Aström G
Acta Vet Scand. 1970;11(3):415-26. doi: 10.1186/BF03547968.
Sixty-five heifers in different stages of the oestrus cycle were fed norethisterone once daily for 17 days at doses of 0.2, 0.6 and 1.0 mg/kg body weight. During treatment swollen vulva, mucus discharge, open and reddened portio and udder enlargement were noted. Norethisterone was effective in suppressing oestrus and ovulation at doses of 0.6 and 1.0 mg/kg. Extremely good heat-synchronization followed the treatment and 98 % of the heifers came on heat within a two-day period. Fifty-five % conceived after the first insemination. In the group receiving 0.2 mg norethisterone per kg, three out of 13 heifers showed psychic heat during treatment. Poor heat synchronization and low conception rate were obtained in this group. A possible effect of cycle stage on heat synchronization was noted only in the 0.2 mg group where a better result was obtained when treatment began in the follicular phase.
65头处于发情周期不同阶段的小母牛，每天按0.2、0.6和1.0毫克/千克体重的剂量服用炔诺酮，持续17天。治疗期间，观察到外阴肿胀、黏液分泌、子宫颈开张且发红以及乳房肿大。炔诺酮在0.6和1.0毫克/千克的剂量下能有效抑制发情和排卵。治疗后热同步效果极佳，98%的小母牛在两天内发情。首次输精后55%受孕。在每千克服用0.2毫克炔诺酮的组中，13头小母牛中有3头在治疗期间出现精神性发情。该组热同步效果差且受孕率低。仅在0.2毫克组中注意到周期阶段对热同步可能有影响，在卵泡期开始治疗时效果更好。
