Summary 1. A growing number of ecologists are turning to the enumeration of white blood cells from blood smears (leukocyte profiles) to assess stress in animals. There has been some inconsistency and controversy in the ecological literature, however, regarding their interpretation. The inconsistencies may stem partly from a lack of information regarding how stress affects leukocytes in different taxa, and partly from a failure on the part of researchers in one discipline to consult potentially informative literature from another. 2. Here, we seek to address both issues by reviewing the literature on the leukocyte response to stress, spanning the taxa of mammals (including humans), birds, amphibians, reptiles and fish. 3. We show that much of the early literature points to a close link between leukocyte profiles and glucocorticoid levels. Specifically, these hormones act to increase the number and percentage of neutrophils (heterophils in birds and reptiles), while decreasing the number and percentage of lymphocytes. This phenomenon is seen in all five vertebrate taxa in response to either natural stressors or exogenous administration of stress hormones. For the ecologist, therefore, high ratios of heterophils or neutrophils to lymphocytes (‘H : L’ or ‘N : L’ ratios) in blood samples reliably indicate high glucocorticoid levels. Furthermore, this close relationship between stress hormones and N : L or H : L ratios needs to be highlighted more prominently in haematological assessments of stress, as it aids the interpretation of results. 4. As with hormone assays, there are challenges to overcome in the use of leukocytes profiles to assess levels of stress; however, there are also advantages to this approach, and we outline each. Given the universal and consistent nature of the haematological response to stress, plus the overwhelming evidence from the veterinary, biomedical and ecological literature reviewed here, we conclude that this method can provide a reliable assessment of stress in all vertebrate taxa.

/pdf/the-use-of-leukocyte-profiles-to-measure-stress-in-43vg3davuy.pdf

The use of leukocyte profiles to measure stress in vertebrates: a review for ecologists

Rural Industries Research and Development Corporation

Intrauterine growth retardation (IUGR), defined as impaired growth and development of the mammalian embryo/fetus or its organs during pregnancy, is a major concern in domestic animal production. Fetal growth restriction reduces neonatal survival, has a permanent stunting effect on postnatal growth and the efficiency of feed/forage utilization in offspring, negatively affects whole body composition and meat quality, and impairs long-term health and athletic performance. Knowledge of the underlying mechanisms has important implications for the prevention of IUGR and is crucial for enhancing the efficiency of livestock production and animal health. Fetal growth within the uterus is a complex biological event influenced by genetic, epigenetic, and environmental factors, as well as maternal maturity. These factors impact on the size and functional capacity of the placenta, uteroplacental blood flows, transfer of nutrients and oxygen from mother to fetus, conceptus nutrient availability, the endocrine milieu, and metabolic pathways. Alterations in fetal nutrition and endocrine status may result in developmental adaptations that permanently change the structure, physiology, metabolism, and postnatal growth of the offspring. Impaired placental syntheses of nitric oxide (a major vasodilator and angiogenic factor) and polyamines (key regulators of DNA and protein synthesis) may provide a unified explanation for the etiology of IUGR in response to maternal undernutrition and overnutrition. There is growing evidence that maternal nutritional status can alter the epigenetic state (stable alterations of gene expression through DNA methylation and histone modifications) of the fetal genome. This may provide a molecular mechanism for the role of maternal nutrition on fetal programming and genomic imprinting. Innovative interdisciplinary research in the areas of nutrition, reproductive physiology, and vascular biology will play an important role in designing the next generation of nutrient-balanced gestation diets and developing new tools for livestock management that will enhance the efficiency of animal production and improve animal well being.

Board-invited review: intrauterine growth retardation: implications for the animal sciences.

The acute phase proteins (APP) are a group of blood proteins that contribute to restoring homeostasis and limiting microbial growth in an antibody-independent manner in animals subjected to infection, inflammation, surgical trauma or stress. In the last two decades, many advances have been made in monitoring APP in both farm and companion animals for clinical and experimental purposes. Also, the mechanism of the APP response is receiving attention in veterinary science in connection with the innate immune systems of animals. This review describes the results of recent research on animal APP, with special reference to their induction and regulatory mechanisms, their biological functions, and their current and future applications to veterinary diagnosis and animal production.

