Seasonality of reproduction and production in farm fishes, birds and mammals

Abstract

A very large majority of farm animals express seasonal variations in their production traits, thus inducing seasonal availability of fresh derived animal products (meat, milk, cheese and eggs). This pattern is in part the consequence of the farmer's objective to market his products in the most economically favourable period. It may also be imposed by the season-dependent access to feed resources, as in ruminants, or by the specific requirements derived from adaptation to environmental conditions such as water temperature in fish. But seasonal variations in animal products are also the consequence of constraints resulting from the occurrence of a more or less marked seasonal reproductive season in most farm animal species including fish, poultry and mammals. Like their wild counterparts, at mid and high latitudes, most farm animals normally give birth at the end of winter-early spring, the most favourable period for the progeny to survive and thus promote the next generation. As a consequence, most species show seasonal variations in their ovulation frequency (mammals and fish: presence or absence of ovulation; birds: variations or suppression of laying rates), spermatogenic activity (from moderate to complete absence of sperm production), gamete quality (variations in fertilisation rates and embryo survival), and also sexual behaviour. Among species of interest for animal production, fishes and birds are generally considered as more directly sensitive to external factors (mainly temperature in fish, photoperiod in birds). In all species, it is therefore advisable that artificial photoperiodic treatments consisting of extra-light during natural short days (in chickens, turkeys, guinea fowl, sheep and goats) or melatonin during long days (in goats, sheep) be extensively used to either adjust the breeding season to animal producer needs and/or to completely overcome seasonal variations of sperm production in artificial insemination centres (mammals) and breeder flock operations (poultry, fish farming). Pure light treatments (without melatonin), especially when applied in open barns, could be considered as non invasive ones which fully respect animal welfare.Keywords: birds, fish, mammals, photoperiod, reproduction, seasonality Seasonal variations in marketed products of animal originSeasonal availability of animal products for human consumption has been common long before domestication. In farm animals this pattern has led to the development of breeding stocks aimed at providing animal products all the year round. Despite the fact that domestication processes, which reduce the dependency of farm animals on natural conditions, generally reduce seasonality of reproduction compared with their wild counterparts, a majority of animal-derived products remain accessible only seasonally. This is a consequence of the cycles of reproduction and production which are themselves seasonal as domestic stock have inherited the characteristics of the natural populations from which they originate (see below and Ortavant et al. (198...

Seasonal Variations in Clock‐Gene Expression in Atlantic Salmon (Salmo salar)

“…Such findings will ultimately be of great scientific interest as well as vast commercial importance in fish (Bhattacharya et al, 2007;Chemineau et al, 2007;Meseguer et al, 2008 ). Per3, 1a, and 1b as outliers.…”

Effects in genetic evaluation for semen traits in Czech Large White and Czech Landrace boars

“…Seasonal effects on female and male reproductive traits occur in most farm animal species (Trudeau and Sanford, 1990;Chemineau et al, 2007). In the temperate climate, seasonal effects may be explained mainly by the influence of the photoperiod and temperature whereas in the tropics also humidity may be of importance (Murase et al, 2007).…”

Stimulation of reproductive activity in anovulatory Alpine goats exposed to bucks treated only with artificially long days

“…Therefore, artificial photoperiod treatments could be used to modify the reproductive seasonality in males and females. Indeed, exposure of animals to 2 or 3 months of long -E-mail: joaldesa@yahoo.com days followed by either short days or a melatonin treatment, a hormone that mimics the effects of short days, stimulates their sexual activity during the non-breeding season (Donovan et al, 1994;Delgadillo et al, 2001;Chemineau et al, 2007). Another possibility to stimulate the sexual activity in anestrous females is the use of socio-sexual relationships.…”