Results of inseminations of cows in spontaneous and induced oestrus

Cow fertility depends on many factors, the most important of which are diet, maintenance, upkeep conditions, and technical-technological conditions of production in cattle breeding. If we accept this as correct, and it is, then the question appears, under the same conditions of diet, upkeep, and the technological production process, why some cows conceive and yield a calf each year, while others remain barren, even though the level of milk production per cow is approximately the same. An answer to this question would help resolve the problem of cow sterility. The paper shows the results of insemination of cows in spontaneous or induced oestrus following the administration of one or two injections of prostaglandin. Conception results in spontaneous oestrus following the first insemination were 43.4%(33/76), after the second 23.7%(18/76), after the third 11.8% (9/76), and after the fourth and all subsequent 21.1% (16/76) with an insemination index of 2.3. The results of conception in cows in induced oestrus following a single administration of prostaglandin after the first insemination were 68.4% (13/19), the second and third 15.8% (3/19) each, with an insemination index of 1.5. Following two injections of prostaglandin in induced oestrus, the conception results after the first insemination were 100 % (5/5) with an insemiantion index of 1.0.