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1.
Sixteen rams were used to quantify the effects of long days, imposed during late winter/early spring, with or without exogenous melatonin, on plasma testosterone concentrations and ram serving capacity. Rams were assigned to two groups: photoperiod‐treated rams (Artificial Photoperiod, AP; n = 8), exposed to 2 months of long days (16 hr of light/day) between 22 December and 22 February, and control rams (Natural Photoperiod, NP; n = 8). At the end of the long‐day period, AP rams were returned to the natural photoperiod, and each ram in the two groups either did (+M) or did not (‐M) receive three subcutaneous melatonin implants. Four groups were created as follows: AP+M (n = 4), AP‐M (n = 4), NP+M (n = 4) and NP‐M (n = 4). Thirty days after of the onset of photoperiodic treatment, AP rams (13.5 ± 2.8 ng/ml) had significantly (p < .05) lower testosterone levels than NP rams (36.7 ± 1.0), and similar differences were not apparent at the end of the photoperiod treatment. A month later, AP rams (24.3 ± 7.9) had higher (p < .10) testosterone levels than NP rams (13.1 ± 5.0), with no effect of melatonin treatment. Fifty days after melatonin implantations, rams were exposed for 20 min to three oestrous ewes. AP rams (2.50 ± 0.42) exhibited significantly (p < .05) more serves than did NP rams (1.11 ± 0.39), and melatonin treatment had no significant effect; however, the interaction between treatments was significant. Time to first serve was significantly (p < .05) shorter in AP (2.30 ± 1.20 min) than it was in NP rams (5.58 ± 0.68 min). In conclusion, exposure to 2 months of long days in late winter/early spring, with a return to natural day length of shorter duration, increased plasma testosterone concentrations and sexual performance in rams with or without exogenous melatonin. This particular management is an option if a non‐hormonal reproductive strategy is scheduled; yet, if the use of exogenous hormones is feasible, melatonin implants increase the mating efficiency of rams.  相似文献   

2.
Two groups of 24 Hampshire and 26 Suffolk purebred ewes each were used to study effects of cohabitation with cyclic white-faced (WF) ewes on estrous activity in June. Ewes lambed in January, February and March and had been isolated from mature rams since the previous fall breeding. From June 1 to July 2, treated (T) ewes were exposed to vasectomized rams and to 65 WF ewes; control (C) ewes were exposed only to vasectomized rams. Ovulation was assessed with biweekly serum progesterone assays; crayon marks were used to detect estrus. Daily observations of ram behavior were conducted to assess sexual activity of rams joined with T and C ewes. Cohabitation with WF ewes increased (P less than .01) ovulation percentages from 46% in C (42% for Hampshires and 50% for Suffolks) to 76% in T ewes (79% for Hampshires and 73% for Suffolks). Mating percentage also was increased (P less than .05) by cohabitation with WF ewes from 14% for C ewes to 30% for T ewes. Rams with T + WF ewes spent more (P less than .05) time checking ewes for estrus than did rams with C ewes. Hence, cohabitation with cycling WF ewes increased ovulation and mating percentages. Many acyclic T ewes first ovulated after 10 or more days of teasing, possibly due to increased ram contact in the presence of WF ewes.  相似文献   

3.

This study aimed to evaluate the effect of progesterone (P4) device reutilization in long and short protocols for transcervical timed artificial insemination (TAI) in Santa Inês ewes. A total of 275 multiparous lactating ewes were blocked according to body weight (BW, 49.1?±?7.3 means ± SE), body condition score (BCS, 2.9?±?0.4; scale of 1–5), and days postpartum (50?±?8.2 days), and allocated to one of the treatments. The treatments were arranged in a factorial design, in which the factor 1 was the P4 device type (new or a device of 0.3 g of P4 previously used by 11 days), and the factor 2 was the short or long TAI protocol (P4 device remained by 7 or 11 days, respectively). At device removal, all ewes received 300 IU eCG and 6.70 mg of Dinoprost tromethamine. After TAI protocol, ewes remained with ram by 21 days. There was no interaction between factors in any variables. Ewes that received a new P4 device delayed (P?=?0.05) to show estrus compared with ewes receiving a previously used P4 device, but it did not affect pregnancy rate. The long protocol tended to increase pregnancy rate compared with short protocol (33% vs. 24%, respectively; P?=?0.07). However, the pregnancy rate at the end of reproductive period was similar in both groups (about 84%). Thus, the use of long protocols tended to improve reproductive performance, and the reused P4 device did not affect pregnancy rate.

