|Name:||Professor Claire Wathes
BSc PhD Dsc
|Post:||Professor of Veterinary Reproduction|
|Department:||Production and Population Health|
|Tel:||+44 (0)1707 666 000|
Farm Animal Health and Production Group
The Royal Veterinary College
Herts AL9 7TA
Claire is a member of the Reproduction Research Group. Her research is based on ruminant reproduction, most recently investingating metabolic effects on the reproductive tract environment.
Claire gained a first class degree in Zoology from the University of Birmingham followed, in 1978, by a PhD in dairy cow fertility at the University of Nottingham under the supervision of Professor Eric Lamming. Before joining the Royal Veterinary College in 1994, she worked for 10 years as a lecturer, then as a reader in the Department of Anatomy, University of Bristol; obtaining a DSc from Bristol in 1990. This was followed by 4 years in a research post at the Babraham Institute.
At the RVC Claire has served on a variety of committees including a long spell as Chairman of the Graduate School Committee. As Head of the Reproduction and Development Group for 12 years from 1995-2007 she was active in promoting research in this area, which was assessed as internationally competitive in the last two Research Assessment Exercises. She also established an elective in Reproduction for final year veterinary students. Externally she was Chairman of the BBSRC Steering Committee on ARK-Genomics from 2000-2008 and a member of the Horserace Betting Levy Board Veterinary Advisory Committee between 1997 and 2006. Professor Wathes is currently a director of Genesis Faraday. She was awarded the Research Medal of the Royal Agricultural Society of England (RASE) in 2006 with respect to her research on dairy cow fertility. She is now a member of the editorial advisory board of the journal of the RASE.
Claire supervises several PhD students. The Society for Endocrinology recently awarded a grant to one of her students, Andrew Clempson, to enable him to further his research in endocrine science/medicine through attending a two week course at their premises in Seattle.
Claire's main research interests are in the general area of ruminant reproduction. Her PhD work led to the development of milk progesterone profiles for monitoring fertility in dairy cows. Work at Bristol led to the discovery that oxytocin is an ovarian hormone in ruminants and was followed by investigations into the control of luteolysis, ovarian function and parturition, placental development and the causes of early embryo mortality. At the RVC her research into the underlying causes of poor fertility in cattle has continued.
Other current interests centre on the interactions between reproduction and nutrition in both cattle and sheep, work which has relevance to both farm animal and human fertility.
Funding currently comes from the Wellcome Trust, BBSRC, DEFRA and the Milk Development Council. This supports a dynamic group of research assistants and PhD students at the RVC who benefit from extensive collaborations with colleagues at other institutes in the UK and overseas.
BRICKELL,J.S., MCGOWAN, M.M., WATHES, D. C. (2010) Association between Neospora caninum seropositivity and perinatal mortality in dairy heifers at first calving. Vet Rec 167, 3. PubMed ID 20643884
WATHES, D. C., CHENG, Z., CHOWDHURY, W., FENWICK, M. A., FITZPATRICK, R., MORRIS, D. G., PATTON, J. & MURPHY, J. J. (2009) Negative energy balance alters global gene expression and immune responses in the uterus of postpartum dairy cows. Physiol Genomics 39, 1-13. PubMed ID 19567787
MORRIS, D. G., WATERS, S. M., MCCARTHY, S. D., PATTON, J., EARLEY, B., FITZPATRICK, R., MURPHY, J. J., DISKIN, M. G., KENNY, D. A., BRASS, A. & WATHES, D. C. (2009) Pleiotropic effects of negative energy balance in the postpartum dairy cow on splenic gene expression: repercussions for innate and adaptive immunity. Physiol Genomics 39, 28-37. PubMed ID 19567785
MAREI, W. F., WATHES, D. C. & FOULADI-NASHTA, A. A. (2009) The Effect of Linolenic Acid on Bovine Oocyte Maturation and Development. Biol Reprod. PubMed ID 19587335
BRICKELL, J. S., BOURNE, N., MCGOWAN, M. M. & WATHES, D. C. (2009) Effect of growth and development during the rearing period on the subsequent fertility of nulliparous Holstein-Friesian heifers. Theriogenology 72, 408-416. PubMed ID 19481791 PubMed ID 19059748
BRICKELL, J., MCGOWAN, M., PFEIFFER, D. and WATHES, D.C. (2009) Mortality in Holstein-Friesian calves and replacement heifers, in relation to body weight and IGF-I concentration, on 19 farms in England. Animal 3:8, pp 1175–1182.
