Br. vet.
1. (1990) . 146, 165
SOME OBSERVATIONS ON THE EFFECTS OF AGE OF CALVES ON THE PHAGOCYTOSIS AND KILLING OF STAPHYLOCOCCUS A UREUS BY POLYMORPHONUCLEAR LEUCOCYTES
Z . WOLDEHIWET and T . G . ROWAN* Department of Veterinary Pathology and *Department of Animal Husbandry, University of Liverpool, Leahurst, Neston, South Wirral L64 7TE, UK
SUMMARY The effects of age on bovine polymorphonuclear (PMN) cell function were investigated by comparing the efficiencies of phagocytosis and killing of Staphylococcus aureus by peripheral blood leucocytes sequentially obtained from 15 calves between the ages of < 1 and 84 days . One group of seven calves was kept in a controlled environmental chamber with air temperature of 5 °C and 58% relative humidity (RH) and another group of eight calves was kept at 16 °C and 58% RH. The calves were given a diet a liquid milk substitute and dry food, and were weaned abruptly from the liquid diet at 35 days of age . The in-vitro efficiencies of phagocytosis, and of killing, Staphylococcus aureus by peripheral blood leucocytes were similar for calves in air temperatures of 5 °C and 16°C (P> 0. 05) . Peripheral blood leucocytes obtained from calves of less than 1 day of age were more efficient in phagocytosing S . aureus than those obtained when the same calves were 14-84 days of age (P< 0 . 001) . Peripheral blood leucocytes obtained when the calves were 42 and 56 days of age were significantly less efficient in phagocytosing and killing S . aureus than those obtained when the same calves were < 1, 14, 28, 70 and 84 days of age (P 0 . 05) .
DISCUSSION There have been few controlled experiments on the effects of age of calf and thermal environment on immune function in young calves . The winter weather and housing conditions of young calves in the United Kingdom are likely to represent conditions which are at least intermittently below thermoneutral (Williams, 1977) . The effective lower critical temperature of newborn calves either standing in still air or lying on wooden slats is about 11 ° C and lying in a deep, dry straw bed is about 6 ° C (Webster, 1984) . The effects of environment were confounded with the effects of group of calves . However, there were no indications of significant differences in bacterial phagocytosis, and in bacterial killing, by leucocytes between environments (groups of calves) at any ages of calves. The authors are not aware of other reports on the effects of thermal environment of animals on the in-vitro functions of phagocytes . The results suggest that the in-vitro phagocytosis and killing of bacteria by peripheral blood leucocytes were very efficient, being > 90% in calves < 1 day of age and > 80% in calves 14, 28 and 84 days . Hauser et al. (1986) found that PMN from unweaned calves of 4-5 weeks of age were significantly more efficient in phagocytosing S aureus in vitro than those from weaned calves of 9 weeks to 14 months of age (P< 0 . 05) . Renshaw et al. (1976) found no differences in the opsonic capacity of serum against S. aureus between newborn calves and adult cattle but adult cattle serum was able to opsonize E . coli more efficiently than that of newborn calf serum . The in-vitro efficiencies of phagocytosis, and of killing, of S . aureus by peripheral blood leucocytes decreased greatly between samples taken from calves at 28 and 42 days of age . At these ages the blood concentrations of PMN, the principal phagocyte, were also decreasing from the high concentrations in newborn calves . These decreases in PMN concentration are normal physiological events (Jain, 1986) . The calves were weaned abruptly at 35 days of age . This is a commonly used method and age of weaning calves in the United Kingdom . As the experiment did not include calves not weaned at 35 days of age, then whether or not the weaning either caused or contributed to the decreases in the in-vitro efficiencies of bacterial phagocytosis and bacterial killing by leucocytes is a moot
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point . If these in-vitro decreases were reflected in similar in-vivo decreases, then the point is worthy of further study as it may have considerable practical relevance to the prevention of disease in young calves . The recovery of preweaning levels of efficiency of bacterial phagocytosis and bacterial killing by leucocytes did not occur until between 56 and 70 days of age . Therefore, between the ages of approximately 4 and 10 weeks the calves may have been susceptible to infections normally prevented by efficient bacterial phagocytosis and bacterial killing by leucocytes. Roy et al. (1971) noted that calves weaned at 5 weeks of age had a higher incidence and severity of pneumonic lung lesions than calves given both a higher level and longer duration of milk feeding . Gwazdauskas et al. (1978) found in calves that antibody syntheses to heterologous erythrocytes were decreased by weaning . Crookshank et al. (1979) and Gwazdauskas et al. (1978) found that weaning caused increased serum glucocorticoid concentrations . Possibly the effects of weaning on immune responses, including bacterial phagocytosis and bacterial killing by leucocytes, are mediated by increased glucocorticoid concentrations (Kelley, 1980) .
ACKNOWLEDGEMENTS The technical support of T . Houghton, C . Savage and M . Savage is gratefully acknowledged .
