“Fatness” as a Cause of Sterility

Extract

The general experience of breeders, supported by statistical evidence in the case of sheep, has shown that a good thriving, but not over-fat, condition during the breeding season is that which is most conducive to a high fertility. It has been shown further that the practice of “flushing” or “springing” ewes (i.e. artificially stimulating them by means of an extra supply of special food) shortly before and during tupping time results in an increased number of births at the succeeding lambing time. On the other hand, an excessive quantity of nutriment producing a great deposit of fat is known to be prejudicial to the proper discharge of the reproductive functions. No better example could be given of the way in which overfeeding results in a condition of sterility than that of the barren shire mares which have been a noteworthy feature at many agricultural shows. It is a matter for regret that those animals, whose appearance justified them as prize-winners, should in many cases have proved valueless as brood mares owing to the methods of feeding to which they had been subjected in preparing them for show. The association of sterility with a too fattening diet is as common among cows, sheep and pigs as it is among mares. Thus Cornevin writes: “Chaque aunée, dans les concours, nous avons sous les yeux des spécimens des plus belles races ovines et porcines qui, véritable modèles de bonne confirmation, de puissance assimilatrice et d'aptitude á prendre la graisse, restent stérile.” Moreover, Mr Edward Brown, the honorary secretary of the National Poultry Organisation Society, ascribes the decrease in egg production by poultry during the winter months in part at least to overfeeding.