BRICKELL, J., MCGOWAN, M. and WATHES, D.C. (2008) Effect of management factors and blood metabolites during the rearing period on growth in dairy heifers on UK farms. Domest Anim Endocrinol. In press.
WATHES, D.C. (2008) Metabolic effects on the reproductive tract environment and conception rates in the dairy cow. Havemeyer Foundation Monograph Series No 21, p15-19. In press.
BOURNE, N., WATHES, D.C., MCGOWAN, M. and LAVEN, R. (2008) A comparison between two routes of vitamin E supplementation on the vitamin E status of dairy cows at different stages of lactation. Livestock Production Science. In press.
SWALI, A., CHENG, Z., BOURNE, N. & WATHES, D. C. (2008) Metabolic traits affecting growth rates of pre-pubertal calves and their relationship with subsequent survival. Domest Anim Endocrinol 35, 300-313. PubMed ID 18675527
LLEWELLYN, S., FITZPATRICK, R., KENNY, D. A., PATTON, J. & WATHES, D. C. (2008) Endometrial expression of the insulin-like growth factor system during uterine involution in the postpartum dairy cow. Domest Anim Endocrinol 34, 391-402. PubMed ID 18258405
HAWORTH, G. M., TRANTER, W. P., CHUCK, J. N., CHENG, Z. & WATHES, D. C. (2008) Relationships between age at first calving and first lactation milk yield, and lifetime productivity and longevity in dairy cows. Vet Rec 162, 643-647. PubMed ID 18487583
FENWICK, M. A., LLEWELLYN, S., FITZPATRICK, R., KENNY, D. A., MURPHY, J. J., PATTON, J. & WATHES, D. C. (2008) Negative energy balance in dairy cows is associated with specific changes in IGF-binding protein expression in the oviduct. Reproduction 135, 63-75. PubMed ID 18159084
FENWICK, M. A., FITZPATRICK, R., KENNY, D. A., DISKIN, M. G., PATTON, J., MURPHY, J. J. & WATHES, D. C. (2008) Interrelationships between negative energy balance (NEB) and IGF regulation in liver of lactating dairy cows. Domest Anim Endocrinol 34, 31-44. PubMed ID 17137745
DERECKA, K., SHELDRICK, E. L., WATHES, D. C., ABAYASEKARA, D. R. & FLINT, A. P. (2008) A PPAR-independent pathway to PUFA-induced COX-2 expression. Mol Cell Endocrinol 287, 65-71. PubMed ID 18395968
WATHES, D. C., FENWICK, M., CHENG, Z., BOURNE, N., LLEWELLYN, S., MORRIS, D. G., KENNY, D., MURPHY, J. & FITZPATRICK, R. (2007) Influence of negative energy balance on cyclicity and fertility in the high producing dairy cow. Theriogenology 68 Suppl 1, S232-241. PubMed ID 17475319
WATHES, D. C., CHENG, Z., BOURNE, N., TAYLOR, V. J., COFFEY, M. P. & BROTHERSTONE, S. (2007) Differences between primiparous and multiparous dairy cows in the inter-relationships between metabolic traits, milk yield and body condition score in the periparturient period. Domest Anim Endocrinol 33, 203-225. PubMed ID 16806790
WATHES, D. C., BOURNE, N., CHENG, Z., MANN, G. E., TAYLOR, V. J. & COFFEY, M. P. (2007) Multiple correlation analyses of metabolic and endocrine profiles with fertility in primiparous and multiparous cows. J Dairy Sci 90, 1310-1325. PubMed ID 17297107
WATHES, D. C., ABAYASEKARA, D. R. & AITKEN, R. J. (2007) Polyunsaturated fatty acids in male and female reproduction. Biol Reprod 77, 190-201. PubMed ID 17442851
SWALI, A. & WATHES, D. C. (2007) Influence of primiparity on size at birth, growth, the somatotrophic axis and fertility in dairy heifers. Anim Reprod Sci 102, 122-136. PubMed ID 17097838
SHELDRICK, E. L., DERECKA, K., MARSHALL, E., CHIN, E. C., HODGES, L., WATHES, D. C., ABAYASEKARA, D. R. & FLINT, A. P. (2007) Peroxisome-proliferator-activated receptors and the control of levels of prostaglandin-endoperoxide synthase 2 by arachidonic acid in the bovine uterus. Biochem J 406, 175-183. PubMed ID 17516915
