolites and hormones linked to energy status, in "resident" replacement dairy heifers subjected to SR for 205 d. Fourteen dairy heifers (153.3 ± 16.1 kg; 9 to 11 mo old), maintained under grazing conditions, were regrouped every 21 d with 5 new animals (total = 10 SR). Two days after each SR, heifers were weighed and their withers height was measured, and blood samples for nonesterified fatty acids, glucose, and IGF-1 were taken. Concentrations of nonesterified fatty acids, glucose, and IGF-1 were taken. Social behavior was registered by continuous sampling and social status was calculated by the ETlog software, considering the total number of agonistic interactions on 2 d before and 7 d after each SR. A dominance scale was constructed in each SR, and heifers were categorized as high-ranked (HRA), medium-ranked (MRA), and low-ranked (LRA). In addition, the social rank in the first and the last 5 SR were compared, resulting in 3 categories: heifers that remained in the same social rank (Mai), and heifers that lowered (Low) and raised (Rai) their social ranks. Variables were analyzed by repeated measures using a generalized lineal mixed model, considering the social rank in each SR or the change in social rank, the number of SR and their interaction as main effects, and the farm of origin and animal as random effects. Heifers performed more agonistic (2.6 vs. 1.8 ± 0.6, day of SR and 7 d later, respectively) and total (3.8 ± 1.2 vs. 2.5 ± 0.7, day of SR and 7 d later, respectively) interactions on the day of each SR than 7 d after, whereas the number of interactions decreased after the first 2 SR. Medium-ranked heifers presented greater IGF-1 concentrations than HRA heifers at SR1, SR4, and SR9, and than LRA heifers at SR3 and SR4, whereas IGF-1 concentrations were greater in HRA heifers than MRA heifers at SR3 and SR7. In addition, LRA heifers had greater IGF-1 concentrations than MRA ones at SR3 and compared with HRA heifers at SR9. Heifers that lowered their social had greater IGF-1 concentrations than Mai heifers along the SR (132.5 ± 17.1 vs. 97.8 ± 11.2 ng/mL, Low and Mai heifers, respectively) and at SR1, SR3, and SR9. In conclusion, although regrouping animals according to their characteristics can facilitate farm handling, it should be considered that endocrine profile may be affected according to heifers' position in the social hierarchy.

A single administration of carbetocin before electroejaculation increases the insemination doses produced from each ejaculate in rams.

The aim of the study was to determine the effect of carbetocin administration (a long-acting analog of oxytocin) 20 or 10 min before electroejaculation (EE) on the duration of semen collection procedure, quantitative and qualitative characteristics of the ejaculate, and stress biomarkers in rams. Semen was collected from 12 Corriedale rams (age, 2.5-5.5 years old) with EE, in a Latin-square design, administrating carbetocin (0.2 mg/100 kg of body weight i.v.) 20 or 10 min before EE, or without carbetocin administration (CB-20, CB-10, and CON treatments, respectively). Each treatment was applied to different rams every 3-4 days, allowing all the rams to receive all three treatments. Carbetocin administered 20 or 10 min before EE increased the number of sperm ejaculated (P = 0.01), the semen concentration (P = 0.02), the number of insemination doses collected in a single collection (P = 0.01), and the number of insemination doses collected/electrical pulses administered (P = 0.05) compared to control rams. Carbetocin administered 20 or 10 min before semen collection prolonged the time required for EE and the number of pulses administered during EE compared to CON rams (P < 0.03 for both). The CB-10 rams required the administration of more electrical pulses during ejaculation than CON rams (P = 0.001), and CB-20 treatment tended to require more electrical pulses than CON rams (P = 0.06). The volume of the ejaculate was greater in CB-10 than in CON rams (P = 0.01), and that of CB-20 treatment tended to be greater than CON rams (P = 0.08). The percentage of sperm with intact membrane was greater in CB-20 than in CON rams (P = 0.01). Total protein, albumin, and globulin concentrations were lower immediately after carbetocin administration 20 or 10 min before EE. The treatments did not affect cortisol concentration, glycemia, rectal and surface temperatures, heart rate, and facial expressions. Carbetocin administration before EE of rams improved the quantitative and qualitative characteristics of the ejaculate, duplicating the number of insemination doses collected. It can be a promising treatment to obtain a greater quantity of doses to inseminate with a lower frequency of semen collections, reducing the negative impacts of EE on animal welfare.

