Search PubMed⌕ Search

Biomedical subjects

R A McFeely

Publications and source records attributed to R A McFeely.

At least 19 recordsLinked to original sources
PubMed1993

A 14/20 chromosome translocationp in Simmental cattle.

A 14/20 translocation was identified in 2 herds of Simmental cattle in the United States. All of the animals that carried the translocation had a common sire that was identified subsequently to carry the translocation. The semen of the bull had been used to inseminate a vast number of cows, so a substantial number of Simmental cattle in the United States may carry the 14/20 translocation. This translocation could have a detrimental effect on fertility in carrier animals; however, there are insufficient data about this particular abnormality to form conclusions. There appears to be sufficient evidence to urge caution in selecting carriers for breeding stock, especially when the potential exists for widespread dissemination of the abnormality through the use of artificial insemination.

Animals↗
PubMed1993

Chromosome abnormalities.

Chromosome abnormalities have been described in food animals since 1964. Some are self-limiting because they cause sterility or other developmental defects incompatible with normal growth and development, making them unacceptable for production systems. Others, however, cause no discernible phenotypic abnormalities but, in breeding animals, result in increased levels of embryonic mortality and reduced litter size. Although the extent of loss of reproductive efficiency is not entirely understood at this time, care must be exercised in recommending animals carrying a chromosome abnormality to be used as breeding stock. This is of particular concern if animals are to be used extensively in artificial insemination programs.

Animals↗
PubMed1990

Standard karyotype of the domestic horse (Equus caballus). Committee for standardized karyotype of Equus caballus. The Second International Conference for Standardization of Domestic Animal Karyotypes, INRA, Jouy-en Josas, France, 22nd-26th May 1989.

The following decisions concerning the banded karyotype of the horse (Equus caballus) were made at the second International conference for Standardization of Domestic Animal Karyotypes, held at Jouy-en Josas, France, 22nd-26th May 1989: (1) numbering of the chromosomes was modified to correspond to an arrangement into only two groups (the non-acrocentrics and the acrocentrics) within which the autosomes are placed according to length alone; (2) a more compact karyotype arrangement was adopted: chromosomes 1 to 5 on the first row, 6 to 10 on the second, 11 to 13, and, at the far right, X and Y on the third row, 14 to 19 on the fourth row, chromosomes 20 to 25 on the fifth, and 26 to 31 on the sixth row; (3) the NOR-bearing horse chromosomes were identified as numbers 1, 28 and 31.

Animals↗
PubMed1981

Induction of lymphosarcoma in sheep by bovine leukemia virus.

Newborn sheep inoculated with phytohemagglutinin (PHA)-treated short-term, cultures of lymphocytes from cattle infected with bovine leukemia virus (BLV) or with a BLV- infected long-term culture of bovine leukemic lymphocytes became persistently infected with BLV. Fifty percent or more of the sheep died with histologically confirmed lymphosarcomas. Cytogenetic studies of representative cases demonstrated that the tumors did not result from the progressive growth of neoplastic lymphocytes in the inoculum but rather from the neoplastic transformation of the recipients lymphoid cells. Neither BLV infection nor lymphosarcoma was observed in control uninoculated sheep or in sheep given injections of PHA-treated cultures of lymphocytes from BLV-free cows. The virus recovered from the tumorous sheep was indistinguishable from BLV morphologically, antigenically, and biologically, and its reverse transcriptase had the same cation preference and immunologic properties as the BLV enzyme. Persistent BLV infection and lymphosarcoma were also observed in a group of sheep inoculated neonatally with BLV-containing cell-free culture supernatants. These results extend previous observations on the high susceptibility of sheep to BLV infection and provide definitive evidence that BLV is a tumor-inducing virus.

Animals↗
PubMed1975

A review of cytogenetics in equine reproduction.

The karyotype of the horse consists of 64 chromosomes; 18 pairs have a terminal centromere and 13 pairs a non-terminal centromere. Identification of individual chromosomes is enhanced by the use of band-staining techniques which allow recognition of minor structural rearrangements of chromatin material. Seven previously reported cases of male pseudohermaphroditism with chromosome studies are reviewed. Three were genetic females, one was basically an XX/XY chimaera, one was an XX/XXY chimaera, and one was an XXXY. Also reviewed is an infertile mare with 63 chromosomes and no distinguishable sex chromosomes and a mare with juvenile genitalia and XO/XX sex chromosomes. It is postulated that, in the future, additional chromosome abnormalities will be found associated with maldevelopment of the equine reproductive system and as a cause of early embryonic death and abortion.

Animals↗