Samples for microbiological culture were collected from the uterus of bitches using transcervical uterine cannulation (31 samples, 23 bitches) and from the uterus, cervix and vagina post mortem (19 bitches) at all stages of the reproductive cycle. Samples were cultured for aerobic and anaerobic bacteria and for aerobic mycoplasmas. Bacteria were always found in the uterus during pro-oestrus and oestrus (12 positive in 12 cultures) and rarely at other stages of the reproductive cycle: during anoestrus (one in 14) and other stages (none in 24). When microorganisms were detected at three sites post mortem, those found in the cervix and vagina were always of the same species as those found in the uterus. In six out of 13 instances, microorganisms were found in the cervix or vagina when none were found in the uterus. The mean number of isolates, number of bacteria seen in uterine cytology and bacterial growth were greater (P < 0.005) during oestrus and pro-oestrus than at other stages. Bacteria isolated from the uterus, in order of frequency, were Escherichia coli, Haemophilus species, alpha-haemolytic streptococci, Corynebacterium species, Streptococcus canis, Alcaligenes faecalis, Bacteroides species, Pasteurella species and Proteus mirabilis. No mycoplasmas were cultured from the samples. This study indicates that the uterus of the normal bitch has a uterine microflora during pro-oestrus and oestrus that is similar to that of the vagina and cervix.

The use of vaginal cytology and plasma progesterone determinations in the management of 11 bitches presented to our small animal fertility clinic are described. Nine bitches were mated or artificially inseminated and seven became pregnant. Reproductive patterns detected included failure of ovulation, prolonged pro‐oestrus with late ovulation, short pro‐oestrus/oestrus with early ovulation, short pro‐oestrus/oestrus with late ovulation and normal pro‐oestrus/oestrus with late ovulation.

Corpora lutea (CL) from naturally cycling Corriedale ewes were obtained in the mid- and late luteal phases of the oestrous cycle (Days 9 and 13; 5 ewes per group). The cellular composition of these CL was compared by ultrastructural morphometry to determine whether there were changes in numbers of large and small luteal cells consistent with differentiation of some small luteal cells to large luteal cells during the last part of the luteal phase. No differences between Days 9 and 13 were detected in luteal volume, plasma progesterone concentration, or volume density of any component of the luteal tissue. Large luteal cell numbers (mean +/- s.e.m.) were lower per unit volume of luteal tissue on Day 13 than on Day 9 (14.1 +/- 0.5 vs 18.4 +/- 1.3 X 10(3)/mm3, P less than 0.05). Mean volume of the individual large luteal cells was greater on Day 13 than on Day 9 (19.65 +/- 0.72 vs' 15.60 +/- 1.34 micrograms 3 X 10(3), P less than 0.05). However, there were no significant differences in numbers or volumes of small luteal cells between Days 9 and 13, and total numbers of large luteal cells per CL were not different between these two days. These results provide no support for the hypothesis that small luteal cells differentiate into large luteal cells during the oestrous cycle of the sheep.

Samples for endometrial cytology were collected both from live bitches using transcervical uterine cannulation (n = 48) and postmortem (n = 10). The cells identified were endometrial epithelial cells, leucocytes, erythrocytes, spermatozoa, bacteria and cervical or vaginal cells. The endometrial epithelial cells varied morphologically throughout the reproductive cycle and had signs of degeneration during late dioestrus and during early and mid-anoestrus following dioestrus and postpartum. Neutrophils were the most common leucocytes observed during pro-oestrus, oestrus, dioestrus and early pregnancy, and lymphocytes during anoestrus. Macrophages were frequently seen during anoestrus. Erythrocytes were found in variable numbers at all stages of the reproductive cycle. Spermatozoa were detected in samples collected during oestrus and early pregnancy in bitches which had their last mating one to three days previously. Bacteria were commonly observed during pro-oestrus and oestrus. Cornified cervical or vaginal cells were present during pro-oestrus and oestrus. This study demonstrated that the numbers, types, proportions and morphology of cells in endometrial cytological samples from normal bitches varied throughout the reproductive cycle.

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