A critical period in the development of the horse / by J. C. Ewart

Abstract

At a meeting 1 of the Central Veterinary Medical Society of London, at which I exhibited a number of young horse embryos, I had barely time to allude to what may prove a subject of some practical importance, viz., the apparatus provided for nourishing the embryos during the early weeks of development. This apparatus (which consists mainly of what are known as the foetal appendages) I was led to consider from a breeder's point of view by Lord Arthur Cecil asking me, about a year ago, if I could account for so many mares breaking service from the sixth to the ninth week. At the time I could only answer that I agreed with his lordship in believing it was in many cases due to the detachment and escape of an embryo. I have frequently found mares all right, as far as I could judge, at the end of the sixth week, and all wrong some weeks later. This seems to be not an uncommon experience, more especially at the beginning of the breeding season, hence it is always urged by experts that mares should be " tried " frequently during at least the first two months. If holding at the end of the ninth week no further trouble is, as a rule, anticipated. But no one has, as far as I am aware, explained why the breeder experiences so many difficulties during the earlier weeks. According to the evidence obtained by the Royal Commission on Horse Breeding, it appears that about 40 per cent, of the mares selected for breeding fail to produce offspring during any given year. This is a very high percentage 1-1th March (see the Field, 13th March 1897). b A CRITICAL PERIOD IN THE of failure, but from reports recently received it seems to be still higher in certain districts in India. 1 Believing that some of my mares have proved unfruitful for the time being because of their frequently breaking service, and believing further that not a few of the disappointments that fall to the lot of breeders result from the same cause, I decided to examine material collected for another purpose, with a view to shedding fresh light on this difficult but important practical question. To admit of the conditions which obtain in the brood mare being more easily understood, I shall at the outset refer to the apparatus provided for the nourishment of the chick, and to the corresponding structures in one of the simpler mammals. The Chick's Foetal Appendages. 2 Every one who has examined a hen's egg at, say, the end of the ninth day of incubation, knows that the already well-formed chick is, as it were, mounted on a large, well-filled forage bag the yolk sac-from which it hour by hour draws its nourishment. But in addition to the familiar yolk sac there is a second sac, in its way quite as important, though empty of food, viz., the thin compressed sac lying in contact with the shell, which plays the part of a breathing organ or lung. This second sac is known as the allantois.

V - Studies of the epidermal structures of birds

“…As already noticed, the neossoptile coat exists in members of Anseriformes, Galliformes, and Passeriformes, but while Ewart (1921) has figured three definite coats in the first of these groups, it has so far been impossible to find them all in the others.…”

“…No trace of the mesoptiles found in the ninth pair of rectrices of the Mallard duck (Ewart 1921) have so far been found in the Khaki Campbell duckling.…”

“…It will be as Well at the outset to ensure a correct interpretation of terms used in this work, by reference to the table compiled by Ewart (1921), showing the sequence of feathers in a hypothetical Avian type from embryo to adult. Prefiloplumae, preplumulae and prepennae are typical constituents of nestling down, and will therefore be collectively spoken of as ; and instead of restricting the term Teleoptiles to Pennaceous Pennae as in the above table, it will be used for all types of adult feathers, as originally used by Gadow (1907), Pycraft (1907) and Newton (1896).…”

Ventral Hernia Repairs: 10-Year Single-Institution Review at Thomas Jefferson University Hospital

“…5 Recurrent ventral hernias after open suture repair can occur with a reported frequency of 31-49%. 6 The adjunctive use of a prosthetic material to the repair appears to attenuate this rate to 0-10%. 6 Despite the great morbidity associated with incisional hernia, no consensus exists on the best means for treatment.…”

“…6 The adjunctive use of a prosthetic material to the repair appears to attenuate this rate to 0-10%. 6 Despite the great morbidity associated with incisional hernia, no consensus exists on the best means for treatment. 5 Ramirez and colleagues 1 first described the use of a bilateral, innervated rectus abdominus-internal oblique muscle flap that is transposed medially to repair the central abdominal wall.…”