Departamento de Fisiología, Facultad de Veterinaria, Universidad de la República, Montevideo, Uruguay.
Theriogenology. 2012 Nov;78(8):1796-9. doi: 10.1016/j.theriogenology.2012.07.001. Epub 2012 Aug 25.
Vaginal secretions are an important source of chemical signals, which affect ewes' attractiveness. Moreover, alterations of vaginal flora reduce sexual attractiveness of estrous ewes. As intravaginal sponges containing progestagens (widely used for estrous synchronization) affect vaginal flora, our aims were to determine if estrous ewes pretreated with intravaginal sponges were less attractive than ewes displaying spontaneous estrus, and if the addition of antibiotic to the sponge mitigated the decreased sexual attractiveness. Seventy-two estrous ewes were used in experiment 1: in 36, estrus was synchronized with commercial intravaginal sponges (50 mg medroxyprogesterone acetate for 14 days, group MAP1), whereas the other 36 were given a PGF2α analogue 19 to 20 days earlier and displayed spontaneous estrus (group C1). In experiment 2, 72 ewes were treated with intravaginal sponges for 14 days; for 36 ewes, the sponges contained 0.02 mg oxytetracycline (group Ox), whereas there was no antibiotic in the sponges for the remaining 36 ewes (group MAP2). In both experiments, sexual attractiveness was determined in 12 groups of six estrous ewes (three MAP1 vs. three C1, and three MAP2 vs. three Ox for Experiments 1 and 2, respectively) located in a 4 × 4 m pen. Courting and mating time that each ram spent with each ewe was recorded. After 5 min, the ewe with which the ram spent more time (most attractive ewe, ranked one, scale one to six) was taken out from the pen. The procedure was repeated until the ram ranked all six ewes, and repeated in the 12 groups in both experiments. In experiment 1, C1 ewes were more attractive than MAP1 ewes (ranks: 2.9 ± 0.3 vs. 4.1 ± 0.3, mean ± SEM, respectively; P < 0.002). In experiment 2, sexual attractiveness of MAP2 and Ox ewes was similar (3.5 ± 0.3 vs. 3.4 ± 0.3, respectively). We concluded that the use of intravaginal sponges impregnated with medroxyprogesterone acetate negatively affected ewes' sexual attractiveness, but this decrease was not mitigated by inclusion of a local antibiotic.
阴道分泌物是化学信号的重要来源，这些信号会影响母羊的吸引力。此外，阴道菌群的改变会降低发情母羊的性吸引力。由于含有孕激素的阴道内海绵（广泛用于发情同步）会影响阴道菌群，我们的目的是确定用阴道内海绵预处理的发情母羊是否比表现自发发情的母羊吸引力更小，以及向海绵中添加抗生素是否可以减轻性吸引力的降低。在实验 1 中，我们使用了 72 只发情母羊：在 36 只母羊中，使用商业阴道内海绵（50mg 醋酸甲羟孕酮，持续 14 天，MAP1 组）同步发情，而另外 36 只母羊在 19 到 20 天前用前列腺素 F2α类似物处理，并表现自发发情（C1 组）。在实验 2 中，72 只母羊用阴道内海绵处理 14 天；对于 36 只母羊，海绵中含有 0.02mg 土霉素（Ox 组），而另外 36 只母羊的海绵中没有抗生素（MAP2 组）。在这两个实验中，将 12 组 6 只发情母羊（每组 3 只 MAP1 与 3 只 C1，每组 3 只 MAP2 与 3 只 Ox，分别用于实验 1 和实验 2）放置在一个 4x4m 的围栏中。记录每只公羊与每只母羊交配和求爱的时间。5 分钟后，公羊与花时间最多的母羊（最有吸引力的母羊，排名第一，范围为 1 到 6）进行交配。该过程重复进行，直到公羊对所有 6 只母羊进行了排序，并在两个实验的 12 个组中重复进行。在实验 1 中，C1 母羊比 MAP1 母羊更有吸引力（排名：2.9±0.3 与 4.1±0.3，平均值±SEM，分别；P<0.002）。在实验 2 中，MAP2 和 Ox 母羊的性吸引力相似（3.5±0.3 与 3.4±0.3，分别）。我们得出结论，使用含有醋酸甲羟孕酮的阴道内海绵会降低母羊的性吸引力，但通过加入局部抗生素并不能减轻这种下降。