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4.
The GMM sheep is a carrier of Booroola fecundity (FecB) gene, which produces the twins and triplets in one lambing. The homozygous carrier GMM (FecBBB), non‐carrier GMM and Malpura (FecB++) ewes were synchronized by progesterone sponges, and the plasma progesterone concentration was measured by RIA. The results showed that the progesterone concentration did not differ significantly (p > .05) in homozygous carrier GMM (5.74 ± 1.2 ng/ml), non‐carrier GMM (5.42 ± 1.4 ng/ml) and non‐carrier Malpura ewes (5.67 ± 1.5 ng/ml). Further, quantitative expression of BMP factors/receptors and SMAD signalling genes were analysed in the ovaries of sheep by qRT‐PCR. The study showed that the expression of BMP2 was slightly higher (p > .05) in carrier GMM than that of non‐carrier GMM, but it was almost similar to Malpura ewes. Expression of BMP4 and BMP7 was significantly higher (p < .001; p < .05) in carrier GMM than that of non‐carrier GMM and Malpura ewes. Although BMP6 expression was higher (p > .05) in carrier GMM than that of non‐carrier GMM, but lower (p > .05) than the Malpura ewes. Expression of BMP15 (p < .05), GDF5 (p < .01) and GDF9 (p < .05) was significantly higher in carrier GMM than non‐carrier GMM ewes. Surprisingly, BMPR1B expression was significantly higher (p < .001) in non‐carrier GMM and Malpura than the carrier GMM ewes, while TGFβRI did not differ significantly (p > .05) among both GMM genotypes. On the other hand, expression of BMPR1A (p > .05) and BMPRII (p < .05) was higher in carrier GMM than the non‐carrier GMM, but significantly lower (p < .001) than the Malpura ewes. It was interesting to note that the expression of SMAD1 (p > .05), SMAD2 (p < .001), SMAD3 (p < .05), SMAD4 (p < .001), SMAD5 (p < .001) and SMAD8 (p < .001) was lower in the carrier GMM than that of non‐carrier GMM ewes. It is concluded that the FecB mutation alters the expression of BMPR1B and SMAD signalling genes in the ovaries of homozygous carrier GMM ewes.  相似文献   

5.
This study assessed the changes of plasma vitamin A, E, and C and the lipid peroxidation status of sheep during breeding and pregnancy under drought conditions. The study was conducted on 105 cross-bred fat tailed ewes, 3–5 years old with body condition scores (BCS) of 2.5 to 3.5. The ewes were grazing on medium-to-low quality forages during summer and low quality forages within the succeeding months and had ad libitum access to a mixture of alfalfa hay (40%) and wheat straw (60%) in the afternoons. From 3 weeks before breeding till 1 month after the introduction of rams, 300 g of barley grain/head/day was offered to the ewes and then the supplemental grain was reduced to 100 g/head/day. For better synchronization of estrus cycles in ewes, they were isolated from the rams for at least 2 months and then kept in close proximity of the rams for 1 week before the introduction of the rams to the ewe flock. Then, whole blood samples were collected on days 1, 7, 21, and 120 after ram introduction. Vitamins A, E, and C were measured in plasma. Malondialdehyde (MDA) was measured in the hemolysate as a biomarker of lipid peroxidation. Plasma progesterone (P4) was measured in the samples of day 120 for assessing pregnancy status of the ewes. Vitamins A and C showed continuous and significant declines (P < 0.05) through days 1 to 120. Vitamin E declined only during the first 21 days of the study and remained almost constant till day 120. MDA concentration increased significantly at day 21. An elevated concentration of MDA was also detected at day 120. The difference between days 21 and 120 was not significant (P > 0.05). A positive correlation between vitamins E and C was detected at day 120 (r = 0.349, P < 0.01). Age and BCS did not affect the patterns of changes. Assuming that the ewes with P4 concentrations ≥2.5 ng/ml were pregnant, 95 out of 105 ewes (90.5%) were pregnant at day 120 of the study. Under the conditions of the present study with medium-to-low quality pastures as the main sources of feed, ewes of various ages and body conditions may suffer from oxidative stress during breeding and pregnancy.  相似文献   

