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101.
Extract

Lytic lesions with microscopic features similar to those of vaccine-site sarcomas were diagnosed in the distal femur of two young neutered male cats, one a 20-month-old Birman and the other an 18-month-old domestic short-hair (DSH). Radiographically, there was extensive destruction of trabecular and cortical bone in the metaphysis and/or epiphysis of the distal femur. The DSH cat also had angular deformity of the distal femur due to asymmetrical involvement of the physis. Histologically, the lesions in both cats consisted of dense, interwoven bundles of fibrous connective tissue, amongst which there were variable numbers of plump malignant mesenchymal cells, often with very large, hyperchromatic nuclei and irregularly shaped nucleoli. Several focal aggregates of small lymphocytes were present in both tumours. Although neither cat had apparently been vaccinated in the hindlimb it is possible that the tumours had been triggered by injection of some other irritant material.  相似文献   
102.
To ensure sufficient numbers of pregnant females, particularly at hotter times of the year, hormonal induction of gilt oestrus may be necessary. However, the gilt oestrus and ovulation responses to gonadotrophin treatment have often proven unpredictable. The objective of this study was to examine possible reasons for this unpredictability. Prepubertal gilts (approximately 150 days of age, n = 63) were assigned to one of three treatments: injection of 300 IU hCG (n = 15); pre-treatment with 100 mg FSH in polyvinylpyrrolidinone administered as 2 × 50 mg injections 24 h apart, followed by 600 IU eCG at 24 h after the second FSH injection (n = 23); or FSH pre-treatment as above followed by 300 IU hCG at 24 h after the second FSH injection (n = 25). To facilitate oestrus detection, gilts were exposed to a mature boar for 15 min daily for 7 days. Blood samples were obtained on the day of eCG or hCG injection and again 10 days later and gilt ovulation responses determined based on elevated progesterone concentrations. The oestrus responses by 7 days were 6.7%, 17.5% and 64.0% for gilts treated with hCG, FSH + eCG and FSH + hCG, respectively (p < 0.001). The oestrous gilt receiving hCG alone and one oestrous FSH + hCG gilt did not ovulate, all other oestrous gilts ovulated. A further two anoestrous FSH + eCG-treated gilts ovulated. These data suggest that FSH pre-treatment facilitated the development of ovarian follicles to the point where they became responsive to hCG, but had little effect on the response to eCG.  相似文献   
103.
In this study, motility and oxidative–antioxidant capacity (thiobarbituric acid‐reactive substance level [TBARS], superoxide dismutase [SOD], catalase [CAT] and glutathione reductase [GR]) of beluga sturgeon (Huso huso) sperm, stored for 6 days at ?80°C, were evaluated. After 2 days of storage, sperm motility was significantly decreased (no motile sperm were observed after 6 days of storage; < .05), while TBARS and SOD values were significantly increased (< .05). CAT and GR activities did not show significant changes among storage times (> .05). Furthermore, all investigated parameters showed a significant difference between semen stored at 4°C (control) and ?80°C during in vitro storage (< .05). Data from this work can potentially be useful in sturgeon sperm cryobanking.  相似文献   
104.
Assessment of urine levels of luteinizing hormone (LH) for predicting the reproductive status of animals is in practice. The aim of this study was to predict the period of ovulation based on the urine levels of LH for timed‐artificial insemination to increase the conception rate in buffaloes, which are naturally silent‐oestrous animals. Level of LH in urine was assessed using ELISA, and a cut‐off LH concentration for prediction of ovulation period was obtained using receiver operating characteristic analysis. Artificial insemination was performed before‐ and after ‐positive prediction of ovulation period adopting this method, and the rates of conception were assessed. Urine LH level of 105 mIU/ml (n = 14) was derived as a cut‐off concentration which predicts the ovulation period. The buffaloes in the positively predicted group (day 1 or 2) inseminated via intracervical route had an increase in the conception rate (83.33%); however, the insemination in the before‐positive‐prediction group resulted in poor conception rates (day 0; 16.66%) compared to that of the naturally inseminated group (day 0; 75.0%). In conclusion, the urinary LH would possibly be a fairly reliable predictor of the ovulation period. The day when cut‐off LH concentration is obtained may be taken as the most favourable time for artificial insemination, so as to attain a much better rate of conception in the buffalo.  相似文献   
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107.
