Photoperiod is the proximate cue which times the reproductive period of the sheep and the role of daylength as a "zeitgeber" is evaluated in this report. Although sheep are regarded as a short-day breeding species, the reproductive period of the Suffolk ewe begins on daylengths which are on average 2.5 hours longer than those on which it ends. The reasons for this apparent anomaly are considere...

The seasonality of reproductive activity in the ewe in temperate latitudes is controlled by photoperiod. Its annual variations control the temporal organization of the sexual cycle by changing the activity of the gonadotrophic axis. Cyclic oestrous behaviour usually appears in the ewe at the end of summer or the beginning of autumn and finishes in winter or at the very beginning of spring. Seas...

BACKGROUND In southern Africa, various options to manage elephant populations are being considered. Immunocontraception is considered to be the most ethically acceptable and logistically feasible method for control of smaller and confined populations. In this regard, the use of gonadotropin-releasing hormone (GnRH) vaccine has not been investigated in female elephants, although it has been repo...

The structural and ultrastructural modifications of the gonadotropic cells of goats were studied with an immunohistochemical method (peroxidase-antiperoxidase), in anoestrus, gestation and milk production. The cell type which predominates in anoestrus corresponds in its morphological characteristics to the classic FSH cells, and has two populations of homogeneous and electrodense secretory gran...

The clinical incidence of reproductive disorders in crossbred (local non-descript crossed with Friesian) was determined from the records maintained at the artificial insemination (A.I.) component, Livestock and Dairy Development Department, Balochistan for the period from July 1980 to June 1995. A total of 21 ,493 cases of uterine infections, reported anoestrus and obstetrical problems were rec...

The buffalo is considered as sluggish breeder as the reproductive efficiency of buffalo is adversely affected by certain constraints such as late maturity, poor expression of the estrous signs particularly during summer, irregular estrous cycle, silent heat, seasonality in breeding, poor conception rate/early embryonic mortality and prolonged inter-calving interval. Buffalo reproduction in trop...

It is well known that buffaloes have seasonal anoestrus and the use of melatonin reduces effects season in reproduction, articularly among sheep goats. This study evaluates on water to increase pregnancy rates a fixed-time insemination programme. The was conducted an Argentinian buffalo herd, located Corrientes Province, during unfavourable reproductive season. Artificial cycles were performed ...

Parturient goats rapidly develop exclusive nursing of their own litter that relies on olfactory recognition of the young. They also show a period of postpartum anoestrus whose duration depends on the presence of the kid. In cattle, maternal selectivity is one of the factors that delays the recovery of sexual activity. To investigate the possible influence of maternal selectivity on the duration...