Administration of a single dose of long-acting injectable progesterone formulation reduces the stress response to weaning in anestrous ewes.

High circulating progesterone concentrations decrease the responses to stressful situations in farm ruminants. We hypothesized that administering a single dose of long-acting progesterone formulation reduces the stress response of anestrous ewes to weaning. The aim of this study was to compare the behavioral, cortisol, and blood protein responses to weaning of anestrous ewes treated or not, with a single dose of a long-acting progesterone formulation. A complementary aim was to characterize the bioavailability of progesterone after this treatment. Thirty-six multiparous single-lambing Corriedale ewes and their lambs were used in this study. The lambs were weaned at 6:30 h when they were 65 d old (d0), and were taken to another paddock without chemical, visual or auditory contact with their mothers, while the ewes remained in the same paddock. Immediately before weaning, while 19 ewes received oil based long-acting progesterone formulation, other 17 ewes remained as controls, receiving sunflower oil. Twelve ewes from each group were used for behavioral recordings, the other 5 untreated ewes and 7 treated ewes were used to characterize the cortisol response and the progesterone profile. Behaviors were recorded every 10th min for 3 h in the morning and 3 h in the afternoon on day minus 3, d0 and d2, and expressed as percentage of recordings each animal displayed each behavior on each day. Treated ewes were recorded more times standing up than ewes on the day of weaning (P < 0.05), but the reverse result was found 2 d after (P < 0.01). Treated ewes were recorded more times lying down than control ewes on d2 after weaning (P < 0.0001), when treated ewes were observed fewer times walking than control ewes (P = 0.0004), as also happened the day of weaning (P < 0.0001). On the day of weaning, treated ewes grazed and paced less than control ewes (P = 0.001 and P = 0.009). Treated ewes ruminated more than control ewes on the day of weaning (P = 0.02) and 2 d later (P = 0.0002). Control ewes also secreted more cortisol than progesterone-treated ewes (P = 0.03), with no effect of the treatment on the concentration of total proteins, albumin or globulins. While control ewes never had luteal progesterone concentrations (>0.5 ng/mL), treated ewes achieved luteal progesterone concentrations 2 h after its administration, and remained well above luteal levels until 15 h after administration. The administration of a single dose of long-acting progesterone formulation appears to be a viable choice in reducing the stress to weaning in ewes. Ewes treated with progesterone coped better with weaning, returning to their normal basal behavior earlier than untreated ones, and secreting lower cortisol levels.

Testicular fluid content and scrotal surface temperature increase with rams' sexual activity.

Contact with oestrual ewes induces an increase in LH and testosterone concentrations in rams. LH provokes an increase in testicular capillary permeability in rodents and an increase in testicular fluid in rams. Therefore, the objectives of the present experiment were to determine whether contact with oestrual ewes, including courtship and mating, induces an increase in testicular fluid content and scrotal temperature in rams. During the breeding season, after 2 weeks isolated from females, a total of 18 tests were performed using one ram with one ewe. The rams were allowed to court and mate the ewes during 20 min. Testosterone blood concentrations were measured by RIA from blood samples taken before and immediately after each test. Rectal, scrotal surface and anal skin temperatures were measured before the test, at the end, and 30 min later. At the same moments, ultrasonographic examinations of the testes were performed. Testosterone concentrations increased after the tests (p = 0.016), and ultrasound images were darker at the end of the tests and 30 min later (p < 0.0001). Rectal, anal skin and scrotal temperatures increased at the end of the test, but decreased 30 min later to initials values. The stimulus of oestrual ewes determined an increase in testosterone secretion, which was associated with an increase in testicular fluid content. Fluid content remained increased at least for 30 min after the end of the ram-ewe contact. Contact with oestrual ewes triggered an increase in testicular fluid that remained higher after the end of the test.

Physiological and biochemical parameters in response to electroejaculation in adult and yearling anesthetized pampas deer (Ozotoceros bezoarticus) males.