OLIVER, S. L., WOOD, E., ASOBAYIRE, E., WATHES, D. C., BRICKELL, J. S., ELSCHNER, M., OTTO, P., LAMBDEN, P. R., CLARKE, I. N. & BRIDGER, J. C. (2007) Serotype 1 and 2 bovine noroviruses are endemic in cattle in the United kingdom and Germany. J Clin Microbiol 45, 3050-3052. PubMed ID 17596356
LLEWELLYN, S., FITZPATRICK, R., KENNY, D. A., MURPHY, J. J., SCARAMUZZI, R. J. & WATHES, D. C. (2007) Effect of negative energy balance on the insulin-like growth factor system in pre-recruitment ovarian follicles of post partum dairy cows. Reproduction 133, 627-639. PubMed ID 17379657
LAVEN, R. A., WATHES, D. C., LAWRENCE, K. E. & SCARAMUZZI, R. J. (2007) An analysis of the relationship between plasma urea and ammonia concentration in dairy cattle fed a consistent diet over a 100-day period. J Dairy Res 74, 412-416. PubMed ID 17651532
LAVEN, R. A., SCARAMUZZI, R. J., WATHES, D. C., PETERS, A. R. & PARKINSON, T. J. (2007) Recent research on the effects of excess dietary nitrogen on the fertility of dairy cows. Vet Rec 160, 359-362. PubMed ID 17369475
CHENG, Z., SHELDRICK, E. L., MARSHALL, E., WATHES, D. C., ABAYASEKARA, D. R. & FLINT, A. P. (2007) Control of cyclic AMP concentration in bovine endometrial stromal cells by arachidonic acid. Reproduction 133, 1017-1026. PubMed ID 17616730
BOURNE, N., LAVEN, R., WATHES, D. C., MARTINEZ, T. & MCGOWAN, M. (2007) A meta-analysis of the effects of Vitamin E supplementation on the incidence of retained foetal membranes in dairy cows. Theriogenology 67, 494-501. PubMed ID 17007917
TAYLOR, V. J., BEEVER, D. E., BRYANT, M. J. & WATHES, D. C. (2006) Pre-pubertal measurements of the somatotrophic axis as predictors of milk production in Holstein-Friesian dairy cows. Domest Anim Endocrinol 31, 1-18. PubMed ID 16219444
SWALI, A. & WATHES, D. C. (2006) Influence of the dam and sire on size at birth and subsequent growth, milk production and fertility in dairy heifers. Theriogenology 66, 1173-1184. PubMed ID 16647111
SHELDON, I. M., WATHES, D. C. & DOBSON, H. (2006) The management of bovine reproduction in elite herds. Vet J 171, 70-78. PubMed ID 16427583
ROBINSON, R. S., FRAY, M. D., WATHES, D. C., LAMMING, G. E. & MANN, G. E. (2006) In vivo expression of interferon tau mRNA by the embryonic trophoblast and uterine concentrations of interferon tau protein during early pregnancy in the cow. Mol Reprod Dev 73, 470-474. PubMed ID 16435375
PATTON, J., KENNY, D. A., MEE, J. F., O'MARA, F. P., WATHES, D. C., COOK, M. & MURPHY, J. J. (2006) Effect of milking frequency and diet on milk production, energy balance, and reproduction in dairy cows. J Dairy Sci 89, 1478-1487. PubMed ID 16606718
MCMULLEN, S., OSGERBY, J. C., MILNE, J. S., WALLACE, J. M. & WATHES, D. C. (2005) The effects of acute nutrient restriction in the mid-gestational ewe on maternal and fetal nutrient status, the expression of placental growth factors and fetal growth. Placenta 26, 25-33. PubMed ID 15664408
ELMES, M., GREEN, L. R., POORE, K., NEWMAN, J., BURRAGE, D., ABAYASEKARA, D. R., CHENG, Z., HANSON, M. A. & WATHES, D. C. (2005) Raised dietary n-6 polyunsaturated fatty acid intake increases 2-series prostaglandin production during labour in the ewe. J Physiol 562, 583-592. PubMed ID 15513945
