Potential for fecundin to influence the reproductive performance of merino ewes in Western Australia.

Four experiments were conducted at different locations in Western Australia to evaluate the effectiveness of immunizing young (maiden, 1 1/2 year old) and adult Merino ewes with Fecundin to improve their reproductive performances. The ovulation rates of immunized maiden ewes was increased (0.06-0.30) above that of untreated ewes in both experiments 1 and 2. However, there were no significant improvements in the marking percentages for the immunized ewes with the differences between the untreated and immunized ewes ranging from -16.4 to 5.8%. In comparison with untreated ewes immunization 6 and 2 weeks before the start of joining depressed ewe fertility by 26.1% whereas immunization 8 and 4 weeks before the start of joining did not significantly affect fertility. The availability of oat grain ad libitum prior to parturition and during early lactation did not improve the survival of lambs born to immunized ewes. In experiments 3 and 4 immunization of adult Merino ewes increased their ovulation rates (0.41-0.63) above untreated controls and tended to increase the proportion of pregnant ewes which had multiple pregnancies (from -2.3 to 34.2%). The responses at the end of lambing were variable (from -19.8 to 37.5% lambs marked) with high lamb mortalities occurring in some experiments. There was no adverse effect on the reproductive performances following consecutive annual immunizations over 3 years and the absence of treatment for 1 year did not prevent a response in the following year.

Natural family planning.

It is now well accepted that a woman can conceive from an act of intercourse for a maximum of only about 7 days of her menstrual cycle. The reliability of natural family planning depends on identifying this window of fertility without ambiguity. Several symptomatic markers, cervical mucus and basal body temperature, have been used extensively and with considerable success in most women but failures occur. Ovarian and pituitary hormone production show characteristic patterns during the cycle. Urinary estrogen and pregnanediol measurements yield reliable information concerning the beginning, peak, and end of the fertile period, provided that the assays are accurate and performed on timed specimens of urine. We have developed such enzyme immunoassays for urinary estrogen and pregnanediol glucuronides that can be performed at home. In the early versions of the assays, enzyme reaction rates were measured by eye, but more recently, a simple photoelectronic rate meter has been used. The final problem to be solved is not technologic but whether women are sufficiently motivated to expend the same time and effort each day for 10 days a month, with less cost, on fertility awareness as they spend on making a cup of tea.

Use of a styrene-maleic anhydride copolymer as an adjuvant with testosterone-serum albumin immunogens and its application to increasing ovulation rate in the ewe.

A synthetic poly(styrene-maleic anhydride) copolymer of average molecular weight 470,000 potentiated a testosterone-binding antibody response during immunization of sheep with immunogenic testosterone-3-carboxymethyloxime-serum albumin conjugates. The copolymer had weaker immunostimulatory activity than Freund's complete adjuvant (FCA). The minimum effective dose of the copolymer was about 30 mg at which secondary but not primary immune responses could be detected by radioimmunoassay. There was a generally weak anamnestic response in immune sheep as secondary and teritary responses tended to decline promptly from peak values; tertiary antibody titres usually did not exceed secondaries. The use of the copolymer as a solution or emulsion had no apparent effect on its immunoadjuvant activity when administered intramuscularly but the soluble form was inactive when given intraperitoneally. The testosterone-binding antibody that was produced using either the copolymer or FCA had considerable sensitivity to deactivation by mercaptoethanol. The ovulation rate of a group of 20 Merino ewes following immunization with testosterone-serum albumin using the copolymer adjuvant was significantly higher than an equal group of untreated control ewes.

Failure of exogenous progestogens to block dexamethasone-induced prostaglandin F release from the uterus of the late-pregnant cow.

