首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 46 毫秒
1.
Feedlot growth performance and carcass characteristics were examined in 96 crossbred heifers of continental breeding. Heifers were assigned to four treatment groups: intact control, sham ovariectomized, ovariectomized, and ovarian autografted. Ovarian autografted heifers were bilaterally ovariectomized via a left flank incision and one ovary was bisected sagittally and implanted in the musculature of the flank. Animals were fed a diet based on corn silage and were slaughtered at a weight of about 450 kg. There was no effect of treatment on feedlot performance or objectively measured carcass traits. However, carcasses of ovariectomized and ovarian autografted heifers had lower maturity scores than carcasses of the intact and sham-ovariectomy heifers. Blood samples were collected monthly throughout the study. Progesterone concentrations in these samples indicated that approximately 20% of the ovarian autografted heifers exhibited ovarian cyclicity. Examination of the transplanted ovaries at slaughter indicated that approximately 20% of the transplanted ovaries were resorbed. Cavitated, fluid-filled, thick-walled structures that were considered to be luteinized follicles were the most prominent structures found on the transplanted ovary; these were found in one-third of the ovarian autografted heifers. These results indicate that an ovary transplanted to the musculature can remain viable; however, its physiological function is disrupted and it does not affect rate or efficiency of gain or carcass composition compared to ovariectomized heifers.  相似文献   

2.
This study describes the morphological and morphometrical changes associated with prepubertal ovarian development in the Antarctic minke whale (Balaenoptera bonaerensis). Ovaries were harvested from 94 immature minke whales caught in the Antarctic Ocean during the summer feeding season (December-March). Notable differences in ovarian size and morphology were found among animals. Up to 10 folds difference in ovarian weight was found among prepubertal whales of similar body size. During the prepubertal period, ovaries grew slowly and approximately doubled their weight. The morphologies of right and left ovaries were almost identical while the growth of the ovary appears to occur preferentially on the right side. The most striking morphological feature was numerous small antral follicles less than 5 mm in diameter found in ovaries of younger immature whales. The occurrence of these ovaries was highest in whales less than 6 m long and gradually decreased as body length increased. In larger whales, the occurrence of ovaries with a smaller number of follicles up to 10 mm and thick tunica albuginea increased. Thus, the ovary of the Antarctic minke whale experiences bursts of small follicular development during the early prepubertal period before becoming a more developed ovary with fewer but larger follicles, and thick tunica albuginea.  相似文献   

3.
Twelve heifers were exposed to either a Colorado infectious bovine rhinotracheitis (IBR) virus isolate or an Iowa IBR isolate obtained from a bovine respiratory disease outbreak. All inoculations were made on the day after the heifers had been in estrus and bred by an IBR virus-negative bull. Pairs of heifers were inoculated with each virus isolate intravenously, intramuscularly or exposed by aerosol. The heifers were killed 11-15 days after inoculation and their reproductive tracts and ovaries subjected to virological and pathological study. Virus was isolated from the ovaries of all 4 heifers inoculated intravenously and from 3 of the 4 heifers inoculated intramuscularly, but not from the ovaries of heifers exposed by aerosol. Virus isolations and lesions were, with only 1 exception, confined to the ovary containing the corpus luteum. In ovaries from which IBR virus was isolated, lesions in the corpus luteum ranged from focal necrosis and infiltration of mononuclear cells to diffuse hemorrhage and necrosis. Most of these ovaries also had necrotic follicles and a diffuse mononuclear cell accumulation in the stroma. Lesions were not found in ovaries from which IBR virus was not isolated. It was concluded that lesions are readily induced in the ovaries of post-estrus heifers as a result of hematogenous spread of IBR virus and suggest that the differences in lesion development observed with the 3 routes are related to whether or not a viremia occurred.  相似文献   

