The purpose of the present study was to investigate whether the electrical resistance values of the cervical mucus and/or blood οestradiol-17β and progesterone concentrations at mating, after oestrous synchronisation during the anoestrous or oestrous period in ewes, are related to fertility. Oestrus was induced by medroxyprogesterone acetate-impregnated intravaginal sponges (Veramix, Upjohn, US...

The aim of the present study was to examine the distribution of oestrogen receptor alpha (ERα) in the uterus of sows with reproductive disturbances as well as to study the expression of ERα in relation to plasma oestradiol-17β (E2) and progesterone (P4) concentrations in the blood. Crossbred 3–4 parity Lithuanian White x Danish Landrace breed sows presenting various reproductive disturbances we...

The expression of oestrus in ewes may be influenced by previous nutritional *history. Smith (1966) reported that restricted nutrition during the spring delayed or reduced the expression of oestrus in Merino ewes during the following autumn, even though nutrition had been improved and ewe live weights had recovered before the rams were introduced. Hunter (1962) and Smith (1962) have also suggest...

Mating has been shown to have effects on ovulation in a number of species which ovulate spontaneously, such as rats (Aron, Asch & Asch, 1961; Aron, Asch & Ross, 1966; Zarrow & Clark, 1968) and sheep (Parsons, Hunter & Rayner, 1967; Van der Westhuysen, Van Niekerk & Hunter, 1970). In the sow, the results obtained by Pitkjanen (1955) and Lebedev (1957) suggest that mating hastens ovulations and s...

A study was done to evaluate the effect of using progesterone (P4) intravaginal device (CIDR: controlled internal drug-releasing dispenser) to synchronise the return to oestrus of previously timed inseminated (TAI) dairy heifers, and to evaluate embryo survival and pregnancy rate (PR) in the return to oestrus heifers. At the onset of the artificial insemination (AI) breeding period (day -9), he...

The kisspeptin/Gpr54 signaling pathway plays a critical role in reproduction by stimulating the secretion of GnRH, yet mice carrying mutations in Kiss1 (which encodes kisspeptin) or Gpr54 exhibit partial sexual maturation. For instance, a proportion of female Kiss1−/− and Gpr54−/− mice exhibit vaginal oestrus, and some male Kiss1−/− and Gpr54−/− mice exhibit spermatogenesis. To characterise thi...

A total of 16 crossbred repeat breeder cows were treated with norgestomet (Syncromate-B) ear implants for nine days. At the time of implant insertion, two ml of SMB injection was adminisetred to all the cows intramuscularly on day 10 of the oestrous cycle to induce oestrus. AI was done at 48 and 72 h after implant removal. Pregnancy diagnosis was done at 60 days following AI after induced oestr...

The effects of acceleration and delay of puberty in female house mice on survival and reproduction were tested using 6 experimental groups: (1) control females mated at the time of first oestrus, (2) females mated at weaning, (3) females treated with male urine starting at weaning and mated at first oestrus, (4) females housed in groups and mated at first oestrus, (5) females housed alone, trea...

In October, 1964, beef cows were divided into three groups. One group was run with bulls for four months (group 1); another group was kept free of bulls and was observed daily for six weeks and cows detected in oestrus were inseminated using chilled semen (group 2); and the third group was given progestagens to synchronise ovarian cycles and the cows were inseminated after treatment and again a...

The effects of prostaglandin F2\g=a\on peripheral plasma progesterone and oestrogen levels, incidence of oestrous cycle alteration, and fertility were examined in thirty beef heifers. The PGF2\g=a\was administered by insertion of an insemination pipette into the lumen of the uterus during three periods of the oestrous cycle: Days 3 to 5, Days 9 and 10, and Days 16 and 17. Oestrus occurred withi...