The aim of this study was to characterize changes in physiological and biochemical parameters during electroejaculation (EE) under general anaesthesia in adult and yearling pampas deer males (Ozotoceros bezoarticus). The relation between heart rate, pulse rate, respiratory rate and oximetry with EE voltages was studied. The changes in cortisol, alkaline phosphatase, creatine kinase, aspartate aminotransferase and rectal temperature were determined before and after electroejaculation (BEE and AEE). Heart rate and pulse rate values increased during EE, with a greater increase in heart rate in adults (p < 0.01). Respiratory rate and SpO(2) were not affected by EE or category. The rectal temperature decreased in adults and yearlings during EE (p = 0.0001). Alkaline phosphatase, creatine kinase and aspartate aminotransferase concentrations increased AEE (p < 0.001, p < 0.01 and p < 0.05, respectively). Alkaline phosphatase and creatine kinase concentrations were greater in young than in adult males (p < 0.05). In conclusion, the EE under general anaesthesia in the pampas deer provoked increases in heart and pulse rates, as well as in creatine kinase, aspartate aminotransferase and alkaline phosphatase concentrations, and a decrease in rectal temperature in both categories. Oximetry values were especially low during the procedure. Heart rate increase was greater in adult males, and alkaline phosphatase and creatine kinase concentrations were greater in yearlings.

Daily variation of the cortisol and insulin concentration, glycemia, surface temperature, and behavior patterns due the administration of equine Chorionic Gonadotropin in rams.

Sex steroids can modulate the circadian rhythmicity of some physiological and behavioral functions of sheep. During the non-breeding season, Corriedale rams have a low testosterone concentration, but the administration of equine Chorionic Gonadotropin (eCG) stimulates its secretion. Therefore, the daily variation of cortisol and insulin concentrations, glycemia, behavioral pattern (eating, ruminating, standing, lying, and sleeping), and rostral and eye surface temperatures were compared in rams treated or not treated with eCG during the non-breeding season [between August (late winter) and September (early spring)]. Twenty Corriedale adult rams (BW 63.4 ± 7.3 kg; BCS: 3.5 ± 0.5; mean ± SD; age: 2-3 years old) were randomly assigned to 1 of 2 treatments: a) Treated: administration of 1000 IU of eCG intramuscularly and b) Control: control, without application of eCG. All the rams were managed under the same feeding and environmental conditions (individual pens outdoors). All variables were measured each hour for 26 h, except testosterone and insulin that were measured at 09:00, 10:00, 12:00, 15:00, 18:00, 21:00, 22:00, 24:00, 03:00, 06:00, 09:00 and 11:00 h. Testosterone and cortisol concentration were greater in Treated than Control rams (testosterone: 32.7 ± 0.7 nmol/L vs 5.8 ± 0.7 nmol/L; P <0.0001; cortisol: 11.3 ± 0.6 nmol/L vs 9.9 ± 0.6 nmol/L; P =0.02). The eye surface temperature was 0.9°C lower in the Treated than in the Control rams (P =0.004). The characteristics of the daily variation pattern of cortisol, glycemia, glycemia:insulin ratio, and surface temperature were not affected by the treatment, the acrophases being at ∼06:00 h, ∼18:00 h, ∼08:00 h, and ∼11:00 h, respectively. The acrophase of insulin concentration was observed earlier in Treated than in Control rams (13:02 ± 0:56 vs 15:47 ± 0:53; P =0.04). Additionally, the acrophase of the time spent eating was advanced in Treated rams (09:48 ± 00:16 vs 10:20 ± 00:16; P =0.04) and sleeping (21:39 ± 00:57 vs 02:02 ± 01:06; P <0.0001). Treated rams slept less time than Control rams (P =0.04). In conclusion, the administration of eCG modulated the daily variation pattern of insulin concentration and the behavioral pattern (period in which rams were observed eating and sleeping). Nevertheless, although there was a greater cortisol concentration and reduced eye surface temperature, the administration of eCG did not modify their daily variation pattern, suggesting that this is robust, limiting the effect of testosterone on their basal pattern.

Testicular fluid content evaluated by ultrasound image computer-assisted analysis increases with small-dose multiple GnRH injections in rams.