4.
Objective To determine the value of peripheral blood concentrations of cortisol, creatine phosphokinase (CPK), aspartate aminotransferase (AST), non‐esterified fatty acids (NEFAs) and haptoglobin as indicators of welfare in Brahman heifers spayed by either the Willis dropped ovary technique (WDOT) or the flank laparotomy method. Design A total of 24, 2‐year‐old Brahman heifers were allocated to: crush (head‐bail) restraint alone (Control, n = 5); crush restraint and ear‐punch (Ear‐punch, n = 5); crush restraint, WDOT spay and ear‐punch (WDOT, n = 9); or crush restraint, elecrtoimmobilisation, flank spay and ear‐punch (Flank; n = 5). Cattle were blood sampled frequently to 8 h, and then daily to day 4 and were monitored to 42 days post‐procedure. Peripheral blood concentrations of bound and unbound cortisol, CPK, AST, NEFAs and haptoglobin were determined. Results Concentrations of plasma bound cortisol peaked in the spayed heifers 3–4 h post‐procedure; values in the Flank (1603 nmol/L) and WDOT (1290 nmol/L) groups were similar and significantly greater (P < 0.05) than in the Controls (519 nmol/L). Flank heifers had elevated plasma haptoglobin levels to day 4 postprocedure. Liveweights were significantly lower in the spayed compared with the Control heifers at 21 and 42 days post‐procedure, with liveweight gains also significantly reduced at day 21. Conclusions Bound cortisol responses in spayed heifers were elevated to 6 h post‐procedure and similar in WDOT‐ and flank‐spayed animals, indicating comparable levels of pain and stress. An inflammatory response, indicated by haptoglobin concentrations, was sustained for longer in Flank than in WDOT spayed heifers, suggesting longer‐lasting adverse effects on welfare from flank spaying than WDOT spaying.  相似文献   

5.
The effects of administering hCG on subsequent ovarian structure dynamics and concentrations of progesterone in prepubertal heifers were evaluated. Forty-seven purebred Angus heifers were assigned randomly to 1 of 3 treatments: 1) 100 μg of injection of GnRH (GnRH; n = 16); 2) 1,000 IU injection of hCG (H1000; n = 16); and 3) 500-IU injection of hCG (H500; n = 15). From d -1 to 9 relative to treatment (d 0), daily blood samples were collected to determine concentrations of progesterone and ovaries of each heifer were examined daily by transrectal ultrasonography. Diameter of all follicles ≥ 4 mm and all luteal structures were mapped. Disappearance of the largest follicle occurred within 2 d in a greater percentage (P < 0.05) of all heifers in the H1000 treatment (87.5%) compared with GnRH heifers (43.8%), whereas H500 heifers (73.7%) were intermediate. A new luteal structure formed after follicle disappearance in a greater (P < 0.05) percentage of all heifers treated with H1000 (87.5%) and H500 (73.7%) heifers compared with that in GnRH-treated heifers (18.8%). The largest follicle present in ovaries of H1000 and H500 heifers was smaller (P < 0.05) than that of GnRH heifers from d 2 to 5. Heifers treated with H1000 (1.72 ± 0.19 ng/mL) had peak concentrations of progesterone on d 6 that were greater (P < 0.05) than H500 heifers (1.34 ± 0.20 ng/mL), which were greater than heifers treated with GnRH (0.31 ± 0.19 ng/mL). The mean volume of luteal tissue was greater (P < 0.05) in H1000 heifers (1.54 ± 0.15 cm(3)) than in H500 heifers (1.15 ± 0.15 cm(3)), which was greater (P < 0.05) than in heifers treated with GnRH (0.23 ± 0.15 cm(3)). We conclude that hCG was more effective than GnRH in its ability to cause disappearance of the largest follicle, increase volume of luteal tissue in the subsequent developing luteal structures, and increase concentrations of progesterone in prepubertal heifers. In addition, hCG seems to be more effective when administered at 1,000 IU than at 500 IU.  相似文献   

6.
The size of the ovary varies substantially among cattle. This variation may influence the potential of the ovary to produce follicles. In the present study, we examined whether a relationship exists between the weight of the ovary and the number of antral follicles >or=1 mm. Paired ovaries were obtained from Holstein x Japanese Black F1 heifers. Follicles were classified into three size categories (small: 1.0-<5.0 mm, medium: 5.0-<8.5 mm and large: >or=8.5 mm), and the number of follicles in each category was recorded. Large variations in the weight of ovaries and the number of follicles were observed among animals. Significant positive correlations (r>or=0.4, P<0.001) were found between the weight of intact ovaries and the number of follicles in all three categories for the ovary contralateral to CL (OCC) and in the small follicles for the ovary ipsilateral to CL (OIC). Significant positive correlations (r>0.4, P<0.0001) were also observed between the weight of ovaries devoid of CL and follicles and the number of small and medium follicles in both OIC and OCC, indicating that the correlation is not due to the increase in ovarian weight associated with the increase in follicular number. Paired ovaries contained a similar number of small and medium follicles, and significant positive correlations were observed between them (r>0.6, P<0.0001). There were significant positive correlations between the weight of OCC and the number of small and medium follicles in paired ovaries (r>0.4, P<0.0001). These results suggest that 1) the weight of an ovary reflects the potential of the ovary to produce antral follicles, and 2) a rough estimation of follicular population might be possible by using the weight of the ovary contralateral to CL in heifers.  相似文献   

