In this paper, we present the results of five years of experimentation on playing at altitude. Since 1940, when the lethal action of dilutor of tartrates on spermatozoa demonstrated to date, we have advanced in the study of reproduction, but since this topic so broad and so much interest for its practical implementation, we believe our results should be considered as a preliminary survey in this study. Each point must be reviewed and analyzed carefully, because of the results obtained in experimental work depends establishing scientific guidelines for the reproduction and development of animal population of our mountain.

The author studies the semen of the rams in its known characteristics, and states the differences found at 4500 mts. of altitude. The very well know fact of reduced birth rate (50 to 60 % versus 100 % at sea level), is due to several factors : The deviations of pH are greater than at sea level. The number of spermatozoids is rather high, but there are young forms frequently seen, with a decrease of their mobility, as well as the presence of white blood cells, epithelial cells, etc. In fact he founds only 26 % of 58 supposedly normal rams, which could be considered suited for reproduction. By means of artificial insemination, and using selected males, he obtained 86,4 % of fertility, the result being very impressive as the ewes served were those so called "machorras" (infertiles). This paper proves, therefore, that the reduced birth rate of sheep at high altitude, is due to a diminishing ...

Hasta el año de 1940, la opinión predominante respecto de la disminución de la natalidad del ganado ovino en el altiplano comparada con la que se obtiene a nivel del mar, se basaba en la creencia de la existencia de ovejas "machorras" incapaces de reproducirse. A pesar de esto, los ganaderos empleaban 5 o 7 machos por 100 ovejas aclimatadas, de larga residencia, con sangre procedente de los carneros traidos durante la Colonia; mientras que, a nivel del mar, nunca excedió este porcentaje de 2 o 3. Con todo era extraordinariamente difícil obtener, con animales importados, un coeficiente de reproducción superior a 30% o 40%, particularmente el primer año de aclimatación, durante el cual el procentaje de fertilidad caía a menos de 20% con el consiguiente perjuicio económico.