6.
This study examined the feasibility of transcervical embryo recovery after the hormonal treatment to induce cervical dilation, following the 7‐day oestrous synchronization protocol in multiparous Santa Inês ewes. A total of 23 cyclic ewes received two doses of 37.5 μg of d‐cloprostenol by latero‐vulvar route 7 days apart. After the second injection of d‐cloprostenol, the ewes were checked for oestrus (every 12 hr) and then mated by fertile rams throughout the oestrous period. All ewes received 37.5 μg of d‐cloprostenol (latero‐vulvar) and 1 mg of oestradiol benzoate by either intramuscular (EBim group; n = 12) or intravaginal (EBivg group; n = 11) route 16 hr before embryo flushing. Twenty minutes before the flushing, 50 IU of oxytocin were administered intravenously. The oestrous response (i.e., the percentage of ewes that showed signs of oestrous behaviour after the second d‐cloprostenol injection) was 91.3% (21/23). The proportion of successfully penetrated ewes (81.8% compared with 80.0%), the mean duration of embryo flushing (24.7 ± 2.0 min compared 26.2 ± 1.9 min), the flushing fluid recovery rate (94.8 ± 1.3% compared with 91.0 ± 2.9%) and the average number of structures recovered per ewe (0.5 ± 0.4 compared with 0.8 ± 0.4) did not vary (p > 0.05) between the EBim and EBivg groups. Viable embryos were recovered from 41.2% (7/17) of successfully penetrated ewes. It can be concluded that nonsurgical (i.e., transcervical) embryo collection can be performed in oestrous‐synchronized Santa Inês ewes pretreated with d‐cloprostenol, oxytocin and oestradiol benzoate, with the latter hormone administered by either the intramuscular or intravaginal route.  相似文献   

7.
In sheep, access to receptive females is affected by dominance relationships. The aim of the first experiment was to determine how the presence of high- or low-ranking rams affects sexual behavior of medium-ranked rams toward non-estrual ewes in pen tests. A complementary objective was to determine whether the presence of 1 or 2 rams has stronger effects. Social rank of 13 rams was determined using the food competition test. The number of courtship behaviors, mounts, and ejaculations was recorded in pen tests with non-estrual restrained ewes. In the first experiment, medium-ranked rams were subjected to 5 tests with: (1) the ewe alone, (2) the ewe and 1 restrained tied high-ranked ram, (3) the ewe and 2 restrained tied high-ranked rams, (4) the ewe and 1 restrained tied low-ranked ram, and (5) the ewe and 2 restrained tied low-ranked rams. The number of high- or low-ranked rams (1 or 2) present in the tests did not affect the results. There were no differences on courtship behaviors, but the number of mounts and mounts with ejaculation was greater when low-ranked rams were present. In a second experiment, it was determined whether the presence of medium- or low-ranked rams stimulates sexual behavior of high-ranked rams. The high-ranked rams were tested with: (1) the ewe alone, (2) the ewe and 1 restrained tied medium-ranked ram, and (3) the ewe and 1 restrained tied low-ranked ram. No differences were recorded in relation to presence of other rams during the tests. It was concluded that the presence of low-ranked rams stimulates sexual behavior of medium-ranked rams toward non-estrual ewes in pen tests. This effect was not related with the number of rams included in the test. The presence of medium- or low-ranked rams did not alter the sexual behavior of high-ranked rams toward non-estrual ewes.  相似文献   

