Comparative quantitative assessment of GnRH- and LH-receptor mRNA expression in the urinary tract of sexually intact and spayed female dogs.

Ovariectomy interrupts the regulatory loop in the hypothalamus-pituitary-gonad axis, leading to a several-fold increase in gonadotropin levels. This rise in hormonal secretion may play a causal role in ovariectomy-related urinary incontinence. The purpose of this study was to examine the effect of ovariectomy in bitches on the expression of GnRH- and LH-receptors in the lower urinary tract, and assess the relationship between receptor expression and plasma gonadotropin concentrations. Plasma gonadotropins were measured in 37 client-owned bitches. Biopsies were harvested from the mid-ventral bladder wall in all dogs, and from nine further locations within the lower urinary tract in 17 of the 37 animals. Messenger RNA of the LH and GnRH receptors was quantified using RT-PCR with the TaqMan Universal PCR Master Mix. Gonadotropins were measured with a canine-specific FSH-immunoradiometric assay and LH-radioimmunoassay. The hierarchical mixed ANOVA model using MINITAB, Mann-Whitney U-test, unpaired means comparison and linear regressions using StatView were applied for statistical analyses. Messenger RNA for both receptors was detected in all biopsy samples. Age was negatively correlated to mRNA expression of the LH and the GnRH receptors. A relationship between the mRNA values and the plasma gonadotropin concentrations was not established. Evaluation of results within each of the biopsy locations revealed greater LH-receptor expression in the proximal second quarter of the urethra in spayed bitches than in intact bitches (P=0.0481). Increased mRNA expression of LH receptors in this location could possibly play a role in the decrease in closing pressure of the urethra following ovariectomy.

Review of contraception in ungulate species.

Most ungulate species are herd animals. In captivity, and increasingly so in the wild, space constraints limit natural behaviors associated with group dynamics, possibly resulting in inbreeding and/or overpopulation. This situation has necessitated research regarding contraception of various species of hoofstock. Differing management situations mandate different contraception protocols to achieve optimal results. Fertility control in hoofstock has been achieved through a number of different contraceptive methods predominantly surgical sterilization, mechanical contraception, synthetic steroid hormones, and immunocontraception. In this study successes and limitations of these techniques are reviewed. Zoo Biol 26:311-326, 2007. (c) 2007 Wiley-Liss, Inc.

Controlled-release products for the control of the estrus cycle in cattle, sheep, goats, deer, pigs, and horses.

This paper describes the estrus cycles of a number of livestock breeds and reviews the controlled-release drug delivery systems that are currently available for the purpose of controlled breeding. The bovine estrus cycle is reviewed in detail, and the estrus cycles of other species are described in a manner that highlights similarities and differences between species. Pertinent formulation and pharmacokinetic information about current drug delivery systems is presented and discussed, and recent advances in this area are also described.

Mensus-inducing drugs: their role in antique, medieval and renaissance gynecology and birth control.

PIP: Antique medical texts describe the use of menses-inducing drugs; some drugs were used for abortions as well as for treating amenorrhea. A table presents a list of these drugs; 71 of the 161 drugs quoted are not now known for causing abortion. A safe and effective once a month pill was first described by Soranus and is still considered an important goal for modern birth control.^ieng

Forty years of control of the oestrous cycle in ruminants: progress made, unresolved problems and the potential impact of sperm encapsulation technology.

Pharmacological control of the oestrous cycle may, with or without sperm encapsulation, remain an indispensable part of any attempt to make artificial insemination available to the ranch-cattle industry. Of the current methods, those most likely to remain acceptable with regulatory agencies and to gain acceptance with industry are those involving the short-term use (7-10 days) of minimal effective doses of progestins (preferably progesterone) and the subsequent use of an analogue of prostaglandin F2 alpha. The use of microencapsulated sperm with a long lifespan would allow artificial insemination to be achieved without reference to the time when heat and ovulation may occur.

Clinical evaluations of a new prostaglandin analog in pigs: 1. Control of parturition and of the MMA-syndrome.

