DEVELOPMENT OF THE HORSE. 23 



of temperature, of food, of companions, changes of his surroundings 

 or environment generally, will greatly influence mares, more 

 especially at the breeding season. 



It is well known that changes influence more or less markedly 

 all kinds of animals. A change from one country or one district 

 to another may, e.g., lead to increased fertility, or it may result in 

 complete sterility. This is doubtless because the reproductive 

 system is extremely sensitive to changes of every kind. In 

 several cases mares which I received from a distance required 

 several months to adapt themselves to their new conditions, and in 

 all cases the reproductive system was the last to assume its 

 normal state. But what bearing has this on the subject in hand ? 

 It all points to a very careful and thoughtful treatment of mares 

 at the beginning of the breeding season. For example, now 

 (April) that the grass is coming on, I might have several 

 mares mated with my zebra — mares which have been under 

 cover and generously fed during the winter, — and then turned 

 out to grass in the same field. The change from the loose- 

 boxes to the field would be nearly as great as from the South 

 of England to the Pentlands, and if the reproductive system 

 is most sensitive to changes, the chances would be strongly 

 against their settling. But even if proof against the effects of 

 substituting an outdoor for an indoor life, turning them one by 

 one immediately after mating would be most unwise. Some 

 mares, even when in foal, " tease " other mares as persistently as a 

 horse! In this way, the excitability which should be allayed, or 

 at least allowed to subside, might be kept up if not exaggerated. 

 At the beginning of the breeding season changes of food, of tem- 

 perature, and of the surroundings generally should be made as 

 carefully and judiciously as possible ; and during at least the first 

 two months after service the mares should neither be over- 

 excited nor over-exerted, neither chilled nor over-heated, neither 

 over nor under -fed, and, in fact, all extremes should be carefully 

 avoided ; and it should be remembered that drugs readily reach, 

 and may profoundly influence, even young embryos. 



If in this case being forewarned is to be forearmed, some 

 good may result from the conditions under which the horse 

 embryo exists during the early weeks of development having 

 been shortly explained. The practical application of the facts 