The aim of the work was to determine whether multiple small doses of GnRH induce an increase in testicular blood flow and scrotal temperature in rams. The experiment was performed during the late breeding season (May-June) with 14 one-year-old rams. Seven rams received hourly doses of 7 ng of a GnRH analogue (busereline acetate) iv starting at 8:00 on the morning, and the other seven rams remained as controls. One week later, treatments were overcrossed. One hour before the first GnRH dose (7:00), and 0, 1, 2, 4, 7 and 10 h later, ultrasonographic examinations of the testes were performed with a B-mode ultrasound scanner with a 7.5 MHz linear array transducer. Each testicle was examined separately by placing the transducer vertically. Images were analysed with specific software using the spot metering technique in four spots with a diameter of 1 cm on the same place of the image. At the same times, rectal, anal and scrotal surface temperatures were measured with a laser thermometer. Pixel intensity was lower with time (blacker, p < 0.0001), as a consequence of GnRH treatment (p < 0.0001). Differences between pixel intensities were significant starting 1 h after the first GnRH dose (p < 0.0001). Perineal temperature (33.9 ± 0.2°C) was not affected by treatment or time (p > 0.1). Rectal temperature was similar in both groups (p < 0.05) until 4 h after the beginning of the treatment (13:00 h). The differences between treatments increased since 4 h after the first dose of GnRH. Scrotal surface temperatures were not affected by treatment (p > 0.1). We concluded that multiple small GnRH doses trigger a rapid increase in testicular fluid content not accompanied by changes on scrotal surface temperature.

The stress response of frequently electroejaculated rams to electroejaculation: hormonal, physiological, biochemical, haematological and behavioural parameters.

Electroejaculation (EE) is a technique widely used to collect semen in ruminants, which produces a stress response with negative effects on animal welfare. The aim of this paper was to characterize the stress response during conventional EE in rams that have been frequently electroejaculated. Blood samples were collected since 20 min before and until 120 min after electroejaculating 10 rams. Electroejaculation affected hormone concentration, as cortisol increased, and testosterone decreased after EE. Heart and respiratory rate increased 10 min after EE. Several blood parameters, such as glycaemia, an increase in total protein and creatine kinase concentrations and a decrease in haematocrit, haemoglobin, red blood cell and alkaline phosphatase concentrations. The rams vocalized 13.8 ± 2.4 times, and the largest length of vocalizations during EE was associated with the numbers of pulses in which the rams ejaculated. In this paper, we provide a complete characterization of the stress response to EE in rams. We showed that although rams have been frequently electroejaculated, an important stress response including changes in respiratory rate, testosterone concentrations, haematological and biochemical parameters were observed, besides the changes in cortisol concentrations and heart rate, suggesting that rams were not habituated to EE. In addition, we described the main parameters of vocalizations and its relation with the moment of EE. The information displayed on the frequent use of EE in the rams should be considered in relation to the welfare implications.

Changes in the aerobic vaginal bacterial mucous load after treatment with intravaginal sponges in anoestrous ewes: effect of medroxiprogesterone acetate and antibiotic treatment use.

Intravaginal sponges (IS) impregnated with progestagens are widely used for oestrous synchronization in ewes. As progestogens depress the immuno response, the first aim was to determine whether medroxiprogesterone acetate (MAP) content affects the vaginal bacteria number (VBN) in IS-treated anoestrous ewes. The second aim was to compare the effectiveness of different antibiotic treatments to control the VBN increase caused by IS. In both experiments, IS were inserted during 14 days in anoestrous ewes. In the first, 11 ewes received commercial sponges (50 mg MAP), and 10 ewes received placebo sponges. For the second experiment, IS were inserted in three groups (n = 12/group), containing oxytetracycline im (20 mg/kg); injected into the sponge (0.02 mg), or control (no antibiotic). At sponge withdrawal, all ewes received 300 UI eCG. Mucous samples were collected from the vagina before sponge insertion, at sponge withdrawal, 24, 48 and 72 h later, and the VBN (colony-forming units per ml; CFU/ml) was counted after 48-h incubation. Medroxiprogesterone content did not affect VBN (log CFU/ml: 4.3 ± 0.2 vs 4.4 ± 0.2 with and without MAP, respectively). Bacterial number increased from 3.5 ± 0.2 at sponge insertion to 6.9 ± 0.1 at sponge withdrawal (p < 0.0001) and decreased the following day to 4.3 ± 0.2 (p < 0.0001). In the second experiment, VBN increased at sponge withdrawal (p < 0.0001) in all groups and decreased the following day (p < 0.0001). The CFU/ml at sponge withdrawal was lower in ewes treated with antibiotics (p < 0.0001), being even lower when local rather than systemic antibiotic was administered (log CFU/ml: 3.3 ± 1.8 vs 7.2 ± 1.8). The day of oestrous VBN was similar for all treatments and similar to that observed before sponge insertion. We concluded that MAP does not influence the increase in VBN, as the main effect is provoked by the sponge device itself, and local antibiotic treatment resulted in a lower bacterial growth than systemic treatments.