REFERENCES COIGNOUL, F . L ., BERTRAM, T . A ., ROTH, J . A . & CHEVILLE, N . F. (1984) . American Journal of Veterinary Research 45, 898 . CROOKSHANK, H . R ., ELISSALDE, M . H ., WHITE, R. G ., CLANTON, D . C . & SMALLEY, H . E . (1979) . Journal of Animal Science 48, 430 . DUNCAN, D . B . (1955) . Biometrics 11, 1 . GWAZDAUSKAS, F . C ., GROSS, W . B ., BIBB, T . L . & MCGILLIARD, M . L . (1978) . Canadian Veterinary Journal 19, 150 . HAUSER, M . A ., Koos, M . D. & ROTH, J . A . (1986) . American Journal of Veterinary Research 47, 152 . JACOBSEN, K ., GINIz, T., REED, S . M ., NEWBRY, J ., BAYLY, W . M ., PERRYMAN, L . E . & WES LEID, R . (1982) . American Journal of Veterinary Research 43, 1912. JAIN, N . C . (1986) . Schalm's Veterinary Haematology, 4th edn, p . 178. Philadelphia : Lea and Febiger. KELLEY, K. W . (1980) . Annales de Recherches Vétérinaires 11, 445 . MILES, R. A., MISRA, S . S. & IRWIN, J . O . (1938). Journal of Hygiene 38, 732 . MILLER, M . E . (1969) . Journal of Paediatrics 74, 255 . RENSHAW, H . W ., ECKBLAD, W . P ., THACKER, D . L . & FRANK, F . W (1976) . American Journal of Veterinary Research 37, 1267 . ROTH, J . A . & KAEBERLE, M . L . (1981) . Veterinary Immunology and Immunopathology 2, 157 . RoY, J . H . B ., STOBo, I . J . F ., GASTON, H . J ., GANDERTON, P., SHOT"ION, S . M . & OSTLER, D . C . (1971) . British Journal of .Nutrition 26, 363 . SNEDECOR, G . W . & COCHRAN, W . G . (1980) . Statistical Methods, 7th edn, p . 144 . Ames : Iowa State
University Press . WEBSTER, A . J. F . (1984) . Calf Husbandry, Health and Welfare, p . 71 . London : Granada . WILLIAMS, M . R ., CRAVIN, N ., FIELD, T . R . & BUNCH, K. J . (1985) . British Veterinary journal 141, 362 . WILLIAMS, P . E . V . (1977) . PhD Thesis, Glasgow University . WOLDEHIWET, Z . (1987) . Journal of Comparative Pathology 97, 481 . (Accepted for publication 27May 1989)
1. (1990) . 146, 165
SOME OBSERVATIONS ON THE EFFECTS OF AGE OF CALVES ON THE PHAGOCYTOSIS AND KILLING OF STAPHYLOCOCCUS A UREUS BY POLYMORPHONUCLEAR LEUCOCYTES
Z . WOLDEHIWET and T . G . ROWAN* Department of Veterinary Pathology and *Department of Animal Husbandry, University of Liverpool, Leahurst, Neston, South Wirral L64 7TE, UK
SUMMARY The effects of age on bovine polymorphonuclear (PMN) cell function were investigated by comparing the efficiencies of phagocytosis and killing of Staphylococcus aureus by peripheral blood leucocytes sequentially obtained from 15 calves between the ages of < 1 and 84 days . One group of seven calves was kept in a controlled environmental chamber with air temperature of 5 °C and 58% relative humidity (RH) and another group of eight calves was kept at 16 °C and 58% RH. The calves were given a diet a liquid milk substitute and dry food, and were weaned abruptly from the liquid diet at 35 days of age . The in-vitro efficiencies of phagocytosis, and of killing, Staphylococcus aureus by peripheral blood leucocytes were similar for calves in air temperatures of 5 °C and 16°C (P> 0. 05) . Peripheral blood leucocytes obtained from calves of less than 1 day of age were more efficient in phagocytosing S . aureus than those obtained when the same calves were 14-84 days of age (P< 0 . 001) . Peripheral blood leucocytes obtained when the calves were 42 and 56 days of age were significantly less efficient in phagocytosing and killing S . aureus than those obtained when the same calves were < 1, 14, 28, 70 and 84 days of age (P 0 . 05) .