In two field trials, the parturition inducing and MMA preventing effects of the prostaglandin F(2alpha) analog (PGFA), K 11941, were explored. In trial 1, 100 sows were treated with 2 mg and 30 with 3 mg of K 11941 i.m. on day 112 of gestation; 125 sows treated on day 112 with 175 mcg cloprostenol (Planate, ICI) served as positive controls, and 248 sows treated with saline on day 112 of gestation were used as negative controls. Both PGF analogs were equally effective in inducing early parturiton: 84.6% and 83.2% of the sows had farrowed between 20 and 30 hours after treatment. Both treatments reduced stillbirth rate and piglet losses during the first 10 days of life, and lowered the incidence of MMA significantly (6.2 and 5.6% vs 27.3 and 24.2%; p<.001). In a second trial, parturitions were induced in four groups of 60 sows each with 2 mg K 11941, housed in farms with either a chronic high incidence of MMA (A: 45 to 65% or only a seasonal rise in MMA during summer (B: 10 to 50%). Groups were treated either in April/May or August/September; 240 salinetreated, control sows were used. K 11941-induced parturition reduced MMA incidence in farm A during both seasons and prevented the summer rise in farm B (p<.01). Fertility after weaning was impaired in herds with an increased incidence of MMA.

Clinical evaluation of a new prostaglandin analog in pigs: 2. Prophylaxis and therapy of anestrus after weaning in sows and first litter gilts.

Alfaprostol, a new prostaglandin F2alpha (PGF) analog was given in a first trial at two dose levels known to be luteolytic (1 and 2 mg) to 200 sows and first litter gilts at the day of weaning after a 21-day lactation period; 189 controls received saline only. The treatment with alfaprostol shortened the interval to heat (6.0 vs 11.3 days; p<0.01) and increased the percentage of animals coming into heat within 10 days (84.0 vs 65.5%; p<0.01). Fertility to a.i. and litter size at the subsequent parturition were normal. In a second trial, 100 first litter gilts and 100 sows received alfaprostol, 1 or 2 mg, respectively, during July and August when high environmental temperatures tend to increase the rate of anestrus. Again, treatment with alfaprostol shortened effectively the interval to heat (5.9 vs 17.4 days in gilts, p<0.001; 5.6 vs 9.7 days in sows; p<0.01) and greatly increased the number of animals in heat (81 vs 47% in gilts, 83 vs 62% in sows; p<0.001). The effect on the seasonal incidence of clinical anestrus was marked; it was more pronounced in gilts than in sows, expressed by the length of time it took to resume cyclic functions and the lower percentage of animals coming into heat (p<0.001). The effect of alfaprostol was equally well expressed in first litter gilts and sows. In a third trial, 295 anestrous sows and gilts were treated on day 22 after weaning with either 2 mg alfaprostol, or 400 I.U. PMSG+200 I.U. hCG, or saline. Within five days after weaning, 38% of the alfaprostol treated, and 78% and 23% of the animals treated with PMSG/hCG and saline came into heat.

Estrous cycle synchronization in dairy heifers with the prostaglandin analog alfaprostol (I).

The prostaglandin F(2alpha) analog (PGFA) alfaprostol was used in 277 cyclic dairy heifers for the purpose of estrous cycle synchronization. A dose of 5 mg was used in all the trials during spring 1979 and 1.5 mg 100 kg body weight were used during winter 1979/80. Animals were treated according to 3 schedules: two doses 11 days apart without prior examination (Schedule I), one dose without prior observation and a second dose 11 days later only for those animals that failed to show estrus after the first treatment (Schedule II) and one dose for animals not showing estrus after a 5-day observation period (Schedule III). Estrus synchronization was achieved with peak estrus activity occurring form 32 to 72 h after treatment in 95% of the responding animals. Of the animals treated according to schedules I, II and III, 93%, 100% and 100% showed synchronized estrus activities respectively. Conception rates in all trials, from insemination at observed heat (Schedules I, II and III) or from fixed time insemination at 48 and 72 h after the first or second treatments in schedules III and I, respectively, compared well with that of untreated contemporary controls with a range of 34.2 to 66.7% for animals in these trials, and an overall conception rate of 49.48% for treated and of 48.30% for control animals. This observation, together with the pregnancy rate at 60 days after breeding (78.30% for all treated animals and 73.50% for all untreated controls), indicates that alfaprostol had no adverse effects on fertility.

Estrous cycle synchronization in dairy heifers with the prostaglandin analog alfaprostol (II).

