altrenogest and Body-Weight

Oral administration of altrenogest for oestrus suppression in competition horses is believed to be widespread in some equestrian disciplines, and can be administered continuously for several months during a competition season. To examine whether altrenogest has any anabolic or other potential performance enhancing properties that may give a horse an unfair advantage, we examined the effect of oral altrenogest (0.044 mg/kg), given daily for a period of eight weeks, on social hierarchy, activity budget, body-mass and body condition score of 12 sedentary mares. We concluded that prolonged oral administration of altrenogest at recommended dose rates to sedentary mares resulted in no effect on dominance hierarchies, body mass or condition score.

Topics: Administration, Oral; Anabolic Agents; Animals; Behavior, Animal; Body Constitution; Body Weight; Doping in Sports; Female; Horses; Social Behavior; Social Dominance; Time Factors; Trenbolone Acetate

Oral administration of altrenogest for oestrus suppression in competition horses is believed to be widespread in some equestrian disciplines, and can be administered continuously for several months during a competition season. To examine whether altrenogest has any anabolic or other potential performance enhancing properties that may give a horse an unfair advantage, we examined the effect of oral altrenogest (0.044 mg/kg), given daily for a period of eight weeks, on social hierarchy, activity budget, body-mass and body condition score of 12 sedentary mares. It was concluded that prolonged oral administration of altrenogest at recommended dose rate to sedentary mares had no effect on dominance hierarchies, body-mass or condition score.

Topics: Administration, Oral; Anabolic Agents; Animals; Behavior, Animal; Body Constitution; Body Weight; Doping in Sports; Female; Horses; Social Behavior; Social Dominance; Time Factors; Trenbolone Acetate

Horse mares are frequently treated with the progestin altrenogest with the aim to suppress estrous behavior and its negative impact on equestrian performance. Progestogens, however, also have sedative effects in males, and females of different species. The aim of our study was therefore to investigate altrenogest-induced changes in the stress response of female horses during initial equestrian training. Three-yr-old Warmblood mares were randomly assigned to treatment with altrenogest (ALT; 0.044 mg/kg once daily; n = 6) or sunflower oil (CON; n = 5) for 12 wk during training. At predefined steps of the training program (free movement, lunging without and with side reins, lunging with saddle, mounting of a rider, free riding, riding by an unfamiliar rider) salivary cortisol concentration, and heart rate were determined from 60 min before to 120 min after training. The same procedures were performed during repeated gynecologic examinations and 2 novel object tests. Bodyweight and body condition scores (BCS) were assessed at 4-wk intervals. During all training units, salivary cortisol concentration and heart rate increased (P < 0.001), but the increase was smaller in group ALT mares (time x treatment P < 0.001). Gynecologic examinations and novel object tests induced a much smaller increase in cortisol and heart rate (P < 0.001) than equestrian training with no difference between groups ALT and CON. Initially, bodyweight, and BCS decreased during training. The subsequent increase was larger in group ALT vs CON (time x treatment P < 0.05). In conclusion, altrenogest reduced the stress response of 3-yr-old mares to equestrian training. The use of altrenogest during equestrian competitions should therefore be reconsidered.

Topics: Animals; Body Weight; Female; Horses; Hydrocortisone; Male; Progestins; Trenbolone Acetate

The purpose of this study was to demonstrate that a barren parous Thoroughbred mare with lactation induced by hormonal treatment can be introduced to an orphan foal at the same farm and that the mare can become pregnant after the end of the hormonal treatment. An additional purpose was to investigate the changes in the plasma concentrations of prolactin, estradiol-17β, progesterone, follicle-stimulating hormone, and luteinizing hormone before, during, and after hormonal treatment. The difference in body weight between the adopted foal and the control foals, which were at the same farm and raised by their natural mothers, was 17 kg at 24 weeks old, when the foals were weaned. However, the adopted foal and the control foals had almost the same weight at 35 weeks old and later. The first ovulation after hormonal treatment was confirmed 10 days after the end of hormonal treatment and then the normal estrous cycle resumed. Furthermore, the changes in plasma progesterone, estradiol-17β, follicle-stimulating hormone, and luteinizing hormone showed regular patterns after the first ovulation. Conception was confirmed in the fifth ovulation. Meanwhile, another study demonstrated that conception was confirmed in the first ovulation after hormonal treatment. The present study is the first to demonstrate the hormonal profiles during and after induction of lactation in a Thoroughbred mare. This approach is useful for solving the economic and epidemic problems of introducing a nurse mare to an orphan foal.

