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We examined the relationship between serum gamma glutamyltransferase (GGT) activity and serum gamma immunoglobulin G (IgG1) concentration in Holstein calves. Blood samples were collected from calves aged 1 to 3 days. A follow-up sample was obtained from each calf 2, 7, or 15 days after the initial sampling. Serum GGT activity and lgGl concentration were measured. Regression models were used to predict lgGl concentration as a function of age and serum GGT activity measured 2, 7, or 15 days later.Serum GGT activity and calf age at the time of the second sample were directly related to serum lgGl concentration alves are born with negligible concentrations of serum C immunoglobulins. The absorption of colostral immunoglobulins provides calves with an external source of protective antibodies until they mount active, protective immune responses.'-3 The process of immunoglobulin acquisition is termed colostral passive transfer. Absorption of immunoglobulins is nonselective, and nonimmunoglobulin proteins present in colostrum also are readily absorbed. One such protein that is present in high concentrations in bovine colostrum is gamma glutamyltransferase (GGT).4Measurement of serum immunoglobulins most accurately reflects the efficacy of passive transfer when sampling is performed between 36 and 48 hours after birth.' Prior to this time, serum immunoglobulin concentration still is increasing as a result of ingestion and absorption of colostral antibodies.After this period of colostrum ingestion and immunoglobulin absorption, catabolism and excretion of immunoglobulins cause a decline in circulating antibody concentrations.Several diagnostic procedures have been developed to assess the success of passive transfer,' including serum refractometry, zinc sulfate and sodium sulfite turbidity assays, and radial immunodiffusion.' Serum GGT activity may be an additional useful method to assess passive transfer in calves.Several studies have demonstrated GGT activity in bovine milk and colostrum and the colostral passive transfer of GGT activity to calves."* The enzyme GGT has a molecular weight of 80,000 daltons and is readily absorbed by the newborn calf. Colostral GGT activities are approximately 800-fold greater than serum GGT in the same COWS.^ Serum GGT activities in calves that have suckled and absorbed colostrum are 60 to 160 times greater than normal adult activities and slowly decline to adult activities by 5 weeks of age.G7 Calves that do not ingest and absorb colostrum have serum GGT activities similar to those observed in normal adult cattle. Both colostrum and milk contain GGT, but activities in milk are considerably lower than those in Feeding of milk replacers or boiled milk results in only slight increases in serum GGT activity in colostrumdeprived calves.' Consequently, measurement of serum GGT activity in the early neonatal period may be a useful predictor of passive transferThe purpose of this study was to determine whether serum GGT activity could be used to predict the serum gamma immunoglobulin G (IgG1) co...

The relationship between serum protein concentration in the 1st week of life and survival to 16 weeks of age was examined in 3,479 Holstein replacement heifers over a period of 10 years on a farm with endemic salmonellosis. Thirty-four percent of calves studied had serum protein concentrations <5.0 g/dL and 60.5% of calves had serum protein concentrations <5.5 g/dL. Cumulative mortality was 7.9%, indicating that calves with marginal passive transfer status can be reared successfully under conditions of endemic salmonellosis. Optimal survival was observed in calves with serum protein concentrations >5.5 g/dL. Calves with serum protein concentrations of 5.0-5.4 g/dL had only a slightly increased relative risk (RR) of mortality (RR = 1.3) compared to calves with serum protein concentrations >5.5 g/dL. The highest RR was experienced by calves with serum protein concentrations <4 g/dL (RR = 4.6) and 4.0-4.4 g/dL (RR = 3.1). Calves with inadequate passive transfer (serum protein concentration <5.0 g/dL), experienced increased mortality until at least 10 weeks of age, indicating that failure of passive transfer has an effect on calf health that extends into the juvenile period. Models in which serum protein concentration was treated either as a continuous variable or as a categorical variable failed to demonstrate any significant interaction between baseline mortality and the RR of mortality. This finding suggests that the RR derived in the present study should be applicable to farms with dramatically different baseline mortality rates.Key words: Calves; Colostrum; Passive transfer; Refractometry; Serum proteins.revious studies have shown that refractometry is an ac-P curate predictor of passive transfer status in young calves. Reported r' values for models predicting serum immunoglobulin G (IgG) concentration as a function of serum protein concentration range from 0.6 to OX.'-' Accuracy of refractometry in prediction of calf health and survival has been less clear. Although calves with low serum protein or immunoglobulin concentrations generally are accepted to be at greater risk for morbidity and mortality,4-I1 some studies have failed to identify any significant increase in risk associated with lower serum protein or immunoglobulin concentrations.12J3 In some instances, small sample size was hypothesized as a primary cause for the failure to identify increased risk of m0rta1ity.l~ The purpose of this study was to characterize the association between passive transfer status, as determined by refractometric determination of serum protein concentration, and mortality in mixed-source dairy replacement heifers. Furthermore, this study examined whether the relationship between passive transfer status and mortality was dependent or independent with regard to baseline mortality risk in calves. Lastly, the present study attempted to determine the upper age limit at which inadequate passive transfer status was related to the ongoing risk of mortality. Materials and Methods Study SiteThe study farm was a contract calf-rearing ...

Summary The individual merit of the use of 43 variables to assess the prognosis of equine colic cases was examined. The following variables revealed highly significant (P<0.001) differences between cases which survived and those which died: blood pressure; heart rate; oral mucosal capillary refill time; degree of mental depression; venous haemogloblin concentration, haematocrit, erythrocyte count, urea concentration and lactate concentration; peritoneal fluid lactate concentration; and haematocrit/plasma protein and serum protein concentration ratios. Thus, in general, variables which assessed cardiovascular function were good prognostic guides. Résumé On discute de la validité individuelle de 43 variables utilisées pour asseoir le pronostic des coliques du cheval. Les variables suivantes paraissent avoir une bonne valeur (P<0.001) pour différencier les cas mortels de ceux pouvant survivre: la pression sanguine, le rythme cardiaque, le temps de remplissage des capillaires, de la muqueuse buccale, le degré de dépression psychique, la concentration veineuse en hémoglobine, l'hématocrite, le nombre d'hématies, la concentration en urée sanguine, la concentration en acide lactique (lactates), la concentration du liquide péritonéal en lactates, le rapport entre l'hématocrite et le taux des protéines sériques et plasmatiques. Ainsi, en général, les variables qui permettent d'apprécier la fonction cardio vasculaire ont été de bonne valeur pronostique. Zusammenfassung Die individuelle Zuverlässigkeit von 43 Variablen bei der Prognosestellung in Kolikfällen wurde untersucht. Die folgenden Variablen zeigten hochsignifikante Unterschiede (P<0.001) zwischen überlebenden und eingegangenen Fällen: Blutdruck; Herzfrequenz; Kapillarfüllungszeit der Maulschleimhaut; Grad der Apathie; venöse Haemoglobinkonzentration, Haematokrit, Erythrozytenzahl; Harnstoff‐ und Laktatkonzentration, Laktatkonzentration in Peritonaealflüssigkeit, Verhältnis von Haematokrit zu Plasmaprotein und Serum‐protein konzentration. Demnach erweisen sich diejenigen Variablen als prognostisch wertvoll, die die cardiovaskuläre Funktion zu erfassen erlauben.