Over a two year period, 276 dairy heifers (German Black Pied x Holstein Friesian) received one or two injections i.m. of 1.5 mg/100 kg body weight of the PGF analog alfaprostol. Only animals not showing heat after the first injection were treated twice, with the same dose, 11 days apart. Before treatment, 71% of the heifers were cycling regularly, 12% were cycling irregularly and 17% were not observed in heat prior to treatment. Animals in heat were inseminated once or twice, 18 to 24 h apart. In response to the first injection, 60.5% of all treated animals came into heat; 38% showed heat after the 2nd treatment. Three of the six non-responding animals were later diagnosed as freemartins. Heat was well synchronized. Twenty seven percent, 60% and 9% of all first inseminations occurred on days two, three and four after treatment (s), respectively; 65% of all heifers conceived from the first insemination. Pregnancy rates after one or two inseminations were 66.0% and 63.8%, respectively. At the second a.i., 45% of all animals had already ovulated. Pregnancy rates from first a.i. after one or two treatments with alfaprostol were 60.1% and 72.2%, respectively. Years had no influence on any of the parameters observed. Stage of cycle in which the first treatment occurred had a strong influence on the occurrence of heat and on conceptions as well. Of the animals treated between days 6 and 18% of their cycles, 92.6% responded with heat to the first treatment and 79% conceived. When animals were treated for the first time between days 19 and 5 of their cycles, only 28.8% came into heat and only 23.8% conceived. After the 2nd treatment, 71.2% of the latter group came into heat and 73.1% conceived.

Delayed termination of third-trimester gestations in dairy cows after treatment with the PGF(2alpha)analog Tiaprost.

Six dairy cows of the German Black Pied breed were treated between days 190 and 266 of gestation with 0.75 mg of the PGF(2alpha) analog Tiaprost (Iliren(R)-Hoechst). Luteolysis occurred within 24 hours, with progesterone blood levels dropping to baseline values of about 3.18 nmol/l (l ng/ml), but pregnancies were terminated by spontaneous abortions or premature parturitions only after an average of 24.2 days (range 5 to 50 days) after treatments. Four of six deliveries were premature and all deliveries were preceded by a rise in blood estrogen levels which commenced 1 to 12 days prepartum and peaked intrapartum. Unsuccessful attempts were made to induce this estrogen rise earlier by using treatments with Tiaprost, PGF(2alpha)-THAM or estradiol benzoate; treatments with a progesterone-releasing intravaginal device did not prevent the estrogen rise. Abortions and parturitions were spontaneous or by slight pulling. The placenta was retained in all six animals. Two immature fetuses were stillborn, and one immature born calf died three hours after birth.

Induction of parturition in swine with a prostaglandin analog and oxytoxin: A trial involving dose of oxytocin and parity.

The purpose of this experiment was to compare a range of oxytocin doses in order to find the most suitable dose to improve predictability and precision of timing of PGF-induced parturition in sows. Sows randomly allotted to 6 groups - group size varying between 28 and 39 - were either untreated controls (group 1) or received an IM injection of 2 mg of the PGF-analog Alfaprostol (Vetem) on day 111 of pregnancy (day 0 = last day of standing heat), followed 20 h later by 0, 5, 10, 20 or 30 IU oxytocin, respectively (groups 2 - 6). Both length and variability of the time from injection of oxytocin to the onset of parturition decreased with increasing dose. The response was faster and more predictable with older sows than with first litter gilts. A disadvantage of higher doses of oxytocin was the necessity of manual aid (11 % in controls, 52 % with the maximum level of 30 IU oxytocin). Litter size, weight and percentage of piglets weaned and time from weaning to subsequent estrus were not affected by any of the treatments. An oxytocin dose of 20 IU applied 20 h after PGF appeared to give the most effective response, although this will occasionally necessitate manual assistance with parturition.

Inhibition of lactation in the Beagle bitch with the prolactin inhibitor cabergoline (FCE 21336): Dose response and aspects of long-term safety.

Sixteen healthy, lactating Beagle bitches with litters of three to six pups were assigned to four treatment groups for one daily oral treatment of cabergoline in an oily solution (0, 1.25, 2.50 or 5.0 mcg/kg body weight (BW) for 5 d, commencing on Day 8 of lactation. Bitches and all their puppies were weighed daily for 2 d before treatments started, and for 10 d thereafter. Technicians rated daily treatment effects on maternal health, maternal behavior and mammary glands, using a scoring system. Treatments had no effect on maternal health, maternal body weight, and maternal behavior. Treatments with the two higher doses caused a reaction and a regression of the mammary glands in a dose-related fashion, resulting in cessation of lactation with 5 mcg/kg BW. Maternal treatment did not adversely affect the puppies' health, and no puppy was lost during the trial. However, average daily weight gains of puppies declined with increasing levels of cabergoline, causing significant weight losses in the 2.5 and 5 mcg/kg treatment group. This became evident after 2 d of treatment. To save the puppies in the highest dosage group, hand-feeding, and later, crossfostering, had to be used with all litters, starting on Day 3 or 4 of treatment. Weight losses were dose-related with an ED(50) of 1.5 mcg/kg/d and persisted for at least 24 h after treatment had ceased. Since puppies were left with their mothers to provide a continued suckling stimulus, lactation rebounded in all bitches treated with 2.5 mcg/kg, but only in two of four bitches treated with 5 mcg/kg. All bitches returned to estrus at their normal intervals. Fertility and fecundity at the next breeding were undisturbed.

