2 results
Effect of pasteurization at 76 and 63 °C on the absorption of colostral IgG in calves
- JEFF W. TYLER, JEFF LAKRITZ, DOUGLAS E. HOSTETLER, VICTORIA DOUGLAS, DUSTY M. WEAVER, BARRY J. STEEVENS, JULIE HOLLE, JOHN DENBIGH
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- Journal:
- Journal of Dairy Research / Volume 67 / Issue 4 / November 2000
- Published online by Cambridge University Press:
- 02 January 2001, pp. 619-623
- Print publication:
- November 2000
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The timely ingestion and absorption of colostral immunoglobulin is a critical determinant of neonatal calf health. Calves are born without appreciable concentrations of the serum immunoglobulins needed to protect against pathogenic bacteria, viruses and protozoa (Tyler & Parish, 1995). The beneficial effect of passive transfer of colostral immunoglobulin also extends beyond the neonatal period and persists into juvenile and adult life (Robison et al. 1988; Tyler et al. 1998; DeNise et al. 1989). Calves with failure of passive transfer, defined as serum protein < 50 g/l or serum IgG < 10 g/l, have increased mortality risks that persist until 10 weeks of age (Tyler et al. 1998).
Several diseases are potentially spread by the ingestion of colostrum, including bovine leukosis and Johne's disease (Perrin & Polack, 1988; Streeter et al. 1995). In one study 22% of latently infected cows were demonstrated to shed Mycobacterium paratuberculosis in their colostrum (Streeter et al. 1995). Optimal programmes to prevent and eradicate these diseases generally include the provision that calves are given colostrum derived from cows of known negative disease status. Pasteurization or heat treatment of colostrum may provide a mechanism whereby calves are provided with protection against neonatal disease without creating undue potential for infection by chronic, economically relevant diseases.
Attempts to heat disinfect colostrum are common in goat herds (MacKenzie et al. 1987). Pasteurization has been demonstrated to be effective against the caprine arthritis–encephalomyelitis virus (Adams et al. 1983; MacKenzie et al. 1987). Although Myco. paratuberculosis appears to resist pasteurization, this form of processing has been demonstrated to decrease the likelihood of positive colostral cultures for Myco. paratuberculosis under experimental conditions (Meylan et al. 1996). Sterilizing the milk and colostrum given to calves is a logical and reasonable strategy to prevent transmission of infectious microorganisms. The potential disadvantage of heat treating colostrum is that the immunoglobulins in colostrum may become denatured (Smith & Sherman, 1994). Pasteurization causes only a slight decrease in the colostral concentration of IgG in cattle (Meylan et al. 1996); however, the biological behaviour of these pasteurized immunoglobulins has not been critically examined. Therefore, we cannot be completely confident that immunoglobulin absorption, persistence in serum and biological activity are unchanged by this processing.
The goal of this study was to determine the effect of pasteurization at 76 and 63 °C on the absorption of IgG from colostrum. Should these procedures decrease immunoglobulin absorption, the use of pasteurization in disease eradication programmes would require increased efforts to optimize the passive transfer of immunoglobulin.
Modification of postmilking standing time by altering feed availability
- JEFF W. TYLER, BARRY J. STEEVENS, JULIE M. HOLLE, SEAN M. CROUCHER, KERRI L. ANDERSON
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- Journal:
- Journal of Dairy Research / Volume 65 / Issue 4 / November 1998
- Published online by Cambridge University Press:
- 01 November 1998, pp. 681-683
- Print publication:
- November 1998
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Control of environmental mastitis remains a problem on many modern dairy farms. These infections are often transmitted between milkings, and milking hygiene will not prevent new infection. Consequently, the control of environmental mastitis has prompted dairy managers to develop new approaches that either limit bacterial contamination of teat ends between milkings or directly increase the cow's resistance to infection. Intervention strategies that may decrease the incidence of environmental mastitis include improved sanitation of housing areas, decreased water use in udder preparation, optimal dietary concentrations of vitamin E and selenium, and use of R-mutant vaccines (Smith et al. 1984, 1985; Weiss et al. 1990; Smith & Hogan, 1993; Tyler et al. 1993).
Dairy managers are encouraged to provide cows with clean, fresh, palatable feed immediately after milking. This practice is thought to provide cows with an incentive to remain standing for an extended interval, permit teat sphincters to close, and limit teat end contamination and new infections when cows lie down. In one recent study, cows that had access to feed remained standing for a significantly longer time than did cows that were denied access to feed (48 v. 21 min; Tyler et al. 1997). The purpose of the present study was to substantiate that feed availability could be used to extend postmilking standing time in a larger population of cows maintained under different management conditions.