CHENG, Z., ELMES, M., KIRKUP, S. E., CHIN, E. C., ABAYASEKARA, D. R. & WATHES, D. C. (2005) The effect of a diet supplemented with the n-6 polyunsaturated fatty acid linoleic acid on prostaglandin production in early- and late-pregnant ewes. J Endocrinol 184, 165-178. PubMed ID 15642793
CHENG, Z., ABAYASEKARA, D. R. & WATHES, D. C. (2005) The effect of supplementation with n-6 polyunsaturated fatty acids on 1-, 2- and 3-series prostaglandin F production by ovine uterine epithelial cells. Biochim Biophys Acta 1736, 128-135. PubMed ID 16140575
TAYLOR, V. J., CHENG, Z., PUSHPAKUMARA, P. G., BEEVER, D. E. & WATHES, D. C. (2004) Relationships between the plasma concentrations of insulin-like growth factor-I in dairy cows and their fertility and milk yield. Vet Rec 155, 583-588. PubMed ID 15573950
TAYLOR, V. J., BEEVER, D. E., BRYANT, M. J. & WATHES, D. C. (2004) First lactation ovarian function in dairy heifers in relation to prepubertal metabolic profiles. J Endocrinol 180, 63-75. PubMed ID 14709145
OSGERBY, J. C., WATHES, D. C., HOWARD, D. & GADD, T. S. (2004) The effect of maternal undernutrition on the placental growth trajectory and the uterine insulin-like growth factor axis in the pregnant ewe. J Endocrinol 182, 89-103. PubMed ID 15225134
MCMULLEN, S., OSGERBY, J. C., THURSTON, L. M., GADD, T. S., WOOD, P. J., WATHES, D. C. & MICHAEL, A. E. (2004) Alterations in placental 11 beta-hydroxysteroid dehydrogenase (11 betaHSD) activities and fetal cortisol:cortisone ratios induced by nutritional restriction prior to conception and at defined stages of gestation in ewes. Reproduction 127, 717-725. PubMed ID 15175508
LAVEN, R. A., DAWUDA, P. M., SCARAMUZZI, R. J., WATHES, D. C., BIGGADIKE, H. J. & PETERS, A. R. (2004) The effect of feeding diets high in quickly degradable nitrogen on follicular development and embryo growth in lactating Holstein dairy cows. Anim Reprod Sci 84, 41-52. PubMed ID 15302386
ELMES, M., TEW, P., CHENG, Z., KIRKUP, S. E., ABAYASEKARA, D. R., CALDER, P. C., HANSON, M. A., WATHES, D. C. & BURDGE, G. C. (2004) The effect of dietary supplementation with linoleic acid to late gestation ewes on the fatty acid composition of maternal and fetal plasma and tissues and the synthetic capacity of the placenta for 2-series prostaglandins. Biochim Biophys Acta 1686, 139-147. PubMed ID 15522830
DAWUDA, P. M., SCARAMUZZI, R. J., DREW, S. B., BIGGADIKE, H. J., LAVEN, R. A., ALLISON, R., COLLINS, C. F. & WATHES, D. C. (2004) The effect of a diet containing excess quickly degradable nitrogen (QDN) on reproductive and metabolic hormonal profiles of lactating dairy cows. Anim Reprod Sci 81, 195-208. PubMed ID 14998647
CHENG, Z., ELMES, M., KIRKUP, S. E., ABAYASEKARA, D. R. & WATHES, D. C. (2004) Alteration of prostaglandin production and agonist responsiveness by n-6 polyunsaturated fatty acids in endometrial cells from late-gestation ewes. J Endocrinol 182, 249-256. PubMed ID 15283685
AYAD, V. J., LEUNG, S. T., PARKINSON, T. J. & WATHES, D. C. (2004) Coincident increases in oxytocin receptor expression and EMG responsiveness to oxytocin in the ovine cervix at oestrus. Anim Reprod Sci 80, 237-250. PubMed ID 15036500
WATHES, D. C., TAYLOR, V. J., CHENG, Z. & MANN, G. E. (2003) Follicle growth, corpus luteum function and their effects on embryo development in postpartum dairy cows. Reprod Suppl 61, 219-237. PubMed ID 14635938
TAYLOR, V. J., BEEVER, D. E., BRYANT, M. J. & WATHES, D. C. (2003) Metabolic profiles and progesterone cycles in first lactation dairy cows. Theriogenology 59, 1661-1677. PubMed ID 12559470