7.
Objective To determine morbidity and mortality rates in yearling heifers spayed by two methods under commercial conditions in northern Australia. Design In study 1,600 Brahman heifers were allocated to one of three treatments: physical restraint and ear-tagging (Control); physical restraint, ovariectomy by the Willis dropped ovary technique, ear-tagging and ear-marking (WDOT); or electroimmobilisation, ovariectomy via flank incision, ear-tagging and ear-marking (Flank). Heifers were monitored post spaying. Mortalities occurred at unanticipated times, so study 2 investigated their timing and cause in similar WDOT-spayed heifers (n = 574). Results In study 1, morbidity on the day of spaying was 6.0% in the Flank and 2.7% in the WDOT group (not statistically different). Spayed heifers showed behaviours indicative of acute pain/discomfort in the 6 h post spaying. Body weights and gains were significantly lower in the spayed compared with control heifers at days 21 and 42, and 5% of flank wounds were not healed at day 42. Mortalities were 0%, 1.5% and 2.5%, respectively, for Control, WDOT (3 estimated to have occurred on day 11) and Flank (2 on the day after spaying and 1 on each of days 5, 11 and 22). In study 2, the mortality was 0.5%, all within 4 days of spaying. Conclusions In yearling heifers, WDOT spaying resulted in lower morbidity and short-term mortality compared with flank spaying. Both methods compromised the health and welfare of some animals for up to 4 days and body weight gains were reduced during the 6 weeks post spaying.  相似文献   

8.
Our objectives were to determine whether or not ovarian follicles contribute to spontaneous luteal regression in heifers and, if so, when during diestrus do follicles exert their effect. Thirty-one Holstein heifers having displayed at least one estrous cycle (19 to 21 d) were assigned, as available, to randomized blocks for a factorial experiment. Reproductive organs were exposed through a midventral incision on d 9, 12 or 15 postestrus (estrus = d 0). Visible follicles were electrocauterized and both ovaries were x-irradiated (1,500 rads) in treated heifers, whereas ovaries of controls were exteriorized but follicles were not destroyed and ovaries were not x-irradiated. In two additional heifers, the ovary containing the corpus luteum was exteriorized and x-irradiated on d 15 postestrus, but follicles were not electrocauterized. Jugular blood was collected before and every 8 h after surgery until d 24 postestrus. All heifers were ovariectomized on d 24 postestrus to inventory follicles and to weigh corpora lutea. No follicles (greater than or equal to 1 mm diameter) were observed in ovaries from treated animals and concentrations of estradiol-17 beta did not change over time, whereas different numbers of follicles were observed in ovaries from controls and concentrations of estradiol-17 beta increased (P less than .05) during proestrus. Hence, treatment destroyed follicles and prevented follicular development. On d 24 postestrus, corpora lutea from treated heifers (5.5 +/- .5 g) were heavier (P less than .001) than corpora lutea from controls (1.1 +/- .1 g), independent of day when follicles were destroyed.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

