Effect of termination of pregnancy or long-term progestogen exposure on subsequent estrous cycle length and concentration of progesterone in plasma of heifers.
نویسندگان
چکیده
An experiment was conducted to determine whether short estrous cycles following abortion of heifers between 70 and 75 d of gestation are due to factors associated with the previous presence of a conceptus or long-term exposure of the uterus and(or) ovaries to a progestogen. Fifty crossbred heifers were randomly allotted at estrus (d 0) to five groups: control (n = 10), pregnant (Preg.; n = 14), progestogen (norgestomet) implant (Norg.; n = 9), progesterone-releasing intravaginal device (PRID; n = 9), or hysterectomy (Hyst.; n = 8). Control heifers were injected during the mid-luteal phase of an estrous cycle with 25 mg prostaglandin F2 alpha (PGF2 alpha) and length of the subsequent estrous cycle was determined. Beginning 6 to 8 d after estrus, heifers in the Norg. or PRID groups were given norgestomet ear implants or intravaginal coils, respectively, every 10 d for 70 d. Heifers were hysterectomized 5 to 8 d after estrus. Seventy to 75 d after conception, progestogen treatment or hysterectomy, heifers were injected (i.m.) with 25 mg PGF2 alpha and the last norgestomet ear implants or PRIDs were removed. Interval from PGF2 alpha injection to first estrus (means +/- SE) ranged from 2.5 +/- .2 to 4.4 +/- .7 d (P greater than .05). Length of the first estrous cycle means +/- SE) following PGF2 alpha-induced luteolysis or progestogen withdrawal was shorter (P less than .01) for the Preg. group (8.2 +/- .4 d) than for the control, Norg. and PRID groups (21.5 +/- .6 d; 19.3 +/- 1.4 d; and 18.2 +/- 1.3 d, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
منابع مشابه
Ovulatory response of different GnRH analogues and subsequent corpus luteum lifespan in the presence of norgestomet in Holstein heifers
This study investigated the effect of GnRH analogues on inducing ovulation of dominant follicle (DF)and subsequent corpus luteum (CL) lifespan in the presence of norgestomet implant in Holstein heifers. Onday 6 to 8 of the estrous cycle (day 0 of the experiment), all heifers (n=15) received norgestomet implantfollowed by prostaglandin injection on days 0 and 1. On day 4, group 1 (n=4) and 2 (n=...
متن کاملSystemic progesterone concentration following human chorionic gonadotropin administration at various times during the estrous cycle in beef heifers.
In Trial 1, 26 heifers were allotted randomly to a control group or one of four groups to receive a single injection of 3,000 IU hCG on d 1, 4, 7 or 10 of an estrous cycle. Heifers next completed a nontreated cycle, and at their third estrus were reallotted to one of the five groups described previously. Estrous cycle length was extended in cycle 1 but was not altered during the nontreated cycl...
متن کاملLuteinizing hormone secretion after withdrawal of exogenous progestogen in heifers fed three levels of dietary energy.
As experiment was conducted with 15 Angus X Hereford heifers that were 16 mo of age at the time the experiment was initiated. The heifers were assigned randomly in equal numbers to be fed low (L), maintenance (M) or high (H) energy diets for 191 d. Overall average weight for heifers at the time the experiment was initiated was 294 +/- 6 kg. All heifers were exhibiting estrous cycles at regular ...
متن کاملEffect of Post-Mating GnRH Treatment onSerum Progesterone Profile and Conception Rate in Buffaloes
The present study was designed to investigate the impact of exogenous administration of GnRH (Receptal VET®, Intervet Pharmaceuticals Ltd., India) on serum progesterone profile and conception rates during mid luteal phase of estrous cycle in buffaloes. Estrus was induced using Cyclix 2 mL. i/m. (Intervet India Pvt. Ltd., India) and animals were bred naturally during observed estrus. The buffalo...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Journal of animal science
دوره 67 6 شماره
صفحات -
تاریخ انتشار 1989