Techniques developed for the control of estrus, ovulation and parturition in the East German pig industry: a review.

Centralized administration of the nationalized pig industry in the former German Democratic Republic (East Germany), promoted wide-scale use of assisted reproduction of pigs. The objective was to synchronize reproductive events such as estrus, ovulation, breeding and parturition in a way that would allow for quick penetration of desirable genetic information by timed artificial insemination and the routine use of hygienic measures. Methods developed to control these events were based on extensive basic and applied research, but the resulting pool of unique scientific information was heretofore not published in refereed journals in the English language. We present here a comprehensive review of biotechnological procedures and physiological insights gained by basic and applied research and by their application at the large pig production units.

Control of ovulation with a GnRH analog in gilts and sows.

Methods for the control of ovulation with GnRH or the GnRH analog D-Phe6 -LHRH (GnRH-A), were evaluated in gilts and sows as the last step in development of a fixed-time Al protocol. This involved 3 field trials using 2,744 gilts (10 units) and 71,628 sows (33 units). In Trial 1, the GnRH-A (75 microg) was given subsequent to treatment with altrenogest for cycle control or eCG for the stimulation of uniform follicle development in gilts. The release of LH was followed by ovulations which commenced within 36.4 +/- 3.3 hr and were terminated at 39.0 +/- 2.8 hr after administration of GnRH-A. This degree of synchronization of ovulations enabled the use of fixed-time AI. Consequently, subsequent to pretreatment with altrenogest and eCG, in 10 production units 1,285 gilts received 50 microg GnRH-A and 1,459 gilts 500 IU hCG serving as positive controls (Trial 2); all the gilts were inseminated 24 and 42 hr after treatment. Pregnancy rate and piglet index (n of piglets per 100 first inseminations) following GnRH-A vs hCG were 78.8% and 779 vs 74.4% and 728, respectively (P < 0.05). In field trials with first litter gilts and multiparous sows (33 units holding from 250 to 6,000 sows), 1,000 IU eCG was used for estrus control after weaning and 25 microg or 50 microg GnRH-A were given 55 to 58 hours after eCG (n = 19,954 and 20,701) (Trial 3). Sows treated during the same time period with 300 microg GnRH plus 300 IU. hCG (n = 30,973) served as positive controls; all sows were inseminated 24 and 42 hours after treatment. Pregnancy rates for 50 microg GnRH-A, 25 microg GnRH-A and 300 microg GnRH plus 300 IU hCG were 83.0%, 81.7% and 80.7%, and the piglet indices 913, 899 and 880, respectively (P < 0.05). Unit size and parity had significant effects on fertility and productivity. In all studies, results with 50 microg GnRH-A were superior. In year-long studies, highest levels of fertility in response to these treatments were seen from December to May.

Mestranol as an abortifacient in the bitch.

PIP: For 20 or more years it has been known that a single oral dose of 5 mg mestranol (17alpha-ethinylestradiol-2 methyl ether) is effective for preventing conception in the beagle 95% of the time when administered 1-5 days after mating. This study administered a single oral dose of 4.5, 1.5, or .5 mg on Day 5 after mating to 7 young beagle bitches. All were sacrificed on Days 21-28 after mating, the second trimester of pregnancy in this species. 5 of the 7 animals (those receiving .5 and 1.5 mg) had uteri containing degenerate embryos. In 1 animal receiving 1.5 mg, embryos had already disappeared. 1 bitch receiving 4.5 mg was probably not pregnant. In each instance the embryos were free-floating in the lumen of the uterus due to failure of placental attachment and were either retarded or degenerating. Histologically, the innermost lining of the maternal placenta was disrupted in focal areas with the aseptic lesion containing debris and necrotic cells. Areas between such disrupted areas were lined by the thickened wall of the blastocyst, suggesting resorption of the embryos. Plasma progesterone levels rose during the first trimester according to the pattern for beagles, indicating mestranol had no visible effect on ovarian progesterone production. The tentative conclusion is that mestranol dose not interfere with fertilization or early embryonic development but rather with implantation, resulting in resorption of degenerating embryos.^ieng

Luteolysis and cycle synchronization with a new prostaglandin analog for artificial insemination in the mare.