Current research on acute phase proteins in veterinary diagnosis: an overview.

The body's early defence in response to trauma, inflammation or infection, the acute phase response, is a complex set of systemic reactions seen shortly after exposure to a triggering event. One of the many components is an acute phase protein response in which increased hepatic synthesis leads to increased serum concentration of positive acute phase proteins. The serum concentration of these acute phase proteins returns to base levels when the triggering factor is no longer present. This paper provides a review of the acute phase proteins haptoglobin, C-reactive protein and serum amyloid A and their possible use as non-specific indicators of health in large animal veterinary medicine such as in the health status surveillance of pigs at the herd level, for the detection of mastitis in dairy cattle and for the prognosis of respiratory diseases in horses.

/pdf/application-of-acute-phase-protein-measurements-in-1n5ns21va9.pdf

Application of acute phase protein measurements in veterinary clinical chemistry.

An epidemiological study of wastage among racehorses was conducted in 1982 and 1983 among six stables, five of which were in Newmarket. The basis of the survey was the inability of horses to take part in cantering exercise as a result of injury or disease. The greatest number of days lost to training was caused by lameness (67.6 per cent) and respiratory problems (20.5 per cent). Conditions of the foot (19 pe cent), muscle (18 per cent), carpus (14 per cent), fetlock joints (14 per cent), tendons (10 per cent) and sore shins (9 per cent) were the major reasons for training days being lost in 198 cases in which a positive diagnosis of the site of lameness was made. The results confirm a previous investigation by Jeffcott and others (1982) and suggest that the diagnosis, therapy and prophylaxis of lameness merit a high priority in research efforts to reduce wastage among young racehorses.

Epidemiological study of wastage among racehorses 1982 and 1983.

Summary

This paper describes a collaborative project, conducted under the auspices of the British Equine Veterinary Association's survey section and financed by the Horserace Betting Levy Board, with the objective of collecting relevant data from breeding and racing statistics and evaluating losses (areas of wastage) that occur in the Thoroughbred racing industry. The investigation, which was carried out between 1977 and 1980, was divided into 2 parts. In Phase 1 the available statistics showed that considerable wastage existed from the time of covering to the appearance of the progeny on the flat, but that losses were closely consistent each year. Of the active mares in the General Stud Book for the seasons 1973 to 1979, 11.8 per cent were eliminated because no covering return was received and a further 10.1 per cent were either not covered, were covered by halfbreds or foaled abroad. The remaining mares, which were confirmed to have been covered (ie, applicable covered returned mares) were used to base the estimates of wastage. These were failure to conceive, 22.5 per cent, aborted or had a non-surviving foal, 10.1 per cent, live progeny not named, 13.9 per cent, named animals not trained (2 to 4) years), 20.1 per cent and trained animals that did not run at 2 to 4 years, 6.2 per cent.



This gave an overall figure for wastage of 72.8 per cent. Data on the numbers of outings as well as the numbers of animals imported and exported are quoted. An estimate of the cost of these losses was made under the following categories: lost stallion fees, keep of mares, keep of unnamed foals and keep of named animals that did not run. The cumulative losses for the 1974 season and its progeny was calculated to be at least £15.2 million.



Phase 2 examined more specifically some of the areas of wastage caused by breeding losses and the reasons for an unsatisfactory number of racing appearances. The most substantial reason for not competing or competing less than the average number of times was horses showing little or no ability to race. In a survey of 762 horses, 26.5 per cent did not race up to the age of 4 years; of these just over one third were being kept as “store” animals for National Hunt racing. The final part of the survey examined the veterinary reasons for wastage. In 314 horses in Newmarket, lameness was the most significant factor. There was an incidence of lameness of 53 per cent at some periods during the season and in 20 per cent of cases the lameness was sufficient to prevent racing afterwards.



