Faigl Vera, Keresztes Mónika, Márton Alíz, Fébel Hedvig, Kulcsár Margit, Nagy Sándor, Cseh Sándor, Solti László, Huszenicza Gyula
Szent István University Department and Clinic for Obstetrics and Reproduction, Faculty of Veterinary Science István u. 2 H-1078 Budapest Hungary.
Acta Vet Hung. 2011 Dec;59(4):497-510. doi: 10.1556/AVet.2011.036.
Seasonal differences in the resumption of postpartum ovarian activity, milk production and periparturient metabolic status were investigated in lactating non-suckling dairy Awassi sheep in two consecutive experiments. In Experiment 1, autumn-lambing (AL, n = 27) and spring-lambing (SL, n = 37) ewes were investigated. Ovarian activity was monitored by means of individual progesterone (P4) profiles from day 5 to day 100 post partum. Most of the AL dams (89%) ovulated till day 35 after parturition and became cyclic thereafter. Incidence of persistent corpus luteum (CLP) and short luteal phases (sCL) was frequent (18% and 29%, respectively) among non-conceiving dams. In contrast, only 24% of the SL ewes ovulated before day 35. P4 levels during the luteal phase were lower in cyclic animals, and the cycle was longer in SL than in AL animals. No CLP or sCL was detected in the spring-lambing group, and 61% of SL ewes remained acyclic till the end of the trial. Lactation length was significantly longer in SL dams than in AL ewes (P = 0.008). According to the plasma metabolites (BHB, NEFA) and metabolic hormones (insulin, IGF-I, thyroxine) examined, negative energy balance did not appear in any of the animals. However, seasonal differences were seen in IGF-I and thyroxine levels, which were higher in the SL dams. In Experiment 2, influence of additional lighting was studied in autumn-lambing ewes. The long-day photoperiod (LD, n = 23) group was exposed to artificial light from sunset till midnight (approx. 16 h light/8 h dark) from some weeks before the expected date of delivery in mid-September until the end of December. The control group (n = 25) experienced only natural daylength. The first postpartum ovulation tended to occur later in the LD animals than in the controls (P = 0.047). The lactation of the LD group tended to be longer (P = 0.061). NEFA, BHB, insulin, IGF-I and thyroxine levels did not differ between the groups.
(i) The ovarian function of the Awassi population is seasonal under temperate continental climate conditions. (ii) The first postpartum ovulation of non-suckling, autumn-lambing dams may occur very early, even before the completion of uterine involution. (iii) Additional artificial lighting may delay the time of first postpartum ovulation in AL ewes. (iv) Postpartum negative energy balance is unlikely to occur in dairy Awassi ewes even in high-producing intensive systems.
在两项连续的实验中，对泌乳期非哺乳的阿瓦西奶羊产后卵巢活动恢复、产奶量和围产期代谢状态的季节性差异进行了研究。在实验1中，对秋季产羔（AL，n = 27）和春季产羔（SL，n = 37）的母羊进行了研究。从产后第5天到第100天，通过个体孕酮（P4）曲线监测卵巢活动。大多数AL母羊（89%）在产后35天内排卵，此后进入发情周期。在未受孕的母羊中，持续性黄体（CLP）和短黄体期（sCL）的发生率较高（分别为18%和29%）。相比之下，只有24%的SL母羊在35天前排卵。发情周期动物的黄体期P4水平较低，SL动物的发情周期比AL动物长。在春季产羔组中未检测到CLP或sCL，61%的SL母羊在试验结束时仍未发情。SL母羊的泌乳期明显长于AL母羊（P = 0.008）。根据检测的血浆代谢物（BHB、NEFA）和代谢激素（胰岛素、IGF-I、甲状腺素），任何动物均未出现负能量平衡。然而，在IGF-I和甲状腺素水平上存在季节性差异，SL母羊中的这些水平较高。在实验2中，研究了额外光照对秋季产羔母羊的影响。长日照光周期（LD，n = 23）组从9月中旬预期分娩日期前几周直到12月底，从日落到午夜暴露于人造光下（约16小时光照/8小时黑暗）。对照组（n = 25）仅经历自然日照长度。LD组动物的首次产后排卵往往比对照组晚（P = 0.047）。LD组的泌乳期往往更长（P = 0.061）。两组之间的NEFA、BHB、胰岛素、IGF-I和甲状腺素水平没有差异。
（i）在温带大陆性气候条件下，阿瓦西种群的卵巢功能具有季节性。（ii）非哺乳、秋季产羔母羊的首次产后排卵可能非常早，甚至在子宫复旧完成之前。（iii）额外的人工光照可能会延迟AL母羊首次产后排卵的时间。（iv）即使在高产集约化系统中，阿瓦西奶羊产后也不太可能出现负能量平衡。