9.
Ovarian morphology and follicular systems in yaks of different ages   总被引：5，自引：0，他引：5  
Forty-five female yaks of different ages with known reproductive histories were used to determine the morphology and follicular systems of their ovaries. The histological structure of the ovaries in each age group was found to be similar and resembled that of cattle and buffalo. The atresia of primordial follicles took one form (oocyte atresia); that of growing follicles could be divided into two stages (early and late); and that of Graafian follicular were classified as early, definite and late stage. The details of the several types of atresia are described herein. The average total numbers of primordial follicles per ovary pair in 1-month-old calves, 1-year-old heifers, 2-year-old heifers and 7-10-year-old cows were 53,500 +/- 6300, 32,870 +/- 4500, 22,850 +/- 2800 and 9500 +/- 1200, respectively; those of growing follicles were 210 +/- 76, 815 +/- 95, 895 +/- 142 and 445 +/- 88, respectively; and those of Graafian follicles were 36.5 +/- 14.2, 41.7 +/- 12.3, 37.8 +/- 9.8 and 42.5 +/- 14.5, respectively. The percentage of atretic primordial follicles per ovary pair in 1-month-old calves, 1-year-old heifers, 2-year-old heifers and 7 to 10 year-old cows were 51.6, 55.5, 56.7 and 47.4%, respectively. The average total numbers of atretic growing follicles per ovary pair were 119.5 +/- 21.5, 605.5 +/- 74.3, 721.6 +/- 78.5 and 275.8 +/- 66.3, respectively; those of atretic Graafian follicles were 22.1 +/- 5.6, 21.2 +/- 7.6, 21.5 +/- 4.7 and 25.3 +/- 6.7, respectively.  相似文献   

10.
Forty-six crossbred Hereford heifers were allotted into five experimental groups. Fenprotalene, a prostaglandin analogue, was administered to induce abortion and (or) to regress the corpus luteum (CL) in four groups of heifers about 75 d after conception. The four groups were 1) pregnant heifers, 2) pregnant heifers with the ovary contralateral to the gravid uterine horn removed 24 h after fenprostalene injection, 3) same as Group 2 but with the ipsilateral, rather than the contralateral, ovary removed and 4) heifers with uterus removed (ovaries intact) about 35 d after conception. A fifth group of nonpregnant heifers received implants containing norgestomet from 10 to 76 d after estrus and were given fenprostalene 24 h before removal of the implant. Average length of the first estrous cycle after the fenprostalene injection was 11.2, 8.3, 9.7 and 19.1 for Groups 1, 2, 3 and 5, respectively. Estrous cycles were longer (P less than .05) in norgestomet-treated heifers. Hysterectomized heifers (Group 4) did not exhibit a second estrus by 50 d after fenprostalene treatment; otherwise, all first estrous cycles after the fenprostalene injection were either "short" (7 to 13 d) or "normal" (17 to 23 d). Twenty-two of 24 heifers that aborted had short estrous cycles and two had normal estrous cycles. Short estrous cycles occurred after abortion regardless of whether the ovary ipsilateral or contralateral to the previously gravid uterine horn ovulated. Early regression of the CL (short luteal phase) did not occur in nonpregnant heifers after long-term progestogen stimulation or after hysterectomy, but it did occur in heifers with a previously gravid uterus.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

11.
A new device (Chapingo device) to deposit semen at the base of the uterine horns of cattle was developed at Universidad Autonoma Chapingo, Mexico. Nine Holstein heifers were inseminated by transvaginal laparoscopy, using a laparoscope for cattle and the Chapingo device. A dose of sexed semen (2.1 × 106 spermatozoa) was deposited at the base of the uterine horn ipsilateral to the ovary where the preovulatory follicle was identified. Insemination was achieved in all the heifers, taking on average 13.7 ± 3.1 min per animal. In all cases, it was possible to see both ovaries, the base of the uterine horns and the oviducts. After the procedure, none of the heifers showed any type of complications such as haemorrhage, adhesions or trauma. On days 21 and 22 after insemination, four of the nine heifers (44.4%) returned into oestrus; on day 30 after insemination, one heifer was found to be pregnant by ultrasound. The results show the feasibility of generating pregnancies by transvaginal laparoscopy in heifers inseminated with sexed semen.  相似文献   

12.
In most avian species, only the left ovary and oviduct are developed in the adult bird. Right ovaries and oviducts usually do not mature further after hatching and remain only rudimentary. However, occurrence of a functional right ovary is frequently found in several species of birds of prey. In this study, we investigated the occurrence of the right ovaries and their morphology in these bird species. Four examined wild bird species possessed a right ovary: long‐eared owl, common buzzard, sparrow hawk and goshawk. We used histological and immunohistochemical techniques to evaluate structural differences of the gonads and tried to correlate the findings with folliculogenesis and endocrine functions. The right ovaries showed different sizes and shapes. Cytoskeletal elements (tubulin and vimentin) and α‐smooth muscle actin have been detected in different structures of the right ovaries, but their staining intensity was weaker compared with the left ovary. This shows that also the right ovary is mechanically able to ovulate. We could also demonstrate the expression of oestrogen receptor α and progesterone receptor in the right ovaries, which indicates that also the right ovary can respond to steroid hormone stimuli. We assume that the expression of steroid hormone receptors in the presumptive gonad is still sufficient to mediate the development of a right ovary in the studied species. We conclude that the expression of steroid hormone receptors in the right ovary is involved in its post‐natal development. The histological and immunohistochemical data also imply that in the right ovary, folliculogenesis and ovulation can occur.  相似文献   

