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Study on the influences of hexestrol dicaprylate on fattening male pigs ond bull calves
Hex. D の雄子豚と雄子牛lこ対する去勢様効果，発育促進および肉質の改善効果を試験する目的で本研究を行なった.結果を要約すれば次の通りである.
1 生後39日令の雄子豚に20mg/kgのHex.D を注射した場合，と殺時の精巣組織はほぼ正常な精子形成がみられたが，対照の去勢豚に比べ発育と肉質に差異はなかった.
2 生後56日令と136日令にそれぞれ15mg/kgのHex.D を注射した雄子豚は， 135日令まで精子形成がみられなかった.その後この機能はやや恢復する傾向を示したが，精巣の大きさの変化，性生態および肉質から判断してHex.Dの去勢様効果が認められた.
3 生後3-4カ月令の雄子牛にHex. Dを20mg/kg，さらにその9ヵ月後に2mg/kgを注射した場合，去勢牛と比較して発育の効果は明らかでなかったが，精巣の組織像と肉質および生態などからみて去勢様効果が認められた.
This research has been carried out in order to examine the emasculative effect of Hexestrol dicaprylate (Hex. D) on fattening male pig and bull calves, and also in order to determine the consequences of Hex. D on the growth and on the improvement of quality of meat or poak.
In the first experiment, 20mg/kg of Hex. D were injected into 2 pure bred Yorkshire male pigs 39 days old, compared with 3 barrows of littermate.
In the second experiment, 15mg/kg of Hex. D were injected into another Yorkshire male pig on of the 56th day and 136th day after birth, respectively.
As for the experiment on bull calf fattening, 3 young bull calves (Japanese breed) were used. One of them was castrated 130 days after birth, while the other two were twice treated with intro-masculor injections of Hex. D the first time 20mg/kg at the time of 103-123 days and the second time 2mg/kg at the time of 372-393 days.
The results can be summarized as following;
1. Effects on the male pigs.
There was no difference between the growth of the male pigs and that of the barrows in the first experiment. Moreover, the growth of the testes of the male pigs were found as normal. Judging from the histological observations, no emasculative effect could be discovered in the male pigs. In the second experiment, there were also no observable influences of Hex. D on the increase in body weight, on the fattening and on their feed conversion.
However, in the second experiment, as shown by observation on his testis tissues, obtained by biopsy, his spermatogenesis was kept suppressed, up to 135 days after birth. In the latter stage of raising, his spermatogenesis was seen tending to recovery in the case of male pig, on the bases of observations
on the growth and weight of his testis and the sexual behaviour. The effect of Hex. D on the meat quality was also recognized in the male pigs regardless the injection procedures employed. The quality of their pork was similar to that of the barrow.
2. Effects of the fattening in bull calves.
The growth of the calves testis was considerably suppressed by injection of Hex. D. This was discerned not only from their changings in size but also from the histological references of the testes.
There were no significant differences between the growth and the feed convertion of the bull calves injected with Hex. D, and those of the steer.
The meat grade and the fat status of the Hex. D-injected bull calves were somewhat superior to those of the steer; the effects of Hex.-D on the fattening of bull calf were noticed as well as the suppression of the function of their spermatgenesis.
From the result of this study could be recognize emasculative effect that meat of the Hex. D-injected male pigs and bull calves can fatten as the same grade of barrow and steer, depending on the repression of androgen.