This paper reviews the equine granulosa cell tumour (GCT) and describes the clinicopathological features, treatment and outcome in seven cases of GCT in mares. Mares were presented with unilateral ovarian enlargement during the 2007 to 2010 breeding seasons. The mean (sd) age of the mares was 11.7 (5.96) years. Three mares were multiparous barren, three were nulliparous and one was primigravida. Behaviour at presentation was 57 per cent anoestrus, 28 per cent with stallion-like behaviour and 14 per cent with persistent oestrus. All mares had unilateral ovarian enlargement. Six non-pregnant mares had a small and inactive contralateral ovary; the pregnant mare had a single small corpus luteum on the contralateral ovary and was at three-and-a-half months' gestation. Enlarged ovaries measured 7 cm to an estimated 30 cm in diameter. 28 per cent had a multicystic ultrasound appearance, 57 per cent were dense structures and 14 per cent were of mixed appearance. Mean concentrations of progesterone were <1 ng/ml, oestrone sulphate 3.06 (2.32) ng/ml and testosterone 0.58 (0.64) nmol/l in non-pregnant mares. Inhibin was elevated in all non-pregnant cases at 7.6 (12.45) ng/ml. The pregnant mare had concentrations of progesterone 2.5 ng/ml, oestrone sulphate 81.0 ng/ml, testosterone 1.9 nmol/l and inhibin 1.31 ng/ml. Mares demonstrating stallion-like behaviour had a significantly higher (P<0.001) testosterone concentration (1.85 [0.07] nmol/l) than those that did not (0.34 [0.26] nmol/l). Three mares underwent unilateral ovariectomy and resumed cyclic ovarian activity within nine months of surgery.

The first 8 weeks of pregnancy is a critical time, with the majority of pregnancy losses occurring during this period. Abnormal chromosome number (aneuploidy) is a common finding in human miscarriage, yet is rarely reported in domestic animals. equine early pregnancy loss (epL) has no diagnosis in over 80% of cases. The aim of this study was to characterise aneuploidies associated with equine EPL. Genomic DNA from clinical cases of spontaneous miscarriage (EPLs; 14-65 days of gestation) and healthy control placentae (various gestational ages) were assessed using a high density genotyping array. Aneuploidy was detected in 12/55 EPLs (21.8%), and 0/15 healthy control placentae. Whole genome sequencing (30X) and digital droplet PCR (ddPCR) validated results. The majority of these aneuploidies have never been reported in live born equines, supporting their embryonic/fetal lethality. Aneuploidies were detected in both placental and fetal compartments. Rodents are currently used to study how maternal ageing impacts aneuploidy risk, however the differences in reproductive biology is a limitation of this model. We present the first evidence of aneuploidy in naturally occurring equine EPLs at a similar rate to human miscarriage. We therefore suggest the horse as an alternative to rodent models to study mechanisms resulting in aneuploid pregnancies.

This paper reviews the equine granulosa cell tumour (GCT) and describes the clinicopathological features, treatment and outcome in seven cases of GCT in mares. Mares were presented with unilateral ovarian enlargement during the 2007 to 2010 breeding seasons. The mean (sd) age of the mares was 11.7 (5.96) years. Three mares were multiparous barren, three were nulliparous and one was primigravida. Behaviour at presentation was 57 per cent anoestrus, 28 per cent with stallion-like behaviour and 14 per cent with persistent oestrus. All mares had unilateral ovarian enlargement. Six non-pregnant mares had a small and inactive contralateral ovary; the pregnant mare had a single small corpus luteum on the contralateral ovary and was at three-and-a-half months' gestation. Enlarged ovaries measured 7 cm to an estimated 30 cm in diameter. 28 per cent had a multicystic ultrasound appearance, 57 per cent were dense structures and 14 per cent were of mixed appearance. Mean concentrations of progesterone were <1 ng/ml, oestrone sulphate 3.06 (2.32) ng/ml and testosterone 0.58 (0.64) nmol/l in non-pregnant mares. Inhibin was elevated in all non-pregnant cases at 7.6 (12.45) ng/ml. The pregnant mare had concentrations of progesterone 2.5 ng/ml, oestrone sulphate 81.0 ng/ml, testosterone 1.9 nmol/l and inhibin 1.31 ng/ml. Mares demonstrating stallion-like behaviour had a significantly higher (P<0.001) testosterone concentration (1.85 [0.07] nmol/l) than those that did not (0.34 [0.26] nmol/l). Three mares underwent unilateral ovariectomy and resumed cyclic ovarian activity within nine months of surgery.

Summary This report describes the successful management of a pregnant 14‐year‐old seven‐eighths Thoroughbred mare with an ovarian granulosa cell tumour. The mare initially presented with unilateral ovarian enlargement whilst being managed for artificial insemination, demonstrating normal ovarian function with ovulation from the contralateral ovary leading to conception. The mare subsequently re‐presented with stallion‐like behaviour at 3.5 months gestation and ovarian suppression was evident. The mare maintained her pregnancy and delivered a live colt foal at term. Ovariectomy was performed 3 months post foaling and the mare regained cyclic activity 9 months post surgery. The mare then conceived and became pregnant once more. The diagnostic and therapeutic challenges during pregnancy are discussed.

Four levels of a proprietary concentrate (0, 100, 200 and 400 g/day) were offered to Welsh Mountain ewe lambs receiving hay or straw ad libitum for 14 weeks. The apparent digestibility of the energy and nitrogen in the various diets was determined in a concurrent digestibility trial. The voluntary intakes of the straw and hay dry matter when given alone were 242 and 451 g/day respectively (28-4 and 49-2 g/kg W 0 " 73 per day). Straw intake increased with an increase in concentrate feeding up to a level of 25 % concentrate in the total dry matter and then declined. Hay intake declined linearly with increasing concentrate level (3 g/day decline per unit increase in the percentage of concentrate). In each case the total intake of dry matter and digestible energy increased with an increase in concentrate level. There was a positive within-treatment relationship between initial live weight and voluntary intake, an additional 0-019 Meal ME/day being consumed per kg increase in live weight. Within treatment groups lambs consuming relatively more food also made relatively higher weight gains. Estimates based on published standards of the metabolizable energy intakes required to produce the live weight changes observed on each treatment were considerably higher than the intakes recorded in the trial. Recent experiments by Blaxter and Wilson (1963), Holmes, Jones, Drake-Brockman and White (1965) and Campling and Murdoch (1966) support the opposite conclusion, that the higher the quality of the roughage the greater the depression in intake when concentrates are given.