Topics: Aging; Animals; Body Weight; Estradiol; Female; Horses; Insemination, Artificial; Lactation; Pregnancy; Prostaglandins; Sulpiride; Trenbolone Acetate

In this study, effects of altrenogest treatment (0.088 mg/kg daily) given to mares during late gestation until parturition on the time and the process of foaling, neonatal adaptation and postnatal development were analysed. The number of animals was 6 in the treatment group and 7 in the control group. Gestational length tended to be shorter in mares given altrenogest. Birth weight of the foals and weight of the placenta did not differ between groups. The second stage of parturition was prolonged in the altrenogest-treated mares (p<0.05). Foals born to altrenogest-treated mares had a significantly lower respiratory rate than control foals during the first 30 minutes of life (p<0.05). At no time differences in heart rate and body temperature were found between groups. In foals of altrenogest treated mares, venous plasma pH was significantly higher than in control foals at 15 and 30 minutes after birth (p<0.05). Base excess in foals of altrenogest treated mares was significantly higher than in control foals at 45 minutes and up to 12 hours after birth (p<0.05). There were significantly more problems in the perinatal period (3/6) in foals born after altrenogest treatment to their dams than in control foals (0/7; p<0.05). In conclusion, treatment with altrenogest did not prevent parturition and its effectiveness to prevent abortion or preterm foalings in mares with disturbed pregnancies should be doubted. In addition, altrenogest treatment of mares affected adaptation of the foals to the extrauterine environment.

Topics: Animals; Animals, Newborn; Birth Weight; Body Weight; Female; Fetal Death; Horses; Placenta; Pregnancy; Pregnancy Complications; Progesterone Congeners; Trenbolone Acetate

This study investigated the effects of feeding the orally active progestagen, altrenogest (Regumate) post-weaning on the subsequent reproductive performance of early weaned sows. Ninety (90) Large White/Landrace first parity sows were randomly assigned to three treatments. Treatment 1 (EW) and treatment 3 (CW) sows were weaned on day 12 and day 24 post-partum, respectively while treatment 2 sows (EW-R) were weaned on day 12 post-partum and received an individual daily dose of 20 mg of Regumate on days 13 to 24 post-partum inclusive. Each sow was mated naturally at least twice at the first post-weaning or post-treatment oestrus and slaughtered on days 25-28 of pregnancy to determine the number of corpora lutea and embryos. Regumate-to-oestrus and weaning-to-oestrus intervals were similar for EW-R and CW sows (6.2 vs. 5.6 days). However, both intervals were significantly shorter (P < 0.01) than the weaning-to-oestrus interval of EW sows (7.3 days). An excellent synchronization of oestrus was achieved with Regumate treatment with 97% of treated sows in oestrus within 7 days of Regumate withdrawal compared with 64% for EW sows (P < 0.01) and 87% for CW sows (P > 0.05). Treatment with Regumate resulted in a significant increase in ovulation rate (16.9 vs. 15.4 and 14.9 for treatments EW-R, EW and CW, respectively; P < 0.05) and a non-significant increase in early embryonic survival (77% vs. 68% vs. 68% for treatments EW-R, EW and CW, respectively; P > 0.05). These results indicate that Regumate feeding is a potential management tool to alleviate the diminished reproductive performance associated with early weaning regimes since it leads to successful control of oestrus, higher ovulation and embryo survival rates and thus a greater potential litter size.

Topics: Animals; Animals, Suckling; Body Weight; Crown-Rump Length; Estrus; Female; Fertility; Male; Ovulation; Parity; Pregnancy; Progesterone Congeners; Random Allocation; Swine; Trenbolone Acetate; Uterus; Weaning