PUSHPAKUMARA, P. G., GARDNER, N. H., REYNOLDS, C. K., BEEVER, D. E. & WATHES, D. C. (2003) Relationships between transition period diet, metabolic parameters and fertility in lactating dairy cows. Theriogenology 60, 1165-1185. PubMed ID 12935855
OSGERBY, J. C., GADD, T. S. & WATHES, D. C. (2003) Effect of maternal body condition on placental and fetal growth and the insulin-like growth factor axis in Dorset ewes. Reproduction 125, 717-731. PubMed ID 12713435
OSGERBY, J. C., GADD, T. S. & WATHES, D. C. (2003) The effects of maternal nutrition and body condition on placental and foetal growth in the ewe. Placenta 24, 236-247. PubMed ID 12566251
CHENG, Z., ELMES, M., ABAYASEKARA, D. R. & WATHES, D. C. (2003) Effects of conjugated linoleic acid on prostaglandins produced by cells isolated from maternal intercotyledonary endometrium, fetal allantochorion and amnion in late pregnant ewes. Biochim Biophys Acta 1633, 170-178. PubMed ID 14499736
THORNTON, S., BALDWIN, P. J., HARRIS, P. A., HARDING, F., DAVISON, J. M., BAYLIS, P. H., TIMMONS, P. M. & WATHES, D. C. (2002) The role of arginine vasopressin in human labour: functional studies, fetal production and localisation of V1a receptor mRNA. BJOG 109, 57-62. PubMed ID 11843375
ROBINSON, R. S., PUSHPAKUMARA, P. G., CHENG, Z., PETERS, A. R., ABAYASEKARA, D. R. & WATHES, D. C. (2002) Effects of dietary polyunsaturated fatty acids on ovarian and uterine function in lactating dairy cows. Reproduction 124, 119-131. PubMed ID 12090925
PUSHPAKUMARA, P. G., ROBINSON, R. S., DEMMERS, K. J., MANN, G. E., SINCLAIR, K. D., WEBB, R. & WATHES, D. C. (2002) Expression of the insulin-like growth factor (IGF) system in the bovine oviduct at oestrus and during early pregnancy. Reproduction 123, 859-868. PubMed ID 12052240
OSGERBY, J. C., WATHES, D. C., HOWARD, D. & GADD, T. S. (2002) The effect of maternal undernutrition on ovine fetal growth. J Endocrinol 173, 131-141. PubMed ID 11927392
GADD, T. S., OSGERBY, J. C. & WATHES, D. C. (2002) Regulation of insulin-like growth factor binding protein-6 expression in the reproductive tract throughout the estrous cycle and during the development of the placenta in the ewe. Biol Reprod 67, 1756-1762. PubMed ID 12444050
ROBINSON, R. S., MANN, G. E., LAMMING, G. E. & WATHES, D. C. (2001) Expression of oxytocin, oestrogen and progesterone receptors in uterine biopsy samples throughout the oestrous cycle and early pregnancy in cows. Reproduction 122, 965-979. PubMed ID 11732992
LEUNG, S. T., CHENG, Z., SHELDRICK, E. L., DERECKA, K., FLINT, A. P. & WATHES, D. C. (2001) The effects of lipopolysaccharide and interleukins-1alpha, -2 and -6 on oxytocin receptor expression and prostaglandin production in bovine endometrium. J Endocrinol 168, 497-508. PubMed ID 11241181
CHENG, Z., ROBINSON, R. S., PUSHPAKUMARA, P. G., MANSBRIDGE, R. J. & WATHES, D. C. (2001) Effect of dietary polyunsaturated fatty acids on uterine prostaglandin synthesis in the cow. J Endocrinol 171, 463-473. PubMed ID 11739012
ROBINSON, R. S., MANN, G. E., GADD, T. S., LAMMING, G. E. & WATHES, D. C. (2000) The expression of the IGF system in the bovine uterus throughout the oestrous cycle and early pregnancy. J Endocrinol 165, 231-243. PubMed ID 10810287
LEUNG, S. T. & WATHES, D. C. (2000) Oestradiol regulation of oxytocin receptor expression in cyclic bovine endometrium. J Reprod Fertil 119, 287-292. PubMed ID 10864841
LEUNG, S. T., DERECKA, K., MANN, G. E., FLINT, A. P. & WATHES, D. C. (2000) Uterine lymphocyte distribution and interleukin expression during early pregnancy in cows. J Reprod Fertil 119, 25-33. PubMed ID 10864810