The ovulatory response of anoestrous goats exposed to the male effect in the subtropics is unrelated to their follicular diameter at male exposure.

This study was designed to determine whether the follicular diameter at the introduction of the bucks influences the ovarian response in does exposed to males during the anoestrous season in the subtropics. Bucks (n = 4) were subjected to 2.5 months of long days from November 1st to stimulate their sexual activity. On 29th March, one of the four treated males was joined with the females (n = 13), being exchanged with other males every 12 h, during 10 days. Oestrous behaviour was recorded twice daily. Ultrasound examinations of the ovaries were performed once daily from Day -7 to -1 and twice daily from Day 0 to 6. Follicles that ovulate were categorized according to the diameter at the moment when females were joined with males, as Small (<3.9 mm), Medium (4.0-5.9 mm) or Large (>6.0 mm). All females ovulated (13/13) and 12 came into oestrus during the first 5 days after exposure to males. The growth rate of the follicles increased after the introduction of the bucks from 1.1 ± 0.1 mm per day to 1.5 ± 0.1 mm per day (p < 0.05). The percentage of follicles from each category that ovulated did not differ (p > 0.05; Small 47.8%; Medium 34.8% and Large 17.4%). From follicles that ovulated, the growth rate of those that were Small at the moment of the introduction of the bucks was greater (2.1 ± 0.1 mm per day; p < 0.05) than that observed in those that were Medium (1.3 ± 0.1 mm per day) and Large follicles (1.1 ± 0.1 mm per day). In 12 does, the largest follicle present in the ovaries was growing when bucks were introduced. From these follicles, five finally ovulated and seven finally regressed. In conclusion, the follicular diameter at the introduction of the bucks is not related to the oestrous behaviour and ovulatory responding patterns in female goats exposed to sexually active bucks in the subtropics.

Short- and long-term effects of temporary early cow-calf separation or restricted suckling on well-being and performance in zebu cattle.

Information on weaning techniques in the tropics is scarce, particularly regarding the long-term effect of temporary early cow-calf separation or restricted suckling. Therefore, we studied the effects of these two handling practices on well-being and performance at 150 days postpartum in fifteen zebu cow-calf pairs randomly assigned to three treatments. Continuous suckling (CS) where calves remained with their dams from birth to weaning; restricted suckling (RS) calves were allowed to suckle 30 min/day from Day 34 until weaning at Day 150 and kept separated the rest of the time; temporary separation (TS) calves were separated for 72 h from their dams from Day 33 to 36 but remained with their dams the rest of the time. Blood samples and behavioral data were collected on Days 32-36 (1st period) and 149-153 (2nd period). In the 1st period, a greater percentage of RS and TS calves were observed close to the fence line (<10 m) that separated them from their dams (P < 0.0001) and vocalized more than CS calves (P < 0.0001), while in the 2nd period, RS calves had the highest cortisol concentration and vocalization rate (P < 0.05). Similarly, during the 1st period, a greater percentage of RS and TS cows were observed close to the fence line than CS cows (P < 0.0001), with TS cows vocalizing the most (P = 0.001). In the 2nd period, RS cows had greater cortisol concentration than TS (P = 0.037) and CS cows (P = 0.003). More TS and CS cows than RS were observed close to the fence line (P = 0.03 and P = 0.05). On Day 150, TS calves and cows vocalized more than RS and CS animals (P < 0.0001). Before calf-cow separation, 27 out of 45 cows were cycling (CS = 10; RS = 6; TS = 11). After separation, 12 of the remaining 18 cows resumed ovarian activity (CS = 3; RS = 5; TS = 4), and all cows were cycling after estrous synchronization treatment. The pregnancy rate was similar between CS, RS, and TS (60, 53, and 60% respectively). In conclusion, temporary separation increased calf distress response to definitive weaning even four months later, while restricted suckling seemed to reduce it.