oriLirmx of rnEnNANcv. 149 



Mare. 



The usual period of gestation with the Mare is eleven inonths, though 

 it may vary between ten and twelve. 



From the observations of Winter, Brugnone, Tessier, and Grille, made 

 on 2S4 Mares, it results that the shortest period of gestation was 307 

 days, and the longest 394 days — or a mean duration of 34() days. 



(iayot, in 25 instances noted at the Haras of Pin, France, found the 

 average to be 343i days ; the shortest being 324 days, and the longest 

 3G7 days. 



A writer in the Journal d'Econoutie riiralc hclge for 1829. cited by 

 Rainard, gives as the minimum 322 days, maximum 41!) days, the 

 average being 347 days. 



Colin gives the average as 345 days, though birth may occur at 

 330th to 365th, and sometimes to the 380th day. 



Dieterichs gives the shortest period as 307 to 317 days, and the 

 longest as 409 to 419 days— the average being 330 to 342 days. Bau- 

 meister and Rueff give a minimum of 330 days, or eleven months, the 

 maximum as 420 days, or fourteen months' — the average as 340 days, or 

 \\\ months. 



A correspondent of the Field (May 2(jth, 1894) alludes to a Mare 

 which foaled twelve months and tvveuty-tive days after the last 

 senice. 



With regard to the influence of breed on tlie duration of pregnancy, 

 we have the researches of Baumeister and Rueff ; from these it appears 

 that, witli pure-bred Persian mares, the gestation period was 341 days — 

 343 for male foals, and 338 for females ; in thoroughbred Arab Mares, the 

 average was 338 days — 339 for males and 337 for females ; in high- 

 bred Russian Mares, some of which belonged to the Orloff race, the 

 average duration was 341i days — 341 for males and 342 for females. 

 With Hnglish Mares, the'y found that in half-breds the average was 

 339^ days — 340 for males, and 339 for females. 



Saint-Cyr, referring more particularly to Gayot's observations, ax-rives 

 at the following conclusions : 



1. In the Mare, the normal duration of pregnancy may be fixed 

 between 340 to 350 days— this being tlie interval in wliich the majority 

 of Foals are born. 



2. Some Foals may be born alive from the 300th to tlie 310th day, 

 but this is rare. 



' Hanion [H^cueil <I> Mt<l. VeUrinaln, lSt57) iilludes to thf ca«e of a Mare seven 

 yeara old, which went beyond her ordinary jwriod of pre^jnancy, only nianifeHtini; at the 

 usual time the customary signs of foalinij; though the.ie noon ctBHed, but recurred ajjain 

 in fifteen days, only to disappear in a short time. .\ft«?r this interval tlie animal 

 appeared t<i l»e quite well, feeding and working as Ixfore. At the sevcntt i-nth month 

 of pregnancy she was in the same condition : but on the fifteenth day of the eighteenth 

 month, she was sei/.ed with serious .■•ymptonis which continued during four days, when 

 death ensued. Hamon txaniined the body in th<- presence of many {)eople, who were 

 much interested in the case-, and discovered a Foal which weighed seventyhve kilogrammes, 

 and was as fat and fresh-looking as if it had been extracted at the normal jK-riod. The 

 tongue protruded from the mouth, the eyes were almost gone, the mu?<cles were well 

 developed but somewhat blo<xlle»s, and the position of the fnt\is was natural. The 

 lunbilical cord had the same asjn-ct as in ordinary ca-ses, but there was no bl<K>d in its 

 vt-isels, and it waa ruptured at five or six centimetres from the alxlominal walls. The 

 futal envelopes were hyi>ertr<>phied. their tot.il thickness being four to fiv.- centimetres ; 

 otherwise they were healthy. The rerrix uteri was of a great thickness and very rigid ; 

 when dilated it would only allow the passage of the fist. The litpior amnii wa« reddish 

 coloured. 



