A.N. Bruere

The significance of the XO syndrome in infertility of the mare

Abstract Analysis of mitotic chromosomes revealed the consistent lack of one sex chromosome in each of the four tissues studied from an infertile mare. Centromere staining of the chromosomes and sex chromatin studies confirmed that this mare had the karyotype 63XO. Clinically this mare was small for her age and breed, exhibited intractable behaviour while at stud and was never observed in oestrus. Her genitalia appeared normal although the uterus and ovaries were small and macroscopic follicles were absent. Histologically, a number of presumptive atretic Graafian follicles and a discrete area of apparently functional luteal tissue were present in the right ovary. The significance of these findings is discussed and compared with the features of analogous syndromes associated with the XO anomaly in other species. It is suggested that the XO anomaly in the horse may not always be associated with complete sterility.

Preliminary observations on the occurrence of the equine XO syndrome.

Abstract Clinical and cytogenetic observations were made on seven mares which had never bred when sent to stud. In six of these, the chromosome count was 63,XO with one X chromosome missing and, in one case, two cell lines were present with a 63,XO/64,XX chromosome constitution. All mares showed signs of the equine Turners syndrome and it is suggested that sex chromosome abnormalities may be quite a common cause of sterility in the mare.

An inherited cataract in New Zealand Romney sheep.

A bilateral cataract was noted to occur in sheep on a New Zealand Romney stud. Extensive breeding trials showed that this defect was inherited as an autosomal dominant. As such this form of cataract is of minimal importance to the sheep industry as control is merely by culling affected individuals.

XY gonadal dysgenesis in a Charolais heifer

Abstract The anatomical and cytogenetical findings on a three quarter Charolais heifer which failed to show oestrus are described. The heifer had a karyotype of 60, XY in all tissues studied and was sex chromatin negative. The vulva and vagina were normal, the cervix had a double external os, the left ovary was partially hypoplastic, there was no right gonad and a cystic dilatation of the fallopian tube was recorded.

XX/XY mosaicism in lymphocyte cultures from a pig with freemartin characteristics

Abstract Extract The freemartin condition as a cause of intersexuality in the adult pig has been suggested but never demonstrated. Hughes (1929) and Benoit (1964), both described cases of placental anastomosis between opposite sexed piglets with the formation of a freemartin-like condition in one of the foetuses. It is surprising, however, from the numerous studies over an anatomically wide range of adult pig intersexes, that none of these has shown characteristics consistent with freemartinism as described in other species. Bovine and ovine freemartins show varying degrees of intersexuality from near male in some cases to near female in others (Lillie, 1917; Bruere and McNab, 1967). In both the bovine and ovine freemartin cases cited, certain anatomical and histological features are apparently constant. These include a blind urogenital sinus, absence of a formed scrotum even in the presence of descended gonads, and characteristic sex cord formation without spermatogenic elements (Lillie, 1917). The certa...

A syndrome of dental abnormalities of sheep: I. Clinical aspects on a commercial sheep farm in the Wairarapa.

Abstract A syndrome of dental abnormalities in sheep is described. The features of the syndrome include excessive wear of deciduous incisor teeth, maleruption of permanent incisors associated with an osteopathy of mandibular bone, and the frequent formation of dentigerous cysts. Periodontitis of incisor teeth was present in some cases, and excessive incisor wear and premature tooth-loss were recorded in most sheep over 3 years old. The syndrome has been recorded on a number of farms in the lower part of the North Island, but was probably exacerbated in the Wairarapa district by inclement weather during 1977 and 1978. Excessive wear of the incisor teeth of cattle was also recorded on the same farms that had the problem in sheep. The presence of low copper levels, determined by liver and blood analyses from affected animals, is discussed in relationship to the complex, and possibly nutritional, aetiology.

Genital infection of ram hoggets associated with a gram-negative pleomorphic organism

Abstract Extract An acute epididymitis affecting mainly young rams and associated with a gram-negative pleomorphic organism was first reported in New Zealand in 1955 (1). Subsequently a similar syndrome attributed to Actinobacillus seminis has been reported in Border Leicester and other rams in Australia (2) (3) (4). A like condition also described in Australia in a single crossbred ram was causally attributed to Histophilus ovis (5). Actinobacillus seminis was isolated from an epididymal infection in a Rambouillet ram in America (6) and from a Dorper ram in South Africa(7).

A syndrome of dental abnormalities of sheep: II. The pathology and radiology

Abstract Histological and radiographic examination of 23 ewe heads has revealed that mandibular osteopathy is a feature of the ovine dental abnormality syndrome described by Bruere et al.(3) The bone changes consisted of excessive irregular remodelling of bone with osteoporosis. Developmental faults were also demon-strated. The most dramatic of these were dentigerous cysts involving unerupted permanent incisors, although malposition-ing of permanent incisors was also observed. A histological feature of the excessive incisor wear was chronic pulpitis, perhaps a. result of the rate of wear exceeding the rate at which protective secondary dentine could be de-posited in the pulp cavity. A number of nutritional deficiencies is known to cause gener-alised osteoporosis. Recognition of the osteopathy described here thus supports the clinical evidence of Bruere et al.(3) that a nutritional disorder could be a major factor in the pathogenesis of this syndrome.

Accreditation for freedom from ovine brucellosis.

Abstract The results of operating a voluntary ovine brucellosis accreditation programme in 14 stud and 9 commercial flocks in the Manawatu district is reported. From a total of 1992 CF test results there were 47 positive and 14 suspicious reactions; a total of 61 reactions (3.06%). Fifty six of these occurred in rams vaccinated during the previous 12 months, and only one further ram with epididymitis had a suspicious, and then a positive, CF test and is assumed to have had brucellosis (0.05%). One of the remaining three suspicious reactions was confirmed as a false suspicious, and the other two remain unclassified as either true or false. It was concluded the CF test is both highly sensitive and specific, and that the official acceptance of accreditation schemes is an urgent priority for the sheep industry.

Epiphysitis in rams following vaccination against Brucella ovis infection.

Abstract Lameness following the combined use of Brucella abortus strain 19 and Br. ovis vaccine for the prevention of Br. ovis infection was recorded in 40 of 300, 10 to 11-months-old Perendale rams. Epiphysitis caused by Br. abortus strain 19 was confirmed in selected cases and radiological examination of affected limbs was found to be of value in clinical diagnosis. It is emphasised that the control of ovine brucellosis in stud flocks should first be based on the clinical examination of genitalia and the Br. ovis complement fixation test.