Role of the vomeronasal organ in neonatal offspring recognition in sheep.

Twenty-five pregnant Dorsett ewes were randomly divided into three groups to test if ewes use their vomeronasal organs for offspring recognition during nursing. One group of eight ewes (procaine) were made anosmic by irrigation of the nasal olfactory apparatus with a zinc sulphate procaine solution. The second group of nine ewes (cauterized) had their vomeronasal organs rendered nonfunctional by cauterization of the nasoincisive duct. The third group of eight ewes were the controls. Parturition was synchronized in all ewes with betamethasone on Day 145 of gestation. Maternal responsiveness was tested two separate times with 1- to 2-day-old alien lambs. Each alien lamb trial was conducted 24 h apart. Cauterized ewes allowed alien lambs to suckle and they were unable to distinguish alien lambs from their own lambs, whereas the ewes in both groups with functional vomeronasal organs (procaine and control) violently rejected any alien lamb's attempt to suckle. Thus, female sheep use their vomeronasal organs for neonatal offspring recognition.

The brachial plexus in the chacma baboon (Papio ursinus).

The brachial plexus in each of ten embalmed, mature chacma baboons was dissected to document the structure and branching pattern of this nerve plexus in this increasingly used research animal. In general, the brachial plexus in the chacma baboon was similar to the plexuses in the vervet and other Old World monkeys. However, several aspects were comparable to those observed in domestic animals. Thus the bipedal and quadrupedal abilities of the chacma baboon were reflected in the structure of its brachial plexus.

A comparative study of the thickness of the tunica muscularis in the forestomach and abomasum of grey, white and black Karakul lambs.

Homozygous grey Karakul lambs are born with a lethal genetic factor responsible for death and weaning age. When put on a high roughage diet under field conditions they develop distended, thin-walled rumens and sand impacted abomasa. Homozygous white Karakul lambs have a similar factor but survive for a longer period. Black Karakul lambs are not affected. The present study was undertaken to compare by image analysis the thickness of the tunica muscularis of the forestomach and abomasum of 24-hour old grey, white and black Karakul lambs. One square centimetre samples were taken from equivalent areas in each case of the rumen, reticulum, omasum and abomasum of 38 embalmed Karakul lambs. Haematoxylin and eosin stained histological sections of each sample were studied with a Vids 2 Image Analyzer and the thickness of the circular and longitudinal muscle layers was measured. An analysis of variance indicated a significant difference between the groups in the thickness of the tunica muscularis of the rumen, reticulum and abomasum; the grey group displaying the thinnest and the black group the thickest. The omasa were not affected. The study indicates a reduction in thickness of the tunica muscularis of the homozygous grey and white lambs when compared to normal black lambs.

A comparative histological study of the number and size of the myenteric ganglia and neurones in the fore-stomach and abomasum of grey, white and black Karakul lambs.

Homozygous grey Karakul lambs are born with a lethal genetic factor responsible for death at weaning age. When put on a high roughage diet under field conditions they develop distended, thin-walled rumens and sand impacted abomasa. Homozygous white Karakul lambs have a similar factor but survive for a longer period. Black Karakul lambs are not affected. The present study was undertaken to compare by image analysis the number and size of the myenteric ganglia, and the number of myenteric neurones in the walls of the fore-stomach and abomasum of 24-h-old grey, white and black Karakul lambs. One square centimetre samples were taken from analogous areas of the rumen, reticulum, omasum and abomasum of 38 embalmed Karakul lambs. Haematoxylin and eosin stained histological sections of each sample were studied with a Vids 2 Image Analyzer. One way analysis of variance indicated a significant difference between the groups regarding the number and size of the myenteric ganglia and in the number of myenteric neurones in the reticulum, rumen and abomasum. The number and size of the ganglia and the number of neurones was greatest in the black lambs and decreased progressively in the white and grey lambs. The omasum was not affected. It is suggested that the paucity of myenteric ganglia and neurones in the regions examined is instrumental in causing the lethal condition described above.

The brachial plexus in the vervet monkey (Cercopithecus pygerythrus).

The brachial plexus in ten embalmed, mature vervet monkeys was dissected to document the structure and branching pattern of this nerve plexus in this frequently used research animal. In general, the brachial plexus in the vervet monkey was similar to the plexus of other Old World monkeys. However, several aspects were comparable to those observed in domestic animals. Thus the quadrupedal and bipedal abilities of the vervet monkey was reflected in the structure of its brachial plexus.

Angioarchitecture of the canine thyroid gland.

The extrinsic vasculature of the canine thyroid gland was compared to that of the human and it was considered possible that the dog does not possess a caudal thyroid artery, as often described in the literature. The thyroid capsule was relatively thin in the dog and its trabeculae appeared histologically to be continuous with the tunica adventitia of the blood vessels. The intrinsic vascular pattern simulated the lobular structure and the blood vessels were named according to their relationship, course, and major area of supply inside the gland. The veins and lymphatics were satellite to the arteries and were designated homonymously. The lymph capillaries were more closely associated to the follicular epithelium than were the blood capillaries.

Atypical thyroid follicles arising from an ultimobranchial-like cyst in a postnatal canine thyroid gland.

While investigating the intrinsic vasculature of the canine thyroid gland, atypical thyroid follicles were observed histologically, arising from a postnatal thyroid cyst of unknown origin, in stained sections of a male, 1-year-old, mesaticephalic dog. The animal was anesthetized, bled, killed by injection of Toxital directly into the heart, and perfused with 10% buffered neutral formalin solution. The thyroid tissue was fixed, embedded in paraffin, sectioned serially, and mounted on glass slides. Concordant with descriptions in the literature, this structure appeared to be a postnatal ultimobranchial-like cyst with direct connections to both ultimobranchial and mixed follicles. Seemingly, this observation has never been reported previously in the canine and would lend support to the hypothesis that ultimobranchial-like cysts may give rise to these atypical follicles. However, the authors are not totally convinced that all such thyroid cysts are solely ultimobranchial in orgin. A review of the literature supporting this contention is discussed.

Is there a caudal thyroid artery in the dog (Canis familiaris)?

Attempts have been made to establish extent of similarities as well as dissimilarities between the canine caudal thyroid and human inferior thyroid artery. On the basis of origin, course, relationship, branching pattern, major area of supply, level of anastomosis, occurrence, etc., it is proposed to rename the caudal thyroid of the dog as the tracheoesophageal artery.