GADD, T. S., OSGERBY, J. C. & WATHES, D. C. (2000) Regulation and localization of insulin-like growth factor binding protein-5 gene expression in the uterus and placenta of the cyclic and early pregnant ewe. Biol Reprod 62, 1415-1421. PubMed ID 10775195
GADD, T. S., AITKEN, R. P., WALLACE, J. M. & WATHES, D. C. (2000) Effect of a high maternal dietary intake during mid-gestation on components of the utero-placental insulin-like growth factor (IGF) system in adolescent sheep with retarded placental development. J Reprod Fertil 118, 407-416. PubMed ID 10864806
ADAM, C. L., GADD, T. S., FINDLAY, P. A. & WATHES, D. C. (2000) IGF-I stimulation of luteinizing hormone secretion, IGF-binding proteins (IGFBPs) and expression of mRNAs for IGFs, IGF receptors and IGFBPs in the ovine pituitary gland. J Endocrinol 166, 247-254. PubMed ID 10927614
WATHES, D. C., BORWICK, S. C., TIMMONS, P. M., LEUNG, S. T. & THORNTON, S. (1999) Oxytocin receptor expression in human term and preterm gestational tissues prior to and following the onset of labour. J Endocrinol 161, 143-151. PubMed ID 10194538
ROBINSON, R. S., MANN, G. E., LAMMING, G. E. & WATHES, D. C. (1999) The effect of pregnancy on the expression of uterine oxytocin, oestrogen and progesterone receptors during early pregnancy in the cow. J Endocrinol 160, 21-33. PubMed ID 9854173
PERKS, C. M., PETERS, A. R. & WATHES, D. C. (1999) Follicular and luteal expression of insulin-like growth factors I and II and the type 1 IGF receptor in the bovine ovary. J Reprod Fertil 116, 157-165. PubMed ID 10505066
OSGERBY, J. C., GADD, T. S. & WATHES, D. C. (1999) Expression of insulin-like growth factor binding protein-1 (IGFBP-1) mRNA in the ovine uterus throughout the oestrous cycle and early pregnancy. J Endocrinol 162, 279-287. PubMed ID 10425467
MANN, G. E., LAMMING, G. E., ROBINSON, R. S. & WATHES, D. C. (1999) The regulation of interferon-tau production and uterine hormone receptors during early pregnancy. J Reprod Fertil Suppl 54, 317-328. PubMed ID 10692864
LEUNG, S. T., WATHES, D. C., YOUNG, I. R. & JENKIN, G. (1999) Effect of labor induction on the expression of oxytocin receptor, cytochrome P450 aromatase, and estradiol receptor in the reproductive tract of the late-pregnant ewe. Biol Reprod 60, 814-820. PubMed ID 10084953
LEUNG, S. T. & WATHES, D. C. (1999) Regulatory effect of steroid hormones and fetal tissues on expression of oxytocin receptor in the endometrium of late pregnant ewes. J Reprod Fertil 115, 243-250. PubMed ID 10434929
ABAYASEKARA, D. R. & WATHES, D. C. (1999) Effects of altering dietary fatty acid composition on prostaglandin synthesis and fertility. Prostaglandins Leukot Essent Fatty Acids 61, 275-287. PubMed ID 10670689
WATHES, D. C., REYNOLDS, T. S., ROBINSON, R. S. & STEVENSON, K. R. (1998) Role of the insulin-like growth factor system in uterine function and placental development in ruminants. J Dairy Sci 81, 1778-1789. PubMed ID 9684184
LEUNG, S. T., REYNOLDS, T. S. & WATHES, D. C. (1998) Regulation of oxytocin receptor in the placentome capsule throughout pregnancy in the ewe: the possible role of oestradiol receptor, progesterone receptor and aromatase. J Endocrinol 158, 173-181. PubMed ID 9771460
LANE, A. J. & WATHES, D. C. (1998) An electronic nose to detect changes in perineal odors associated with estrus in the cow. J Dairy Sci 81, 2145-2150. PubMed ID 9749379