The role of Haemophilus somnus in bovine early embryonic death. III. The effect of the organism on embryos by day 21 postbreeding.

A study using 11 healthy, mature Holstein-Friesian heifers was designed to determine whether 1) H. somnus induces gross and/or histopathological changes of the uterine tract and embryos, 2) H. somnus has a short and/or long-term effect on the ovarian activity, 3) prior exposure to H.

The use of embryo collection techniques in Holstein heifers: A model to study early embryonic death.

Twenty-three cyclic Holstein heifers were purchased for use as embryo donors to study the effect of intrauterine exposure to Haemophilus somnus on the number, quality, and viability of embryos produced. Few problems were encountered using standard superovulation and nonsurgical embryo collection techniques on virgin heifers. Based on three or more ovulations, as determined by palpation per rectum of the ovaries at the time of embryo recovery, 28 of 30 heifers responded to the superovulation regimen.

The role of Haemophilus somnus in early embryonic death. I. The effect of the organism on embryos by day 8 postbreeding.

A study using 23 healthy, mature, virgin Holstein-Friesian heifers was designed to determine if H. somnus caused detrimental effects in early bovine embryos and the mechanism(s) that induced these effects. Superovulated heifers were artificially inseminated 12 and 24 h after standing estrus using highquality, Haemophilus-free semen from a single ejaculate of one bull.