13.
作者探讨短期限饲对初情期前母猪和初产母猪繁殖机能的影响及其机理。当体重和脂肪与肌肉比例无变化,短期限饲影响初情期前母猪卵巢繁殖功能。葡萄糖和胰岛素在初情期前母猪繁殖机能中有重要作用。胰岛素是营养与繁殖之间的一个媒介。无内源性激素影响时,短期限饲调节卵巢繁殖功能。在限饲期间,促性腺激素在白天出现明显节奏性释放。短期限饲通过胰岛素影响初产母猪卵泡发育、断奶后发情间隔和排卵率。胰岛素是营养与胚胎存活率之间的介质。短期限饲由于限饲时间不同对初产母猪胚胎存活率影响也不同。分析营养与繁殖机能关系,调节营养使母猪发挥最大繁殖潜力,促进养猪业发展。  相似文献   

14.
Effects of photoperiod on growth, carcass composition and serum concentrations of prolactin, growth hormone and cortisol were determined in prepubertal and postpubertal Holstein heifers. Forty-two prepubertal (avg body wt 84 +/- 3.0 kg) and 42 postpubertal (avg body wt 303 +/- 7.1 kg) Holstein heifers were utilized. Ten prepubertal and 10 postpubertal heifers were slaughtered before treatment began to obtain initial carcass data. The remaining 32 prepubertal and 32 postpubertal heifers were paired by body weight and randomly assigned to short-day (8 h of light: 16 h of dark) or long-day (16 h of light: 8 h of dark) photoperiods. After exposure to treatments for an average of 139 d, 10 prepubertal and 10 postpubertal heifers from each photoperiod treatment were slaughtered. In prepubertal heifers, photoperiod did not affect (P greater than .10) average daily body weight gain, carcass weight, carcass composition, accretion of carcass fat and carcass protein, or serum concentrations of prolactin, growth hormone or cortisol. However, prepubertal heifers exposed to long-day photoperiods had reduced (P less than .01) urinary N tau-methylhistidine excretion compared with heifers given short-day photoperiods. Postpubertal heifers exposed to short-day photoperiods had greater average body weight daily gain than animals exposed to long-day photoperiods. Although there was no effect of photoperiod (P greater than .10) on carcass or fat depot weights, postpubertal heifers exposed to short days had greater (P = .06) percentages of fat and reduced (P = .07) percentages of protein in the soft tissue of the 9-10-11 rib sections. Fat accretion was greater (P less than .05) in carcasses of postpubertal heifers exposed to short days than heifers given long-day photoperiods, but there was no effect (P greater than .10) of photoperiod on protein accretion. Photoperiod did not affect serum concentrations of growth hormone and cortisol, but serum prolactin tended (P less than .10) to be greater in postpubertal heifers exposed to long days. Under the conditions of this experiment, we conclude that exposure to short-day photoperiods stimulated body weight gain and fat accretion in postpubertal but not prepubertal Holstein heifers.  相似文献   

15.
The working hypothesis that a low plane of nutrition during the prepubertal period delays puberty in heifers by retarding the prepubertal increase in secretion of luteinizing hormone (LH) was investigated. Secretion of LH and the responsiveness of the pituitary to LH-releasing hormone (LHRH) were compared in heifers fed a growing diet (which allowed spontaneous occurrence of puberty; n = 12; control) or an energy deficient diet (which delayed puberty; n = 11; delayed) during the prepubertal period. The dietary treatments were initiated when the heifers were 299 +/- 14 (mean +/- SD) d of age (d 0 of the experiment) and continued until d 175 of the experiment (474 +/- 14 d of age). Weight gains were .79 +/- .05 (mean +/- SE) and .21 +/- .03 kg X head-1 X d-1 for control and delayed heifers, respectively. Puberty occurred on d 120 +/- 14 of the experiment (428 +/- 13 d of age) in control heifers, whereas none of the delayed heifers attained puberty during the feeding period. Serum concentration of LH and the frequency of LH pulses increased rapidly during the 175-d feeding period in control heifers. In delayed heifers, serum LH concentration increased less rapidly and no increase in pulse frequency was detected during the experimental period. Amplitude of LH pulses tended to be higher in control than delayed heifers. Responsiveness of LH secretion to LHRH was lower in delayed than control heifers. It is speculated that failure of secretion of LH to increase is the causative factor for delayed puberty when dietary energy is limited during the prepubertal period in heifers.  相似文献   

