Rate of discharge and morphology of sweat glands in the perineal, lumbodorsal and scrotal skin of cattle.

The rates of evaporation of moisture from the skin in the lumbodorsal, perineal and scrotal regions of cattle were measured in thermoneutral and high environmental temperatures. The rates of evaporation from the perineal and scrotal regions of heifers and bulls were significantly (P < 0.001) greater than those from the lumbodorsal areas. The lumbodorsal rate of evaporation increased significantly (P < 0.001) when cows and bulls were transferred from a thermoneutral to a hot environment and the rate of evaporation from the scrotum of bulls showed a similar increase; the rate of evaporation from the perineum of cows increased to a smaller extent (P < 0.05) under the same conditions. The rate of evaporation from the perineum of cows reached a maximum on the day of oestrus but the stage of the oestrous cycle had no effect on the lumbodorsal rate of evaporation.

A quantitative morphological study of the bovine vaginal epithelium during the oestrous cycle.

Samples were collected post mortem from 28 cycling parous cows. At all stages of the oestrous cycle, the cranial vaginal epithelium was thinner (P less than 0.001), had fewer cell layers (P less than 0.001) and proportionally more superficial columnar cells (P less than 0.001) than more caudal regions. At all stages of the cycle there were more intraepithelial lymphocytes caudally than in more cranial regions (P less than 0.001). At oestrus the proportion of superficial columnar cells was maximal, having increased from the late dioestrus proportions of 1, 29 and 40 per cent of all superficial cells to 15, 54 and 83 per cent in caudal, middle and cranial regions, respectively (P less than 0.02). However, the epithelial thickness in all regions of the vagina was greatest at metoestrus (P less than 0.02). At this stage, the number of cell layers was greater than at any other stage (P less than 0.05).

A pheromonal function for the perineal skin glands in the cow.

Two cows with synchronised oestrous cycles were housed with a Friesian bull. During the midcycle period of the cows, one cow was given an intradermal injection of adrenaline in the perineal region. This caused local sweat gland discharge. The other cow was treated with water. The number and types of bull-to-cow behaviours were recorded before, during and after the day of treatment. This was repeated at three-weekly intervals for a total of four times. On the day of treatment the bull directed a greater proportion of olfactory behaviours towards the adrenaline-treated cow than the other cow (P less than 0.05). There was no difference between the cows before or after the day of treatment. The above experiments were repeated with a Hereford bull who showed the same response as the Friesian for the first two but not the last two experiments. The increased proportion of bull olfactory behaviours elicited by an increased perineal skin gland discharge, adds support to our hypothesis that the perineal skin glands are the source of an oestrous pheromone in the cow.

Sweat glands of the scrotum of the bull.

Skin samples were taken post mortem from the scrotum, abdomen and neck of 4 mature bulls. The volume of sweat glands per unit skin surface area of the scrotum was greater than that of other body regions. Within the scrotum there was a gradient in sweat gland volume increasing from proximal through to distal parts of the scrotum. These results suggest a previously unidentified variable cooling capacity of the scrotum depending on testicular descent.

Histochemistry of mucins of pig intestinal secretory epithelial cells before and after weaning.

Two histochemical staining techniques, Alcian blue/PAS and high-iron-diamine/Alcian blue, which differentiated neutral from sulphated and sialylated acid mucins were applied to sections of duodenum, ileum, caecum, colon and rectum from pigs aged one day, 3 weeks and 10 weeks. In each age group, sulphated-acid mucins predominated at all sites, particularly in the large intestine. In both the small and the large intestine, non-sulphated mucins occurred mainly at the bases of the crypts. Neutral mucins occurred in a few goblet cells in crypts and villi, either alone or together with acid mucins; neutral mucins increased away from the bases of the crypts. No changes were noted in the caecum, colon or rectum of pigs one, two, 5 or 13 days after weaning onto a diet containing soya protein. In the small intestine, there was a transient increase in the numbers of goblet cells in the crypts and villi, a relative increase in sulphated and a decrease in non-sulphated acid mucins and a change in the distribution of sulphated mucins in the crypts. No change in proportions of neutral and acid mucins was detected.

A quantitative morphological examination of bovine vulval skin glands.

In adult cows the volumes of sweat and sebaceous glands per unit skin surface area (ssa) in the vulva were greater (P less than 0.01) than in the neck, lip or eyelids. Within this perineal region skin gland volumes were greater dorsally than ventrally (P less than 0.01). Adult cows had much greater (P less than 0.01) volumes of perineal skin glands per unit ssa than 8 weeks or 6 weeks old heifer calves or steers. There was little or no difference between animal categories in neck skin gland dimensions. Adult morphology of perineal sebaceous glands was present in 15 and 18 months but not 6 and 9 months old heifer calves. The skin glands of the perineal region in cows should be considered as specialised skin glands.

Effect of oestradiol-17 beta on perineal and neck skin glands in heifer calves.

Ten 16-week-old Friesian x Hereford heifer calves were split into experimental and control groups. Experimental animals were given an implant of oestradiol-17 beta in the ear whilst controls were given blank implants. They were killed 14 days later. After implantation the experimental group had consistently greater (P less than 0.01) plasma concentrations of oestradiol-17 beta than the control group. After death, sebaceous gland volume in the perineal region was greater (P less than 0.01) in the experimental than in the control group, whereas sebaceous gland volume in the neck was smaller (P less than 0.01). Sweat gland volume in the perineal region was greater (P less than 0.01) in the experimental than in the control group. There was no difference between groups in the volume of sweat glands in the neck.

Amount and distribution of vestibular-associated lymphoid tissue in calves and adult cows.

Normal reproductive tracts were obtained from 11 adult cows, five eight-week-old and five six-week-old heifer calves. Lymphoid nodules and aggregations (loci) were localised in vestibules by immersion in 2 per cent acetic acid. Adults had significantly more loci (P less than 0.001) than eight- or six-week-old calves, there being means of 194.6, 44.2 and 7.4 loci per vestibule, respectively. In all age groups there was a greater concentration (number cm-2) of loci along the median ventral groove than the side walls (P less than 0.001), and in the caudal third of the vestibule than in the middle or cranial thirds (P less than 0.001). The concentrations of loci were the same in adults and eight-week-old calves but significantly lower in six-week-old calves (P less than 0.01).