Resume

Cet article produit les resultats d'une etude menee sous les auspices de la commission d'enquete de la BEVA, etude financee par le British Horserace Betting Levy Board. L'objectif de cette etude etait de reunir des informations utilisables a partir des statistiques des courses et de l'elevage afin d'evaluer les pertes et les points faibles de l'industrie des courses de pur sang.



Les recherches ont ete conduites entre 1977 et 1980. Les resultats sont exposes en deux parties. Dans la premiere, les statistiques disponibles ont montre qu'un deficit considerable se produit entre la periode de monte et l'apparition de la production sur l'hippodrome; les pertes sont du meme ordre chaque annee.



11.8% des poulinieres repertoriees au General Stud Book ont eteecartees de l‘etude parce qu'aucun renseignement sur la monte n'a ete renvoye. En outre 10% des poulinieres furent ou bien non saillies ou bien saillies par des demi sang, d'autres mettant bas a l’etranger. On a donc retenu pour servir de base a l'estimation le reliquat, c'est-a-dire celles des poulinieres dont les resultats de saillie furent officiellement confirmes (renseignements effectivement “retournes”).



Les resultats furent les suivants:



— vides (n'ayant pas concu): 22.5%



— avortees ou ayant eu un produit qui n'a pas vecu: 10%



— production vivante non nommee: 13.9% (anonymes)



— animaux nommes qui n'ont pas etea l'entrainement entre deux et quatre ans: 20.1%



— animaux entraines qui n'ont pas couru entre 2 et 4 ans: 6.2%



Au total le deficit s'eleve a 72.8% Les donnees se rapportant au nombre d'animaux importes et exportes sont fournies.



Une estimation du montant des pertes ainsi constatees a ete faite sous les rubriques suivantes: pertes sur les couts de saillie — pertes sur l'entretien des juments — pertes sur l'entretien des poulains anonymes — pertes sur l'entretien des chevaux qui n'ont pas couru.



Cumulees, les pertes pour la saison 1974 et pour ceux des animaux nes cette annee lâ ont ete estimes a plus de 15.2 millions de livres sterling.



Dans la seconde partie, on examine plus particulierement quelques unes des sources de deficit et les raisons du nombre insuffisant des sorties en course. La raison la plus importante pour ne pas courir ou pour courir moins souvent que la moyen ne est l'inaptitude pure et simple a la competition. Pour 762 chevaux on constate que 26.5% d'entre eux n'ont pu courir avant l‘âge de 4 ans. Parmi ceux-ci un peu plus d'un tiers fut conserve pour les programmes de courses a obstacles. La derniere partie de cette enquete etudie les raisons “veterinaires” du deficit. A Newmarket, pour 314 chevaux on a trouve que la boiterie etait le facteur le plus important. A un certain moment, on a constate 53% de boiteries durant la saison et dans 20% des cas les boiteries ont empeche le retour a la competition.



Zusammenfassung

Dieser Beitrag beschreibt eine gemeinsame Untersuchung, die von der BEVA uberwacht und vom Horserace Betting Levy Board finanziert worden ist. Es wurde die Absicht verfolgt, relevante Angaben aus Zucht- und Rennstatistiken zu sammeln und die Verluste, die im Vollblut-Rennbetrieb sich einstellen, auszuwerten. Die Untersuchung erstreckte sich uber die Jahre 1977 bis 1980 und wurde in zwei Teilen vorgenommen. Die zuganglichen Statistiken zeigten, dass in Phase 1 ein erheblicher Verschleiss sich bemerkbar macht zwischen der Deckzeit und dem Erscheinen des Nachwuchses in Flachrennen. Diese Verluste veranderten sich von Jahr zu Jahr kaum. Von den “aktiven” Stuten im General Stud Book wurden zwischen 1973 und 1979 11.8 Prozent eliminiert, weil das Deckergebnis nicht gemeldet wurde und weitere 10.1% wurden entweder nicht belegt oder durch Warmbluthengste gedeckt, oder sie fohlten ins Ausland ab. Die verbleibenden Stuten (Stuten mit bekannten Deckangaben und Abfohler-gebnissen) dienten zu einer Verschleissschatzung:



Keine Konzeption 22.5%



Abort oder nichtuberlebendes Fohlen 10.1%



lebendes, namenloses Fohlen 13.9%



Tiere mit Namen, aber nicht im Training zwischen 2 bis 4 Jahren 20.1%



Im Training, aber nicht im Rennen zwischen 2 bis 4 Jahren 6.2%



Das ergibt eine Verschleissrate von 72.8%. Es werden auch Angaben gemacht uber die Anzahl der bestrittenen Rennen und uber die Zahl importierter, beziehungsweise exportierter Pferde.



Eine Schatzung der durch diesen Verschleiss verursachten Kosten wurde in den folgenden Kategorien angestellt: verlorene Sprunggelder; Kosten der Stutenhaltung; Kosten der Haltung namenloser Fohlen; Haltungskosten fur nicht in Rennen eingesetzte Pferde. Die kumulierten Verluste fur die Decksaison 1974 und fur die Produktion aus dieser Saison wurden auf mindestens 15.2 Mio Pfund geschatzt.



In Phase 2 der Untersuchung wurden bestimmte Aspekte dieser Zuchtverluste spezifischer ausgewertet und die Grunde fur die unbefriedigende Anzahl bestrittener Rennen erforscht. Der wichtigste Grund dafur, dass viele Pferde uberhaupt nie auf die Rennbahn kommen oder nur an einer unterdurch-schnittlichen Anzahl von Rennen teilnehmen, besteht in einer fehlenden oder ungenugenden Eignung als Rennpferd. Von 762 Pferden bestritten 26.5% bis zu einem Alter von 4 Jahren uberhaupt keine Rennen; davon wurde nur etwas mehr als ein Drittel fur den Einsatz in Hindernisrennen “aufgespart”.



Im letzten Teil der Untersuchung wurden die tierarztlichen Grunde fur die Verluste unter die Lupe genommen. Bei 314 Pferden in Newmarket wurde Lahmheit als weit wichtigster Grund festgestellt. Wahrend der Rennsaison ergaben sich Perioden mit einer Lahmheitsfrequenz von 53%, wobei 20% der lahmen Pferde auch spater nicht mehr in Rennen eingesetzt werden konnten.

An assessment of wastage in thoroughbred racing from conception to 4 years of age

This study used gas chromatography/mass spectrometry (GC/MS) to identify and measure plasma progestagens. The method included deuterated internal standards, e.g. [17,21,21,21-2H]-5 alpha-pregnane-3,20-dione, solid-phase extraction, derivatization (methoxime/t-butyldimethylsilyl) and GC/MS. Full-scan screening identified 3 5-pregnenes, 2 4-pregnenes and 7 5 alpha-pregnanes (no 5 beta-pregnanes). The selected ion mode was used for routine quantitation from calibration curves; response was linear (r greater than 0.98) from 2 to 2000 ng equivalents/ml (0.5 ng/ml method sensitivity) and intra- and inter-assay coefficients of variation were less than 20%. The predominant steroids in plasma from pregnant pony and light-horse mares near term were 20 alpha-hydroxy-5 alpha-pregnan-3-one (400-2100 ng/ml) and 5 alpha-pregnane-3 beta,20 alpha-diol (100-350 ng/ml). Four other mono- and dihydroxy-5 alpha-pregnanes were generally between 30 and 100 ng/ml. These pregnanes were detectable initially between 30 and 60 days gestation and increased gradually until a more rapid increase was observed 30 days pre-partum. Maximum concentrations occurred during the last 2-3 days, followed by a decline before parturition. The progesterone profile during early pregnancy was similar to that given in previous reports. However, progesterone was not detectable during mid- to late pregnancy, except in a few mares near term (0.5-1 ng/ml). 5 alpha-Pregnane-3,20-dione (5 alpha-DHP) concentrations were similar to those of progesterone during early pregnancy but remained elevated and relatively constant (30 ng/ml) to term. No 20 alpha- or 20 beta-hydroxy-4-pregnen-3-one was detected in mare plasma. In mares that aborted or delivered prematurely, these pregnanes showed a profile of decreasing concentrations. In the fetal artery (250-300 days) plasma concentrations (ng/ml) of the predominant steroids were: pregnenolone (422), 5-pregnene-3 beta,20 beta-diol (171), 3 beta-hydroxy-5 alpha-pregnan-20-one (277) and 5 alpha-pregnane-3 beta,20 beta-diol (221). In the fetal vein, the predominant steroid was 5 alpha-DHP (205); progesterone was low (12.7 ng/ml) but consistently found. Steroids in the uterine venous plasma were similar in type and concentrations to those found in the peripheral circulation; uterine arterial concentrations were generally 50% lower. These results suggest that fetal pregnenolone is converted rapidly to progesterone and/or 5 alpha-DHP by the placenta, with further 3 beta- and 20 beta-hydroxylation by the fetus. In contrast, 20 beta-hydroxylation predominated on the maternal side and so may not directly reflect the fetal-placental environment.(ABSTRACT TRUNCATED AT 400 WORDS)