Crossbred (Chester White X Yorkshire X Duroc) boars were used to evaluate the effects of feeding a progestogen (altrenogest) on body growth, endocrine function (determined during feeding and after withdrawal of altrenogest), carcass composition, boar odor and testicular function (determined after a 30-d withdrawal from altrenogest). Boars from 18 litters were assigned at 12 wk of age to three treatments: 1) 18 control boars; 2) 18 boars fed altrenogest (20 mg/day) for 6 wk from 15 to 21 wk of age, followed by 30 d with no treatment; and 3) 18 boars castrated at 2 wk of age (barrows). Daily gains were greater (P less than .05) in boars fed altrenogest than in barrows through 21 wk of age but were lower (P less than .05) than those of control boars and barrows during the 30-d withdrawal period. Boars fed altrenogest weighed less (P less than .05) than control boars and barrows at 25 wk of age (at slaughter). Both groups of boars were similar in percentage of muscle and had less (P less than .05) backfat than barrows, whereas control boars had the largest (P less than .05) loineye areas. Based on evaluations by a trained sensory panel, intensity of boar odor in fat samples was similar for both groups of boars and was greater (P less than .05) than that for barrows. Weights of accessory reproductive glands and weight and sperm content of testes and epididymides were reduced (P less than .05) in boars fed altrenogest.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Body Constitution; Body Weight; Estrenes; Follicle Stimulating Hormone; Luteinizing Hormone; Male; Odorants; Organ Size; Progesterone Congeners; Swine; Testis; Testosterone; Trenbolone Acetate

Analogues of prostaglandin F2 alpha are widely used in the United Kingdom to induce parturition in sows. A disadvantage is that sows are induced to farrow in advance of expected delivery dates. An alternative might be to maintain gestation by the application of a progestogen. Farrowing might then be initiated on the withdrawal of the progestogen. The use of an orally active progestogen (allyl-trenbolone) in an attempt to control the time of parturition in sows is described. In experiment 1, 20 large white cross landrace sows were allocated at random to one of two treatments. Treated sows were fed 16 mg/day of allyl-trenbolone from day 111 of gestation to day 118 of gestation. The farrowing performance of these sows was compared with that of control sows which farrowed naturally. Treated sows farrowed significantly (P less than 0.01) later than the control sows (118.2 and 116.1 days respectively). For treated sows the interval from progestogen withdrawal to farrowing was 29.6 +/- 4.8 hours. The number of stillbirths for treated and control sows respectively was 2.1 and 0.4 per litter. Treatment had no effect either on the birth weight of piglets or on their weaning weight at six weeks old. There was a tendency for more treated sows to show subsequent reproductive malfunction. In a second experiment, under commercial conditions, 81 sows and 12 gilts were allocated to one of four treatments. Treatment A animals were untreated controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Animals, Newborn; Body Weight; Estrenes; Female; Labor, Induced; Litter Size; Pregnancy; Swine; Trenbolone Acetate

A synthetic progestogen (altrenogest) was fed to 24 Yorkshire X Duroc boars to determine effects on body growth, serum testosterone, and testicular characteristics. Boars from six litters (blocks) were allotted randomly to one of four treatment groups at 12 wk of age. Treatment groups were: controls, altrenogest fed for 3 wk, altrenogest fed for 6 wk and altrenogest fed for 9 wk. Treatment began at 15 wk of age at a daily dose of 20 mg X boar-1. Although there were no differences among treatment groups for gain and feed intake, boars fed altrenogest for 6 and 9 wk tended to consume more feed and were less (P less than .05) efficient than boars fed altrenogest for 3 wk or controls. Boars fed altrenogest for 3, 6 and 9 wk maintained lower (P less than .05) peripheral serum testosterone concentrations than controls from 15 to 24 wk of age. However, serum testosterone increased after altrenogest withdrawal in the 3- and 6-wk treatment groups but did not reach control concentrations by 24 wk. Boars fed altrenogest for 9 wk maintained serum testosterone below 1 ng/ml during the treatment period. Despite lower concentrations of serum testosterone in altrenogest-treated boars, backfat thickness was similar to controls, perhaps suggesting a slight anabolic effect of altrenogest on nutrient partitioning. Testicular weights and volumes at 24 wk decreased (P less than .001) linearly with increased duration of altrenogest feeding. Serum testosterone and estradiol in testicular venous effluent at castration were lower (P less than .01) in altrenogest-treated boars than in controls. These data demonstrate that feeding altrenogest inhibits both testicular growth and steroidogenesis of boars without altering body growth or backfat thickness.

Topics: Animals; Body Weight; Estradiol; Estrenes; Male; Progestins; Swine; Testis; Testosterone; Trenbolone Acetate