Cushman R A, Davis P E, Boonyaprakob U, Hedgpeth V S, Burns P J, Britt J H
Department of Anatomy, Physiological Sciences, and Radiology, North Carolina State University, Raleigh 27606, USA.
J Anim Sci. 1999 Nov;77(11):2883-5. doi: 10.2527/1999.77112883x.
We determined whether a single injection of slow-release estradiol-17beta (SRE2) would induce pseudopregnancy in gilts and whether PGF2alpha would regress the corpora lutea (CL) of pseudopregnancy. Crossbred gilts (n = 40) were induced to ovulate by treatment with 400 IU of hCG + 200 IU of eCG (PG600, Intervet, Millsboro, DE) given at 180 d of age (d = 0). On d 14, gilts were injected i.m. with one of five doses (n = 8 gilts/dose) of SRE2 (0, 12.5, 25, 50, or 100 mg). Blood samples were collected before SRE2 and twice weekly until d 73 to monitor serum progesterone (P4) and estradiol (E2). On d 59, gilts received (i.m.) 10 mg of PGF2alpha (Lutalyse, Pharmacia Upjohn, Kalamazoo, MI) and were checked for estrus for 7 d. On d 62, mammary development was scored (0 = no development; 1 = some development; 2 = teat and gland development) by a neutral observer. Treatment with SRE2 increased (P < .05) peak E2 concentrations, duration of luteal function, and mammary gland score. There were no differences (chi-square, P > .05) among doses of SRE2 in the percentage of pseudopregnant gilts that showed luteolysis after PGF2alpha. We conclude that a single injection of SRE2 can induce pseudopregnancy and that the CL can be regressed with PGF2alpha, providing a simple method for controlling estrus in gilts.
我们研究了单次注射缓释β-雌二醇（SRE2）是否会诱导后备母猪假孕，以及前列腺素F2α（PGF2α）是否会使假孕的黄体退化。选用40头杂种后备母猪，在180日龄（第0天）时，用400 IU人绒毛膜促性腺激素（hCG）+200 IU孕马血清促性腺激素（eCG）（PG600，英特威，米尔斯伯勒，特拉华州）诱导排卵。在第14天，给后备母猪肌肉注射5种剂量（每种剂量8头）之一的SRE2（0、12.5、25、50或100 mg）。在注射SRE2前采集血样，之后每周采集两次，直至第73天，以监测血清孕酮（P4）和雌二醇（E2）水平。在第59天，给后备母猪肌肉注射10 mg PGF2α（氯前列烯醇，法玛西亚普强，卡拉马祖，密歇根州），并检查7天的发情情况。在第62天，由一名中立观察者对乳腺发育进行评分（0 = 无发育；1 = 有一些发育；2 = 乳头和乳腺发育）。SRE2处理使峰值E2浓度、黄体功能持续时间和乳腺评分增加（P < 0.05）。PGF2α处理后，不同剂量SRE2组假孕后备母猪黄体溶解的百分比无差异（卡方检验，P > 0.05）。我们得出结论，单次注射SRE2可诱导假孕，且PGF2α可使黄体退化，这为控制后备母猪发情提供了一种简单方法。