Plasma progestagens in the mare, fetus and newborn foal.

Adrenocortical and medullary function was investigated during the immediate post natal period in premature and full term foals. High plasma cortisol concentrations were characteristic of the term foals in the first 2 h after birth and these were accompanied by significant arteriovenous differences in plasma cortisol across the umbilical circulation at birth, indicating enhanced adrenal activity before delivery. No such arteriovenous differences were detected in the premature group and post natal changes in plasma cortisol were minimal. The apparent inability of the premature foal adrenal to secrete cortisol was not due to the lack of endogenous adrenocorticotrophic hormone (ACTH) because high levels of this hormone were found immediately after birth in both groups of foals. Tests on the sensitivity of the foal adrenal to exogenous ACTH1-24 (0.125 mg intramuscularly [im]) showed that a maximum response to this hormone could be elicited in term foals on the day of birth. Subsequently basal cortisol levels and the response of the adrenal to ACTH1-24 declined. By contrast, only a slight response was observed following the same dose of ACTH1-24 in the premature group. Exposure to Depot ACTH1-24 over 24 h enhanced the basal secretion of cortisol in both premature and term foals but no consistent response to the same ACTH test dose could be elicited in the former. A wide range of total plasma catecholamine concentrations was observed in both groups of newborn foals. The highest values were seen in acidotic animals and there was a significant inverse relationship between blood pH and total plasma catecholamine level at delivery.(ABSTRACT TRUNCATED AT 250 WORDS)

Studies on equine prematurity 2: Post natal adrenocortical activity in relation to plasma adrenocorticotrophic hormone and catecholamine levels in term and premature foals.

A sensitive and precise immunoassay for equine serum amyloid A protein (SAA) was established and used to determine, for the first time, the circulating concentration of this protein in health and disease. As in other species, equine SAA was present only at trace levels in healthy animals but behaved as an extremely sensitive and rapidly responding acute phase reactant following most forms of tissue injury, infection and inflammation, objectively reflecting the extent and activity of disease. Measurements of SAA should make a significant contribution to diagnosis and management of viral and bacterial infection in horses, and routine serial assays could provide an objective criterion for monitoring prospectively the general health of horses in training and racing.

P. D. Rossdale

Papers

Epidemiological study of wastage among racehorses 1982 and 1983.

An assessment of wastage in thoroughbred racing from conception to 4 years of age

Plasma progestagens in the mare, fetus and newborn foal.

Studies on equine prematurity 2: Post natal adrenocortical activity in relation to plasma adrenocorticotrophic hormone and catecholamine levels in term and premature foals.

Serum amyloid A protein (SAA) in horses: objective measurement of the acute phase response.