8.
The aim of this study was to evaluate the effects of ram introduction after the second prostaglandin F2α (PG F2α) injection on day 11 on the secretion characteristics of pre‐ovulatory LH surge of fat‐tailed ewes. Multiparous Morkaraman ewes (n=12) were divided into three groups by balancing the groups for liveweight (BW) and body condition score (BCS). On the day of second PGF2α injection (0 h), performance tested rams (n=2) were either introduced to the ewes at 0 h (ram 0 group, n=4) or at 18 h (ram 18 group, n=4) or were not introduced (control group, n=4). Blood samples were collected at 6, 18, 42, 48, 56, 62, 66, 70, 74, 78 and 90 h for the determination of pre‐ovulatory LH surge. BCS and BW during the experimental period were 2.2 ± 0.2 units and 50.9 ± 2.3 kg, 2.4 ± 0.4 units and 49.2 ± 6.2 kg, 2.1 ± 0.3 units and 45.9 ± 4.4 kg, respectively for the ram 0, ram 18 and control groups (p > 0.05). No significant difference was observed in LH surge characteristics for the experimental groups. Peak LH concentrations were also not different between groups (p > 0.05) and they were 12.2 ± 8.3, 29.1 ± 9.9 and 15.8 ± 9.5 μg/l for the ram 0, ram 18 and control groups, respectively. There was, however, a significant correlation between peak LH concentrations and BCS (p < 0.05, R2=0.373). In conclusion, it appears that, compared with ram introduction, variability in body condition of the ewe has much pronounced effect on the amount of LH secreted after the usage of two PGF2α injections (11 days apart) as a tool for oestrus synchronization.  相似文献   

9.
The effect of GnRH administration on superovulatory response of ewes treated with equine chorionic gonadotrophin (eCG) in breeding and nonbreeding seasons and the contribution of laparoscopic insemination to the improvement of fertilization and embryo recovery were investigated. Twenty-four nonpregnant Awassi ewes of 3–4 years of age were randomly allocated into two groups (n = 12). Each ewe was treated with a progesterone impregnated intravaginal sponge for 12 days. The following superovulation treatment was used: ewes of group 1 received 1,200 IU of eCG once as an intramuscular injection 48 h prior to sponge withdrawal; ewes of group 2 also received 1,200 IU of eCG once as an intramuscular injection, 48 h prior to sponge withdrawal and after 24 h of sponge removal. Ewes were injected with 80 μg of GnRH. Ewes of groups 1 and 2 were further subdivided into four equal groups (n = 6). Subgroups A and C (superovulated with eCG and eCG plus GnRH, respectively) were mated naturally at least two times with Awassi rams of proven fertility at 8-h intervals. Subgroups B and D (same as A and C) had intrauterine insemination at 44–46 h after sponge removal, under laparoscopic visualization of uterine horns, depositing 1 ml of diluted semen containing 100 × 106 motile sperm in the distal portion of each uterine horn. Ovarian response was assessed by determining the number of corpora lutea by laparoscopy at day 6 after mating. Embryo recovery was performed by using a semi-laparoscopic flushing procedure in both uterine horns. Results of the present study showed that ewes treated in breeding season with eCG plus GnRH has a higher number (P < 0.05) of corpora lutea than eCG alone as 7.33 ± 0.54 and 4.33 ± 0.39, respectively. There was no significant difference in the number of corpora lutea in nonbreeding season when ewes treated with eCG and eCG plus GnRH. The number of unovulated follicles was significantly higher (P < 0.05) in eCG treated ewes than in ewes treated with eCG plus GnRH, both in the breeding and nonbreeding seasons. The number of recovered embryos from ewes treated with eCG plus GnRH and eCG differ significantly (P < 0.05) as 4.32 ± 0.56 and 1.06 ± 0.26, respectively, in the breeding seasons. No significant difference was observed when these hormones used for superovulation in the nonbreeding season. A higher number of unfertilized ova (P < 0.05) was observed in ewes when naturally inseminated than in ewes inseminated using the intrauterine laparoscopic technique. Higher rate of embryo recovery (P < 0.05) was achieved when ewes were inseminated via intrauterine (4.66 ± 0.66) compared with ewes naturally mated (2.16 ± 0.74). The fertilization rate in ewes inseminated intrauterine using laparoscopic techniques and naturally mated were 91.5% and 44.8%, respectively. Fertilization failure in ewes inseminated intrauterine using laparoscopic techniques and naturally mated were 8.4% and 55.2%, respectively. It could be concluded that administration of GnRH 24 h after sponge removal increased ovulation rate of Awassi ewes treated with eCG for superovulation in the breeding season. The use of eCG to induce superovulation in Awassi ewes combined with laparoscopic intrauterine insemination increases the fertilization rate.  相似文献   