Frozen-thawed (FT) boar sperm have a reduced fertile life, due in part to a capacitation-like status induced by cooling. Reversal of this cryocapacitation in vitro by exposure to boar seminal plasma (SP) has been demonstrated. The objective of these studies was to determine the effect of SP on the ability of FT sperm to create an oviductal sperm reservoir following artificial insemination (AI). In Experiment one, 35 pre-pubertal gilts were injected (IM) with 400 IU eCG plus 200 IU hCG to induce oestrus. At detection of oestrus, gilts were inseminated with 3 x 10(9) live sperm, either fresh (FS; n = 13), FT (n = 10), or FT supplemented with 10% v/v SP (n = 12). Gilts were killed 8 h later, their reproductive tracts recovered and the uterotubal junctions (UTJs) flushed to recover sperm. Fewer (p < 0.01) sperm were recovered following FT, compared to FS, inseminations, and there was no evident effect of SP. In Experiment two, 30 pre-pubertal gilts received IM injections of 1000 IU eCG followed by 5 mg pLH 80 h later to control time of ovulation. Gilts were inseminated with 3 x 10(9) live FS sperm (n = 6), FT sperm (n = 15) or FT sperm plus 10% SP (n = 9) at 12 h before ovulation and then sacrificed 8 h later. The UTJs were dissected and flushed for sperm recovery. Fewest (p < 0.001) sperm were recovered following FT insemination and there was no evident effect of SP. These data demonstrate that the size of the sperm reservoir is markedly reduced in gilts inseminated with FT sperm. However, the lack of effect of SP suggested that either it did not reverse cryocapacitation or that such a reversal does not impact the in vivo ability to create a sperm reservoir.  相似文献   
108.
There are currently four major options for control of ostertagiasis and other ruminant gastrointestinal parasites. These are the traditional, suppressive, integrated and strategic approaches. Strategic dosing is the most realistic and beneficial approach for most regions of the world, including the U.S.A. It is effective, practical, labor-saving and can yield big economic returns. Today this approach is even more appropriate because of important advances in the technology of controlled release and pulse-release devices. Top priority in worm control programs should be given to dairy replacement heifers in their first year at pasture and to beef calves in the immediate post-weaning period. This is preferable to recommendations for blanket treatment of all beef and dairy cattle, regardless of age, immune status or pasture infectivity. An anthelmintic overkill is both wasteful and potentially harmful in that it increases the selection pressure for drug resistance. It is suggested that better dissemination of information is needed to make producers aware of the benefits of strategic dosing programs. This would eliminate much of the confusion about parasite control and focus attention on simple and effective programs that could significantly reduce current losses to the livestock industries.  相似文献   
109.
Records on 1,180 young Angus bulls and heifers involved in performance tests were used to estimate genetic and phenotypic parameters for feed intake, feed efficiency, and other postweaning traits. The mean age was 268 d at the start of the performance test, which comprised 21-d adjustment and 70-d test periods. Traits studied included 200-d weight, 400-d weight, scrotal circumference, ultrasonic measurements of rib and rump fat depths and longissimus muscle area, ADG, metabolic weight, daily feed intake, feed conversion ratio, and residual feed intake. For all traits except the last five, additional data from the Angus Society ofAustralia pedigree and performance database were included, which increased the number of animals to 27,229. Genetic (co)variances were estimated by REML using animal models. Direct heritability estimates for 200-d weight, 400-d weight, rib fat depth, ADG, feed conversion,and residual feed intake were 0.17 +/- 0.03, 0.27 +/- 0.03, 0.35 +/- 0.04, 0.28 +/- 0.04, 0.29 +/- 0.04, and 0.39 +/- 0.03, respectively. Feed conversion ratio was genetically (r(g) = 0.66 ) and phenotypically (r(p) = 0.53) correlated with residual feed intake. Feed conversion ratio was correlated (r(g) = -0.62, r(p) = -0.74) with ADG, whereas residual feed intake was not (rg = -0.04, r(p) = -0.06). Genetically, both residual feed intake and feed conversion ratio were negatively correlated with direct effects of 200-d weight (r(g) = -0.45 and -0.21) and 400-d weight (r(g) = -0.26 and -0.09). The correlations between the remaining traits and the feed efficiency traits were near zero, except between feed intake and feed conversion ratio (r(g) = 0.31, r(p) = 0.23), feed intake and residual feed intake (r(g) = 0.69, r(p) = 0.72), and rib fat depth and residual feed intake (r(g) = 0.17, r(p) = 0.14). These results indicate that genetic improvement in feed efficiency can be achieved through selection and, in general, correlated responses in growth and the other postweaning traits will be minimal.  相似文献   
110.
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