CONSTRAINTS LIMITING THE EFFICIENCY OF ARTIFICIAL INSEMINATION OF CATTLE IN BANGLADESH. The aim of the present study was to identify the factors that influence postpartum intervals to first detected luteal activity, first service and to conception, and the conception rates of cows in the artificial insemination (AI) programme in Bangladesh. A baseline survey (investigations 1, 2 and 3) was made...

A study was conducted to investigate the possibility of measuring the electrical conductivity (EC) of cow's milk as a practical and cost-effective means of determining oestrus in cows. Prostaglandin injections were used to synchronise the oestrous cycle of 15 cows. From the onset of oestrus, milk and blood samples were collected from each cow every 2nd day over a period of 22 days. A portable, ...

In non-pregnant goats, appreciable amounts of testosterone (2.1 ng/g) and 5 alpha-dihydrotestosterone (DHT, 0.8 ng/g) were present in the corpus luteum on Day 12 of the oestrous cycle. Significant (P less than 0.01, N = 18) veno-arterial concentration differences of testosterone were found across ovaries bearing corpora lutea. No such difference in testosterone concentration occurred across ova...

The strategic use of natural shade and iodine supplementation at the time of joining led to an improved fertility of tropical Merino ewes. This was most pronounced when ambient heat stress was greatest (p <O.Ol). A higher incidence of oestrus and a higher pregnancy rate in mated animals both contributed to the improved fertility. Heat' stress conditions experienced during summer in a tropical s...

Blood serum progesterone (P4) levels in donor cows and heifers at donor selection, superovulation, insemination and embryo recovery were investigated. Significant differences in P4 levels in the investigated donors during superovulatory oestrus insemination were observed. The cows with low levels of P4 at insemination (5.8 ± 1.7 nmol/l) showed a better yield and quality of embryos (P<0.01) comp...

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...