10.
The study aimed to investigate the effects of vitamin E injection for the prevention of transport stress on ewes. Kivircik ewes (2–3 years old, n = 24) were randomly separated into three groups; G1 (Control) and G2 treated with 14 ml. saline as the placebo, G3 treated with 2100 IU/ind. DL-alpha-tocopherol acetate prior to transport. G2 and G3 were transported at 80 km/h for 4 h on a truck. Serum samples were obtained before (T0) and after (T1) transport. Serum cortisol, catalase, IgG, ceruloplasmin, C-reactive protein, complement component 4, interleukin-1 beta, tumour necrosis factor-alpha, glutathione peroxidase (GPx), superoxide dismutase, malondialdehyde analyses performed by ELISA, and serum alpha-tocopherol concentrations were evaluated by HPLC-UV. Wilcoxon and Kruskal–Wallis tests were used for statistical assessments (p < 0.05). Alpha-tocopherol concentrations were founded 1.22 ± 0.82, 0.27 ± 0.14 and 0.14 ± 0.07 µmol/L, respectively, in G1, G2 and G3 at T1. Alpha-tocopherol concentration decreased significantly in G2 between T0 and T1. GPx concentrations were increased twofold in G2 and G3 between T0 and T1 (p < 0.01). As a result, G2 alpha-tocopherol concentrations decreased but, the stress and oxidative parameters tested in this study were not affected by treating 2100 IU/ind. DL-alpha-tocopherol acetate before transport.  相似文献   

11.
Rheotaxis of sperm using a microfluidic device was explored in human, mice and bull. However, the rheotaxis of ram sperm and its role in fertility are unknown. Herein, we described the sperm rheotaxis in ram using microfluidic devices and focused on rheotaxis as potential markers of in vivo fertility. Computer-assisted sperm analysis (CASA) with controlled flow velocity was used to explore the kinematic parameters of sperm, total motility and positive rheotaxis (PR). The percentage of PR was defined as the number of PR sperm cells over the number of motile sperm cells. Then, according to the percentage of PR sperm, rams were classified into two groups; sperm with ≥40% PR and <40% PR, although the two ram groups showed similar total motility and kinematic values of sperm evaluated by CASA (p > .05). Two groups of rams mated one hundred thirty ewes naturally (10 ewes/ram). In the results, the pregnancy rate was higher in ≥40% PR (94.4%) than in <40% PR (42.5%, p < .05) after natural mating. Besides, the pregnancy loss was higher in <40% PR (33.3%) than in >40% PR group (8.1%, p < .05). In conclusion, the PR examination in semen can contribute to evaluate the reproductive performance of ram that will provide valuable insights into the semen evaluation.  相似文献   

