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161.
In order to evaluate an artificial insemination programme and reproductive efficiency of dairy herds in Uruguay, a survey was conducted with five dairy farms, utilizing a total of 768 lactating Holstein cows. Precision of oestrous detection was assessed by one milk progesterone sample taken on day of breeding and was 11.1%. Two additional samples taken at day 10 and 23 were used to confirm ovulation and early pregnancy. Accuracy of pregnancy estimation by milk progesterone was 70.4%. Reproductive efficiency was determined by the analysis of records. Average intervals from calving to first service were 101 days and to conception 132 days and these were affected by parity, body weight and body condition at calving, but not at breeding, or by milk production. Oestrous detection rates and pregnancy rates were 37.5 and 15.6%, respectively. It was concluded that losses in reproductive efficiency in dairy farms of Uruguay in a seasonal artificial insemination programme were mainly due to unobserved heats, rather than incorrect oestrous detection. 相似文献
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Antibodies to cell membrane antigens associated with human T-cell leukemia virus in patients with AIDS 总被引:24,自引:0,他引:24
M Essex M F McLane T H Lee L Falk C W Howe J I Mullins C Cabradilla D P Francis 《Science (New York, N.Y.)》1983,220(4599):859-862
The acquired immune deficiency syndrome (AIDS), which has recently occurred at increasing rates in homosexual men, intravenous drug users, and others, is characterized by the development of Kaposi's sarcoma and several opportunistic infections including pneumonia caused by Pneumocystis carinii. Serum samples from patients with AIDS and from matched and unmatched control subjects were examined for the presence of antibodies to cell membrane antigens associated with human T-cell leukemia virus. Nineteen of 75 of the AIDS patients had antibodies directed to surface antigens of Hut 102, a reference T lymphoid cell line infected with leukemia virus, as did two of the 336 control subjects. 相似文献
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Oral squamous cell carcinomas (OSCCs) are common and often fatal feline neoplasms. Factors that predispose to neoplasm development in cats are poorly defined. Around 25% of human OSCCs are caused by papillomaviruses (PVs). To determine if PVs are associated with OSCCs in cats, three sets of consensus primers were used to evaluate 20 feline OSCCs and 20 non-neoplastic feline oral lesions for the presence of PV DNA. Papillomaviral sequences were detected within one OSCC, but no non-neoplastic lesion. Sequencing of the amplified DNA revealed a previously unreported PV that was most similar to human PV type 76. This is the first time PV DNA has been amplified from the oral cavity of a cat. However, while these results suggest that feline gingival epithelial cells can be infected by PVs, they do not support a causal association between viral infection and the development of feline OSCCs. 相似文献
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Abstract Fifteen annual cool season legumes were compared under dryland conditions on two sites in the Dohne Sourveld. These sites were Dohne, with a mild but dry winter and an average rainfall of 743 mm per year, and Grasslands, a colder, wetter site. Vicia spp were among the highest‐yielding cultivars at both sites. At Dohne the mean yield of the legumes that performed best was slightly more than that of the veld and their use does not seem worthwhile. At Grasslands, the mean yield of the highest‐yielding legumes was above 6 t/ha/year and their use does seem economical. The high yield of the legumes during wet seasons suggests that their cultivation under irrigation should be profitable. Under these or high rainfall conditions seed production may be lucrative. 相似文献