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排序方式： 共有102条查询结果，搜索用时 15 毫秒
71.
L Mateus L Lopes da Costa JJ Alfaro Cardos & J Robalo Silva 《Reproduction in domestic animals》2002,37(1):57-60
The efficiency of treatments for unobserved oestrus and their effect on the reproductive performance of a dairy cattle herd with low oestrous detection rate till 60 days post‐partum (dpp), attributed to the declivous and slippery concrete floor were investigated. The herdsman requested advice in order to improve the mean days open of the herd, but no investments were allowed because a new unit was about to be built. Due to the low oestrus detection rate of the herd, the breeding policy was to inseminate at the first detected post‐partum oestrus. Cows were examined at 20–30 dpp to assess uterine involution, ovarian activity and prevalence of reproductive disorders and, at 60 dpp if no previous oestrus was detected. Each examination included palpation per rectum, ultrasound scanning and collection of a blood sample for plasma progesterone (P4) measurement. Cows with unobserved oestrus till 60 dpp were allocated either to a treatment group (n=139) or to a control group (n=139). Three treatments were used: (a) injection of PGF2α (PG) upon detection of a corpus luteum (CL; n = 30), cows not observed in oestrus being re‐injected 11–12 days later. AI was at oestrus; (b) PRID (n=35) or Crestar (n=74) devices kept in situ for 12 and 9 days, respectively, were associated to an injection of PG and of equine chorionic gonadotrophin (eCG) at device removal. Cows were double‐fixed time‐inseminated at 48 and 72 h after device removal. All treated cows were examined at 48–72 h after treatment to confirm oestrus. The percentage of cows detected in oestrus up to 60 dpp remained unchanged through the trial (35 and 47% for years before intervention: 1994–95; 51 and 48% for years of intervention: 1996–97). In contrast, the oestrous detection rate was high both in treated (93%) and control (100%) cows. This possibly resulted from an improvement in the oestrous detection efficiency of the herd's personnel and from examination of cows at 48–72 h after treatment. Treated and control cows had identical conception rate (CR; 36 and 37%, respectively) and reproductive performance. However, the mean days open of the herd in 1996 was significantly improved in comparison with previous years (mean ± SEM: 134 ± 6, 126 ± 5, 110 ± 4 and 114 ± 5 days, for years 1994, 1995, 1996 and 1997, respectively, p < 0.05, ANOVA ). Conception rate to AI up to 40 dpp was significantly reduced, compared with the period between 60 and 100 dpp but, mean days open were significantly improved in cows inseminated up to 60 dpp, compared with thereafter (p < 0.05). 相似文献
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MC Esteso MR Fernández-Santos AJ Soler V Montoro F Martínez-Pastor JJ Garde 《Reproduction in domestic animals》2009,44(2):206-211
Computer-assisted sperm morphometry analysis (CASMA) was used in this study to identify sperm morphometric subpopulations in Iberian red deer epididymal sperm samples. Epididymal sperm samples were collected from 37 mature stags and were divided. One portion was diluted in a Tris–citrate–egg yolk medium. A microscope slide was prepared from single extended sperm samples prior to freezing. The remainder of each sample was frozen in nitrogen vapours using a conventional protocol. After thawing, sperm smears were prepared as described for extended samples. All slides were air-dried and stained with Hemacolor® . The sperm-head dimensions for a minimum of 145 sperm-heads were analyzed from each sample by means of the Sperm-Class Analyser® , and the mean measurements recorded. Each sperm-head was measured for four primary sperm-head parameters, and five parameters of head shape. All sperm morphometric parameters evaluated were placed in a statistical database and a multivariate cluster analysis was performed. The clustering analyses, based on 10 867 individual spermatozoa, revealed the existence of three subpopulations (SP1 , SP2 , SP3 ) of spermatozoa with different morphometric characteristics (p < 0.001). The proportion of spermatozoa present in any of the three subpopulations remained constant (p > 0.05) through the cryopreservation process. Pre-freeze and post-thaw sperm quality was in vitro evaluated by microscopic assessments of individual sperm motility and of plasma membrane and acrosome integrities. In conclusion, our results show that applying the CASMA techniques and multivariate cluster analyses, it was possible to determine that three subtle subpopulations of spermatozoa with different morphometric characteristics coexist in red deer semen. 相似文献
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H Ülker A Y&#;lmaz F Karaku&#; M Yörük C Buda&#; DM deAvila JJ Reeves 《Reproduction in domestic animals》2009,44(4):593-599
This study was designed to evaluate the effectiveness of a luteinizing hormone releasing hormone (LHRH) fusion protein immunization on reproductive traits in ram lambs including the changes in histology and ultrasonographic appearance of testis. Thirty native ram lambs at 19 weeks of age were divided into control (C, n = 10), immunization (I, n = 10) and castration (E, n = 10) groups. Animals in immunization group were immunized against LHRH using ovalbumin‐LHRH‐7 (OL) protein generated by recombinant DNA technology as a primary and a booster injection at 19 and 23 weeks of age respectively. Animals were bled via jugular venepuncture at 2‐week intervals to determine LHRH antibody and testosterone concentrations. Bi‐weekly ultrasonographic examination of the testes was performed to determine the changes in ultrasonographic appearance as the age increased. Biopsied testicular tissues taken at 19, 29 and 41 weeks age were also evaluated. At 41 weeks of age, animals were slaughtered. Semen and epididymis were evaluated for the presence of sperm cells. Testicular development and sperm production were suppressed in the immunized animals. Semineferous tubule diameters decreased, basal membrane of the tubule was thickened and hyalinized in immunized ram lambs. While testes of control animals gained their normal ultrasonographic appearance as the age increased, immunized animals had uniform hypoechogenic testicular structure as observed at 19 weeks of age until slaughter. Simultaneous histological and ultrasonographic evaluations indicated that the changes in testicular histology could partly be monitored via ultrasonographic imaging. Nevertheless, it is difficult to claim that ultrasonographic image reflects the exact changes in such instances. In conclusion, these results indicate that recombinant OL fusion protein is effective in immunocastration in ram lambs and has a potential to be used as an alternative to physical castration. Further research studies should be conducted to help assess reproductive status of testes from ultrasound images. 相似文献
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