16.
The objective of the experiment was to compare follicular dynamics, ovulatory response to GnRH, and synchrony of estrus and ovulation among estrous-cycling and prepubertal beef heifers synchronized with a controlled internal drug-release (CIDR)- based or GnRH-PGF(2alpha) (PG) protocol. Estrous-cycling beef heifers were randomly assigned to 1 of 4 treatments (C1, C2, C3, C4), and prepubertal beef heifers were randomly assigned to 1 of 2 treatments (P1, P2) by age and BW. Blood samples were taken 10 and 1 d before treatment to confirm estrous cyclicity status (progesterone > or =0.5 ng/mL estrous cycling). The CIDR Select (C1, n = 12; P1, n = 14)-treated heifers received a CIDR insert (1.38 g of progesterone) from d 0 to 14, GnRH (100 microg, i.m.) on d 23, and PG (25 mg, i.m.) on d 30. Select Synch + CIDR (C2, n = 12; P2, n = 11)-treated heifers received a CIDR insert and GnRH on d 23 and PG at CIDR removal on d 30. The CIDR-PG (C3, n = 12)-treated heifers received a CIDR insert on d 23 and PG at CIDR removal on d 30. Select Synch (C4, n = 12)-treated heifers received GnRH on d 23 and PG on d 30. HeatWatch transmitters were fitted at CIDR removal (C1, C2, C3, P1, and P2) or at GnRH administration (C4) for estrus detection. Ultrasound was used to determine the response to GnRH and the timing of ovulation after estrus. Among the estrous-cycling heifers, ovulatory response to GnRH and estrous response did not differ (P > 0.05). Among the prepubertal heifers, more (P = 0.02) P1 heifers responded to GnRH than P2 heifers, but estrous response did not differ (P > 0.05). Among the estrous-cycling heifers, variance for interval to estrus after PG was reduced (P < 0.05) for C1 compared with each of the other treatments, and C3 [corrected] was reduced (P < 0.05) compared with C2 [corrected] Variance for interval to ovulation after PG was reduced (P < 0.05) for C1 compared with each of the other treatments. Among the prepubertal heifers, there was no difference (P > 0.05) in variance for interval to estrus or ovulation. Results from C1 and P1 (T1) and C2 and P2 (T2) were combined to compare T1 and T2 among mixed groups of estrous-cycling and prepubertal heifers. Response to GnRH was greater (P < 0.01; 81% T1 and 39% T2), and variances for interval to estrus and ovulation for T1 were reduced (P < 0.01) compared with T2. In summary, CIDR Select improved (P < 0.01) the synchrony of estrus and ovulation compared with Select Synch + CIDR.  相似文献   

17.
In this study, we examined the locational effect (left or right ovary) of the preovulatory follicle (PF) on fertility in dairy heifers. In total, 1,111 artificial inseminations (AI) were analyzed. At AI, PF locations were examined using rectal palpation, and heifers were divided into two groups on their PF locations: (i) the PF located in the left ovary (L‐PF); and (ii) the PF located in the right ovary (R‐PF). Pregnancy was diagnosed by rectal palpation 60 days after AI. The conception rate was 50.7% in all heifers. Conception rate was significantly higher in the L‐PF (60.1%) than in the R‐PF (46.2%). The conception rate was significantly lower by sexed semen (48.6%) than conventional semen (59.1%). Conception rates divided by the semen type (sexed: n = 896, conventional: n = 215) were significantly higher in the L‐PF than in the R‐PF for both semen types (sexed; L‐PF vs. R‐PF: 57.3% vs. 44.4%, conventional; L‐PF vs. R‐PF: 72.3% vs. 53.3%). In addition, season, age, AI number, and the number of re‐inseminations at the same estrus did not affect conception rates. In summary, PF development in the left ovary was associated with increased conception rates in dairy heifers.  相似文献   