DISCUSSION There have been few controlled experiments on the effects of age of calf and thermal environment on immune function in young calves . The winter weather and housing conditions of young calves in the United Kingdom are likely to represent conditions which are at least intermittently below thermoneutral (Williams, 1977) . The effective lower critical temperature of newborn calves either standing in still air or lying on wooden slats is about 11 ° C and lying in a deep, dry straw bed is about 6 ° C (Webster, 1984) . The effects of environment were confounded with the effects of group of calves . However, there were no indications of significant differences in bacterial phagocytosis, and in bacterial killing, by leucocytes between environments (groups of calves) at any ages of calves. The authors are not aware of other reports on the effects of thermal environment of animals on the in-vitro functions of phagocytes . The results suggest that the in-vitro phagocytosis and killing of bacteria by peripheral blood leucocytes were very efficient, being > 90% in calves < 1 day of age and > 80% in calves 14, 28 and 84 days . Hauser et al. (1986) found that PMN from unweaned calves of 4-5 weeks of age were significantly more efficient in phagocytosing S aureus in vitro than those from weaned calves of 9 weeks to 14 months of age (P< 0 . 05) . Renshaw et al. (1976) found no differences in the opsonic capacity of serum against S. aureus between newborn calves and adult cattle but adult cattle serum was able to opsonize E . coli more efficiently than that of newborn calf serum . The in-vitro efficiencies of phagocytosis, and of killing, of S . aureus by peripheral blood leucocytes decreased greatly between samples taken from calves at 28 and 42 days of age . At these ages the blood concentrations of PMN, the principal phagocyte, were also decreasing from the high concentrations in newborn calves . These decreases in PMN concentration are normal physiological events (Jain, 1986) . The calves were weaned abruptly at 35 days of age . This is a commonly used method and age of weaning calves in the United Kingdom . As the experiment did not include calves not weaned at 35 days of age, then whether or not the weaning either caused or contributed to the decreases in the in-vitro efficiencies of bacterial phagocytosis and bacterial killing by leucocytes is a moot
1 70
BRITISH VETERINARY JOURNAL, 146 . 2
point . If these in-vitro decreases were reflected in similar in-vivo decreases, then the point is worthy of further study as it may have considerable practical relevance to the prevention of disease in young calves . The recovery of preweaning levels of efficiency of bacterial phagocytosis and bacterial killing by leucocytes did not occur until between 56 and 70 days of age . Therefore, between the ages of approximately 4 and 10 weeks the calves may have been susceptible to infections normally prevented by efficient bacterial phagocytosis and bacterial killing by leucocytes. Roy et al. (1971) noted that calves weaned at 5 weeks of age had a higher incidence and severity of pneumonic lung lesions than calves given both a higher level and longer duration of milk feeding . Gwazdauskas et al. (1978) found in calves that antibody syntheses to heterologous erythrocytes were decreased by weaning . Crookshank et al. (1979) and Gwazdauskas et al. (1978) found that weaning caused increased serum glucocorticoid concentrations . Possibly the effects of weaning on immune responses, including bacterial phagocytosis and bacterial killing by leucocytes, are mediated by increased glucocorticoid concentrations (Kelley, 1980) .
ACKNOWLEDGEMENTS The technical support of T . Houghton, C . Savage and M . Savage is gratefully acknowledged .
REFERENCES COIGNOUL, F . L ., BERTRAM, T . A ., ROTH, J . A . & CHEVILLE, N . F. (1984) . American Journal of Veterinary Research 45, 898 . CROOKSHANK, H . R ., ELISSALDE, M . H ., WHITE, R. G ., CLANTON, D . C . & SMALLEY, H . E . (1979) . Journal of Animal Science 48, 430 . DUNCAN, D . B . (1955) . Biometrics 11, 1 . GWAZDAUSKAS, F . C ., GROSS, W . B ., BIBB, T . L . & MCGILLIARD, M . L . (1978) . Canadian Veterinary Journal 19, 150 . HAUSER, M . A ., Koos, M . D. & ROTH, J . A . (1986) . American Journal of Veterinary Research 47, 152 . JACOBSEN, K ., GINIz, T., REED, S . M ., NEWBRY, J ., BAYLY, W . M ., PERRYMAN, L . E . & WES LEID, R . (1982) . American Journal of Veterinary Research 43, 1912. JAIN, N . C . (1986) . Schalm's Veterinary Haematology, 4th edn, p . 178. Philadelphia : Lea and Febiger. KELLEY, K. W . (1980) . Annales de Recherches Vétérinaires 11, 445 . MILES, R. A., MISRA, S . S. & IRWIN, J . O . (1938). Journal of Hygiene 38, 732 . MILLER, M . E . (1969) . Journal of Paediatrics 74, 255 . RENSHAW, H . W ., ECKBLAD, W . P ., THACKER, D . L . & FRANK, F . W (1976) . American Journal of Veterinary Research 37, 1267 . ROTH, J . A . & KAEBERLE, M . L . (1981) . Veterinary Immunology and Immunopathology 2, 157 . RoY, J . H . B ., STOBo, I . J . F ., GASTON, H . J ., GANDERTON, P., SHOT"ION, S . M . & OSTLER, D . C . (1971) . British Journal of .Nutrition 26, 363 . SNEDECOR, G . W . & COCHRAN, W . G . (1980) . Statistical Methods, 7th edn, p . 144 . Ames : Iowa State
University Press . WEBSTER, A . J. F . (1984) . Calf Husbandry, Health and Welfare, p . 71 . London : Granada . WILLIAMS, M . R ., CRAVIN, N ., FIELD, T . R . & BUNCH, K. J . (1985) . British Veterinary journal 141, 362 . WILLIAMS, P . E . V . (1977) . PhD Thesis, Glasgow University . WOLDEHIWET, Z . (1987) . Journal of Comparative Pathology 97, 481 . (Accepted for publication 27May 1989)