12.
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.  相似文献   

13.
Two groups of purebred ewes (A and B), each consisting of 25 Dorsets and 25 Hampshires, were used to study effects of ewe breed and ram exposure on ovulation and estrus in May and June. Ewes lambed in January and February and were isolated from mature rams for at least 5 mo. From May 8 to June 11 (Period 1), Group A ewes were penned with vasectomized rams fitted with marking harnesses and Group B ewes were isolated from rams. From June 11 to July 13 (Period 2), rams were placed with Group B ewes and Group A ewes were isolated from rams. Ovulation was monitored by biweekly serum progesterone assays and crayon marks were used to detect estrus. For Group A ewes in Period 1, more Dorsets ovulated (96%) than did Hampshires (72%), and of ewes that ovulated, more Dorsets mated (83 vs 28%). Fifty-five percent of Dorsets, but only 20% of Hampshires, appeared to have been spontaneously cycling at the start of the experiment. Of ewes mated in Period 1, more Dorsets than Hampshires continued to cycle during Period 2 (65 vs 0%). For Group B ewes in Period 1, 44% of Dorsets, but only 8% of Hampshires, ovulated in the absence of rams. In Period 2, 92% of Dorsets and 84% of Hampshires ovulated. Of ewes that ovulated, more Dorset ewes mated (78 vs 52%). Of ewes that mated, more Dorsets appeared to be cycling spontaneously at ram introduction (39 vs 0%). Throughout the study, 24% of Dorsets, but no Hampshires, cycled continuously.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

14.
There is a paucity of information on the relationships of testicular morphology, echotextural attributes, and blood flow dynamics with pubertal development of rams raised in a subtropical climate. Forty‐five Dorper rams (24 rams aged 8–11 months and 21 rams aged 12–24 months) were examined using a portable ultrasound scanner connected to a 7.5‐MHz transducer. Computer‐assisted analyses of testicular ultrasonograms utilized commercially available Image ProPlus® analytical software. Spectral Doppler scans of testicular arteries were performed immediately after scrotal (B‐mode) ultrasonography to determine peak systolic velocity (PSV), end‐diastolic velocity (EDV), resistive index (RI = [PSV?EDV]/PSV), and pulsatility index (PI = [SPV–EDV]/mean velocity) of the blood vessels. The length of the testes (9.7 ± 0.3 compared with 9.0 ± 0.2 cm) and scrotal circumference (33.3 ± 0.5 compared with 31.8 ± 0.4 cm) were greater (p < 0.05) but testicular depth (4.5 ± 0.1  compared with 4.9 ± 0.08 cm) was less (p < 0.05) in sexually mature compared with peripubertal rams. [Corrections added on 9 Jan 2019 after initial online publication: The testicular size values in the sentence were corrected.] There were no differences (p > 0.05) between the two age groups of Dorper rams in blood flow indices of testicular arteries. Mean numerical pixel values (100.5 ± 4.1 compared with 89.2 ± 4.8) and pixel heterogeneity (25.6 ± 0.6 compared with 23.6 ± 0.5) of testicular parenchyma were greater (p < 0.05) in peripubertal than in postpubertal rams. Semen volume was negatively correlated with PI of testicular arteries (r = ?0.57, p = 0.04). In summary, the attainment of sexual maturity in the rams of the present study was associated with significant changes in testicular length and depth, scrotal circumference, and parenchymal echogenicity/hetrogeneity but not in testicular volume and blood perfusion rates. Testicular artery PI can be used to predict the volume of ejaculate in rams.  相似文献   

15.
Two experiments were carried out to determine the efficiency of supplementation of ram semen extender with caffeine on chilled storage and frozen capacity of spermatozoa. In the first experiment, eighty ejaculates were collected by an artificial vagina from five adult Barki rams, aged 2–3 years and weighted 45.0 ± 2.0 kg throughout the experimental period (January to February 2017). The ejaculates were pooled and diluted (1:10) with tris‐citric egg yolk extender and were split into five groups. Group 1 served as control, whereas groups 2‐5 were supplemented with 0.1, 0.2, 0.3 and 0.4 mM caffeine. All diluted semen specimens were evaluated for physical characteristics immediately after dilution (T0) and throughout preservation period of 48 hr at 4°C. Simultaneously, oxidative stress and indices such as total antioxidant capacity (TAC), malondialdehyde concentrations (MDA) and alkaline transaminase (AKP) concentrations and value of resazurin reduction test (RRT) were determined. In the second experiment, the raw pooled ejaculates were diluted (1:10) with glycerolated tris‐citric egg yolk extender, receiving the previously mentioned caffeine levels. The post‐thaw assessment of cryopreserved spermatozoa, in all groups, was conducted by a computer‐assisted sperm analysis (CASA) system. The results revealed that adding caffeine to ram semen extender at low (0.1 mM) or medium (0.2 mM) levels had positive impact on both physical characteristics of ram sperm and the enzymatic activities compared to the other semen groups. Caffeine supplementation also enhanced post‐thaw sperm dynamics, which implies its potential as an exogenous antioxidant supplement.  相似文献   