18.
Mycoplasma bovigenitalium (M. bovigenitalium, strain AL) was inoculated by insemination during estrous into the uterus or the cervix of 12 heifers. The inoculum consisted of a mixture of M. bovigenitalium (strain AL) and diluted semen taken from a highly fertile bull free of mycoplasma infection. Mycoplasma organisms were recovered 3 days postinoculation (PI) from the vaginal mucous of eight of 12 inoculated heifers, and at weekly intervals thereafter until the time of necropsy. All inoculated heifers had granular vulvovaginitis; some also had mucopurulent vaginal discharges. Six of the 12 infected heifers were inseminated more than once, yet none became pregnant. Macroscopic changes observed at necropsy in the genital tracts, in addition to granular vulvovaginitis, consisted of mucopurulent discharges emananting from the uterus, cervix, and vagina. All ovaries had corpora lutea. Mycoplasmas were recovered at necropsy from eight of the 12 heifers. Isolations were made from the vaginal wall, cervix, uterus, right and left oviducts, and the ovaries. All recovered mycoplasms were identified as M. bovigenitalium. It was concluded that M. bovigenitalium (strain AL) can cause inflammatory changes and infertility in heifers.  相似文献   

19.
A determination of age of the prepubertal gilt at which ovaries affect uterine growth is necessary before establishing the extent to which length of uterus is influenced by inherent differences, as opposed to those due to ovarian secretions. In Exp. 1 and 2, the effect of presence of ovaries on uterine growth was determined following ovariectomy in 186 crossbred gilts. The uterus was examined 40 or 80 d after ovariectomy for length, weight and diameter. Growth of uterine horns in gilts from 20 to 60 d of age was equal with or without ovaries. Uterine horns in ovariectomized gilts continued to grow slowly from 60 to 140 d of age and then remained static to 180 d of age. Uterine horns in gilts with ovaries increased rapidly in length, weight and diameter, with concomitant increase in ovarian weight between 100 and 180 d of age. In Exp. 3, uterine growth and ovarian compensation after unilateral ovariectomy and hysterectomy at 60 d of age were determined in 85 crossbred gilts from 60 to 180 d of age to evaluate the unilateral ovariohysterectomy model for studying association of uterine length before puberty and subsequent uterine capacity. In response to removal of an ovary and a uterine horn, the remaining ovary compensated, but the remaining uterine horn did not. This study demonstrated that the ovaries did not influence uterine growth until after 60 d of age and that unilateral ovariohysterectomy could be performed as early as 60 d of age without altering consequent normal uterine growth.  相似文献   

20.
The aim of the present study was to assess the effects of the ovum pick-up (OPU) technique on animal well-being. Eight dairy heifers were subjected to 4 months of twice-weekly OPU. The physiological response to OPU was recorded in four heifers at two sessions, at the beginning (time 1) and at the end (time 2) of the 4-month period. Heart rates were measured and blood was analysed for cortisol, vasopressin and PG-metabolite before, during (every 5 and 2(1/2) min), and after the OPU sessions. Reactions to each subprocedure of OPU ('restraint', 'epidural', 'device in' and 'puncture') were closely observed. In all heifers, reactions to the OPU procedures were also noted throughout the experimental period, and changes in routine behaviour, oestrous behaviour, body temperature, or other clinical traits were recorded. Subsequent to the experiment, the ovaries and tails were carefully inspected. At time 1, there was an insignificant increase in heart rate and cortisol throughout the OPU procedure. At time 2, these two parameters increased significantly, but both parameters declined to pre-OPU levels 10 min after completion of the procedure. No significant changes were seen in vasopressin or PG-metabolite at time 1 and time 2. Behaviourally, the heifers showed the strongest response to epidural anaesthesia, with a tendency for more intense response during the late 4-month sessions. The response to 'device in' and 'puncture' varied among individuals independently of time. There were no changes in the routine or oestrous behaviour throughout the experiment and no signs of clinical disorders. No major pathological changes were macroscopically seen in the ovaries and tails subsequent to the 4 months of OPU. In conclusion, the heifers showed a response to OPU, mostly to administration of epidural anaesthesia. However, we demonstrated that epidural anaesthesia can be administered in a way causing less discomfort.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号