Over a period of three years, 165 cyclic or anestrous Hanoverian mares received 177 treatments with 2, 3 or 4 mg of a novel luteolytic prostaglandin analog, K 11941. Heat and ovulations, indicating luteolysis, were observed after an average of 3.98 and 7.62 days, respectively, in 88.04% of 142 treated cyclic, postpartum and anestrous mares, and mares after an early loss of the conceptus. All doses tested were effective in inducing luteolysis as confirmed by determination of progesterone blood levels in samples collected daily, in 70 of 80 mares studied (87.5%). Attempts to achieve control of the cycle by various methods revealed that with K 11941 given once or twice, alone or in combination with hCG and/or an GnRH analog (Hoe 766), one can effectively concentrate estrus periods and follicular growth patterns, but can neither synchronize nor concentrate ovulations. Since most of the mares treated were confirmed problem mares, the pregnancy rate of 40.0% from first insemination at drug induced estrus, was regarded as satisfactory when compared to a pregnancy rate of 43.8% obtained with natural breeding in the same population. No drug related clinical signs of side-effects were observed.

Superovulation of beef heifers with Pergonal (HMG): A dose response trial.

A study was designed to establish a dose-response curve for Pergonal (Human Menopausal Gonadotrophin) and to compare its efficacy in inducing superovulation with commercial FSH-P. A recognized treatment schedule for HMG of two ampoules at 0, 12, 24 and 36 hours and one ampoule at 48, 60, 72, 84, 96 and 108 hours was considered to be our 100% effective dose level. Fifty mature cycling cross-bred beef heifers were superovulated on day 10 +/- 1 of their cycle. Treatment groups were HMG I (200% dose), HMG II (100% dose), HMG III )50% dose), HMG IV (25% dose) and FSH-P (total dose 32 mg). All groups received 500 ug of cloprostenol 72 hours after initiation of treatments. The heifers were observed for onset of estrus and inseminated at 12, 24 and 36 hours. All heifers were slaughtered on day 7 post-estrus and their reproductive tracts removed for processing. All heifers were bled once daily for progesterone estimation and four times daily for two days beginning 24 hours after cloprostenol injection, for luteinizing hormone and estradiol-17beta estimations. A dose response to HMG was demonstrated for number of corpora lutea and all classes of ova/embryos. HMG II (100% dose) closely approximated the optimum dose for superovulation. There was no significant difference between the HMG II group and the FSH-P group for mean number of transferable embryos. The 200% HMG dose did not increase the numbers of ovulations or ova recovered but did decrease the numbers of fertilized and transferable ova.

The effect of GnRH analogs on urinary incontinence after ablation of the ovaries in dogs.

After removal of the ovaries approximately 20% of dogs develop urinary incontinence. Removal of the gonads results in estrogen deficiency and chronic elevation in the production and secretion of FSH and LH. The gonadotrophins may directly or indirectly, adversely affect the sphincter function of the urethra. Estrogen replacement therapy and treatment with sympathomimetics, such as ephedrine or phenylpropanolamine (PPA), are effective only in some of the affected dogs, and many of these subsequently become nonresponsive. Since the role of the elevated gonadotrophins has not been elucidated, we used depot preparations of GnRH analogues to down-regulate gonadotrophins once or twice in 13 ovariectomized (ovx), incontinent dogs, which were either refractory to alpha-adrenergics (n=11) or in which alpha-adrenergics were contraindicated (n=2). Dogs were treated with leuprolide, deslorelin, buserelin or triptorelin. In 7 dogs treatments with GnRH analogues alone (n=11) resulted in continence for 50-738 days (mean 247). In all dogs except one, where GnRH treatments did not resolve the incontinence completely, additional treatment with phenylpropanolamine was successful. With additional treatment of phenylpropanolamine complete continence was restored for 21-367 days (mean 159). All treatments caused long-term reduction of circulating FSH and LH concentrations to very low or undetectable levels. No adverse effects of treatments were observed.