The effect of exogenous progesterone or megestrol acetate (MGA) on cervical extensibility and on the concentrations of prostaglandin (PG) F in utero-ovarian plasma and progesterone, estrone sulphate and unconjugated estradiol-17 beta concentrations in jugular plasma was studied over Days 238-242 in pregnant cows given intrafetal infusions of dexamethasone to induce premature delivery. All 11 cows used in the study were given continuous intrafetal infusions of dexamethasone at a rate of 3.3 mg/day to induce premature labor. Progesterone was infused continuously at a rate of 400 mg/day for 10 day into the jugular vein of 3 of 11 cows while another 3 were given MGA at a rate of 20 mg/day. In the cows given dexamethasone alone premature parturition was induced in 2.5-4.5 days and all calves were born alive and well. However, in the progestogen-treated cows, dexamethasone failed to induce premature delivery. The cervix of these cows remained firm and unyielding during the time of the progesterone infusion. Following the withdrawal of exogenous progestogens the cervix became soft and compliant and the cows delivered within 0.5-1.5 days, but only 2 of the 6 calves were alive at birth. Hormone changes in the cows given intrafetal infusions of dexamethasone included a marked rise in utero-ovarian PGF and a concomitant decline in jugular progesterone concentrations. Plasma concentrations of estrone sulphate and estradiol-17 beta showed a small increase before delivery. An increase in utero-ovarian PGF concentrations was also observed in all of the progestogen-treated cows, although there was considerable individual variation in the timing of the PGF surge. The plasma concentrations of estrone sulphate and unconjugated estradiol-17 beta levels in the progestogen-treated cows showed the same general trend, with the levels increasing within 1-2 days of starting the dexamethasone infusion and then falling before delivery.(ABSTRACT TRUNCATED AT 250 WORDS)

Antisera reactive directly to estrone sulfate.

Derivatives of estrone were prepared and linked to bovine serum albumin or its methyl-esterified form to produce immunogens which were effective in raising antisera to estrone sulfate. The most effective was estrone-3-methylphosphonothioate, electrostatically complexed with methylated bovine serum albumin. The ionically combined hapten functioned as an antigenic determinant as do covalently bound haptens when administered to sheep in emulsions with Freund's complete adjuvant. Estrone-3-phosphate covalently or electrostatically linked to bovine serum albumin also produced antisera reactive to estrone sulfate. Estrone sulfate itself, after electrostatically complexing to methylated bovine serum albumin and administration with Freund's complete adjuvant to sheep, was ineffective in producing antisera. The sera which had workable titres to estrone sulfate showed considerable cross-reaction with free estrone but was otherwise highly specific with little or no reaction with other steroid sulfates, glucosiduronates or other free steroids. Radioimmunoassay curves using [6,7-3H]-estrone sulfate were highly sensitive and were effective in the range of 5-250 pg estrone sulfate.

Release of prostaglandin F, regression of corpora lutea and induction of premature parturition in goats treated with estradiol-17beta.

Premature parturition was induced in five pregnant goats infused intravenously with 4.65-8.4 mg estradiol-17beta but not in one treated with 5.85 mg estradiol-17alpha. A single intramuscular injection of 12 mg estradiol benzoate (8.8 mg estradiol-17beta equivalents) was also effective. These doses were estimated to provide plasma concentrations of estradiol-17beta in the physiological range for animals at sponteneous parturition. Circulating plasma concentrations of progesterone decreased and lactogenesis occurred before all instances of induced parturition but no such changes resulted from infusion of estradiol-17alpha. Placental delivery was normal in all animals but neonates of more than 10 days prematurity were non-viable.

Changes in phospholipids of ram spermatozoa during migration through the epididymis and possible origin of prostaglandin F2alpha in testicular and epididymal fluid.

A study of the lipid composition of ram testicular and ejaculated spermatozoa was made in an attempt to resolve conflicting results in the literature. Testicular spermatozoa were found to contain more than double the amount of phospholipid present in ejaculated spermatozoa. Most phohpholipid components, including choline plasmalogen, decrease substantially in concentration during migration of the spermatozoa through the male reproductive tract. Phosphatidylserine, ethanolamine phosphoglycerides and cardiolipin components accounted for the greatest relative decreases in concentration, the former decreasing by approximately nine tenths. Of the phospholipid-bound fatty acids the most pronounced change occurs in palmitic during migration of spermatozoa through the reproductive tract. There is a net loss of approx. 500 mug of palmitic acid for every 10-9 spermatozoa. The loss of arachidonic acid was particularly interesting, and prompted a study of the prostaglandin content of testicular and epididymal fluids, since arachidonic acid can act as a precursor of prostaglandin. The concentration of prostaglandin F2alpha found in the testicular and epididymal fluid is considerably in excess of that found in venous plasma of the ram.