16.
The objectives for this study were to 1) determine the relationship between sexual performance class and lambs sired in a competitive mating environment, and 2) determine whether the male-oriented ram test is valid. Fifteen 2- to 3-yr-old whitefaced rams classified as female-oriented, with high or low sexual performance, or classified as male-oriented were used in a multiple-sire breeding arrangement. Five groups of approximately 200 ewes each were exposed for 21 d to 3 rams per group consisting of 1 ram from each class. Rams were blocked for sexual class, and those with close genetic relationship were assigned to different pens. Genomic DNA was prepared from blood collected from 15 rams, 934 ewes, and 1,757 lambs. Up to 4 microsatellite markers were used to determine a lamb's sire. Of 884 ewes with identifiable lambs (known sires), 178 ewes had single lambs, 408 had multiples sired by 1 ram, and 298 had multiples sired by more than 1 ram. The sexual partner preference test used to identify male-oriented rams did not absolutely reflect their sexual performance during competitive breeding. In contrast to only mounting and servicing males in preference tests before breeding, male-oriented rams sired 480 lambs from 330 ewes. Serving capacity tests predicted sexual performance of high and low sexual performance rams. High performance rams impregnated more ewes (499 vs. 258; P < 0.05) and sired more lambs (756 vs. 357; P < 0.05) than did low performance rams, respectively. Low performance and male-oriented rams did not differ for ewes impregnated or lambs sired. We conclude that 1) sexual partner preference tests used to classify male-oriented rams were not absolute in reflecting their breeding performance in a competitive breeding environment; 2) serving capacity tests predicted that high performance rams would breed more ewes than low performance rams and sire more lambs than either low performance or male-oriented rams; and 3) under the conditions of this study, low performance and male-oriented rams did not have an adverse impact on the overall breeding outcome. Combined, low performance and male-oriented rams sired 81 more lambs than did high performance rams, but this required twice as many rams to obtain approximately equal breeding results. Therefore, we suggest that serving capacity tests should be used to select high performance rams, reduce number of rams with marginal sexual performance, and make decisions on ram numbers needed.  相似文献   

17.
The objective of this study was to determine whether season and total rainfall during the breeding season, sheep parity, and/or litter size affect the interval from the introduction of rams to estrus (IRE) in hair Saint Croix sheep in northeastern Mexico. An analysis was made of 874 services performed during 9 years, introducing the rams into the sheep flock after an isolation period of 60 days during the postpartum period. Estrus was recorded twice daily during 35 days. Year and season influenced significantly on the interval between ram introduction and estrus length (P < 0.01). Winter IRE length (7.9 ± 0.1 days) was shorter than in the other three seasons (11.1 ± 0.2, 11.1 ± 0.1, and 16.2 ± 0.2 days in summer, autumn, and spring, respectively) (P < 0.01). An interaction was observed between rainfall and season, then by rainfall between 0 and 100 mm, IRE was shorter (P < 0.05) in winter (6.8 ± 0.3 days), and by rainfall between 100 and 199 mm, IRE was shorter (P < 0.05) in autumn (10.2 ± 0.5 days); however, when rainfall was beyond 200 mm, IRE length was shorter (P < 0.01) in summer (4.8 ± 0.5 days) than in autumn (14.5 ± 0.3 days). The IRE length was also longer in first lambing ewes (P < 0.05) and was not affected by litter size. In the present study, several factors, including the breeding season, rainfall and parity, directly influenced the interval between the male introduction and the onset of estrus by Saint Croix hair sheep.  相似文献   

18.
The goal of this study was to establish Magnetic resonance imaging (MRI) reference ranges for spinal measurements in normal dogs. Forty dogs (1–10 kg, 11–20 kg, 21–30 kg, > 30 kg; 10 dogs per category) underwent spinal MRI. Measurements were performed on sagittal T2‐W images at the level of the 4th thoracic vertebra (T4), the 9th thoracic vertebra (T9) and the 3rd lumbar vertebra (L3). Spinal canal diameter (mm) ranged from 6.07 ± 0.63 (1–10 kg) to 8.27 ± 1.15 (> 30 kg) at the level of T4; 6.55 ± 0.61 (1–10 kg) to 9.04 ± 1.26 (> 30 kg) at the level of T9; and 6.80 (6.47–7.00; 1–10 kg) to 9.00 (7.90–9.73; > 30 kg) at the level of L3. There were significant differences (P < 0.05) in spinal canal diameter between groups. Mean spinal cord diameter (mm) ranged from 4.46 ± 0.51 (11–20 kg) to 4.70 ± 0.35 (1–10 kg) at the level of T4; 4.41 ± 0.50 (> 30 kg) to 4.85 ± 0.57 (1–10 kg) at the level of T9; and 4.52 ± 0.51 (> 30 kg) to 5.14 ± 0.68 (1–10 kg) at the level of L3. There were no significant differences in spinal cord diameter between groups. Spinal cord‐to‐spinal canal ratio varied significantly, ranging from 0.51 ± 0.08 (> 30 kg at L3) to 0.78 (0.69–0.80; 1–10 kg at T4) (P < 0.05). These findings are important when using MRI to evaluate patients with suspected diffuse spinal cord disease.  相似文献   

19.
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.  相似文献   

20.
This study outlines a new approach to reproductive tract treatment using ozone foam spray for certain ovine obstetrical problems, such as retained foetal membranes and possible uterine infections following obstetric assistance (OA), in comparison with classical antibiotics treatments. The study was conducted on 256 ewes from 11 sheep farms in north‐western Croatia. A total of 139 ewes were diagnosed with dystocia (DT) and 49 with retention of placenta (RP). Ewes with RP were treated either with ozone foam spray (Riger spray G; Novagen®) applied into the body of the uterus for 2–3 s (first or RPO group; n = 24) or with two foaming, intrauterine tablets of oxytetracycline hydrochloride (Geomycin® F) (second or RPA group; n = 25). The third and fourth groups consisted of ewes that received OA for dystocia (including ringwomb, foetal oversize and assistance of abnormal position and posture). The third group (DTO; n = 70) was treated with ozone foam spray, while ewes in fourth group (DTA; n = 69) were treated with antibiotics. The ewes in the control group (CTL) with physiological puerperium were randomly selected (n = 70) from all herds. Transrectal ultrasonography (transversal diameter of uterine horns) was used for the control of uterus regression on days 2 and 25 after parturition. There was a difference in transversal uterine horn diameter in the RP groups, that is RPO and RPA (5.40 ± 0.53 cm vs. 5.43 ± 0.40 cm), ewes with dystocia, that is DTO and DTA (5.37 ± 0.49 cm vs. 5.54 ± 0.60 cm) and ewes from the CTL group (4.98 ± 0.35 cm) one day after parturition. Average transversal uterine diameter of all groups at day 25 post‐partum was 1.80 ± 0.15 cm. The intrauterine ozone treatment in ewes with RP and after manual obstetrics attained similar results to spontaneously delivered ewes (CTL group), showed as the physiological regression of the uterus with a similar transversal diameter without the presence of lochia in the uterine lumen, indicating that this could be a novel potential alternative therapy.  相似文献   

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