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Biomedical subjects

G H Stott

Publications and source records attributed to G H Stott.

16 recordsLinked to original sources
PubMed1989

Effects of passive immunity on subsequent production in dairy heifers.

Dairy Herd Improvement data from a large, commercial dairy farm were used to evaluate the relationships of first lactation milk and fat yield and age at first calving on passively acquired immunity in Holstein heifers. Total serum Ig concentration was measured 24 to 48 h postpartum (mean = 25.5 mg/ml, SD = 19.2) on calves allowed to suckle their dams freely through 24 h postpartum. No additional colostrum was supplied and no attempt was made to ensure adequate colostrum intake. Calves were raised in Tucson, AZ until 6 mo of age, then transferred to Idaho to complete the growing phase and to be bred. Heifers were returned to Tucson during their 7th or 8th mo of gestation. Serum Ig concentration, measured shortly after birth, was an important source of variation for mature equivalent milk (b = 8.5 kg/Ig unit) and mature equivalent fat (b = .24 kg/Ig unit) production in the first lactation but did not affect age at first calving. It is impossible to ascertain from these data whether Ig concentration at birth was directly or indirectly related to production; regardless, supplying an adequate amount and concentration of colostrum at the appropriate time to dairy heifers may enhance their future productivity.

Animals↗
PubMed1988

Effects of passive immunity on growth and survival in the dairy heifer.

Effects of 24 to 48 h serum Ig concentration on growth and survival of 1000 Holstein heifer calves were evaluated. Average serum Ig for all calves was 25.71 (SD = 19.06) mg/ml with a range of .05 to 108.27. Serum Ig concentrations were below 12 mg/ml in 28% of the heifers. Both season and age of dam contributed significantly to the variation in 24 to 48 h concentrations of serum Ig. Concentration of serum Ig at 24 to 48 h was a significant source of variation affecting average daily gain through the first 180 d of life. Seasonal factors also were significant in influencing rate of gain from birth to 180 d. Age of dam was a significant source of variation in calf weight gains but only for the first 35 d. Mortality was 6.78% for heifers with less than 12 mg/ml serum Ig at 24 to 48 h as compared with 3.33% mortality for calves with greater than 12 mg/ml concentration.

Animals↗
PubMed1979

Colostral immunoglobulin transfer in calves I. Period of absorption.

Termination or closure of intestinal permeability to colostral immunoglobulins in the calf occurs spontaneously with age at a progressively increased rate after 12 h postpartum. Following a normal distribution, mean closure occurred near 24 h postpartum when the calves were not fed. Feeding colostrum shortly after birth resulted in earlier cessation of absorption. The amount of colostrum fed had no influence on closure. A quadratic response surface analysis of starting time on closure showed a significant linear response in all immunoglobulin classes, indicating that as colostrum feeding is delayed, cessation also is delayed up to the time of spontaneous closure. Differences in closure time for the three immunoglobulin classes were not significant.

Animals↗
PubMed1979

Colostral immunoglobulin transfer in calves II. The rate of absorption.

The rate and pattern of colostral immunoglobulin absorption, based upon increase in concentration of immunoglobulin in serum in calves, has been determined from the interaction of three factors: starting age of colostral feeding, amount of colostrum fed, and time after feeding. All immunoglobulin classes show common characteristics of absorption following a rapid transfer during the first 4 h after feeding. An analysis of three-dimensional response surface for each of the three immunoglobulin classes indicated positive linear trend in the amount fed up to 2 liters. Rates of absorption in succeeding time periods following the initial feeding had decreasing linear trends. That is, age at first feeding had an inverse effect on rate of absorption. A linear-by-linear interaction between amount fed and starting age as shown for all three classes. Only immunoglobulin IgM had a significant quadratic response for amount fed. Concentration of immunoglobulin in the pooled colostrums fed had no influence on rate of absorption. Evidence is that 2 liters of colostrum fed to Holstein calves may be optimum in the range studied for maximum pinocytotic activation of absorptive cells and maximum rate of absorption.

Age Factors↗
PubMed1979

Colostral immunoglobulin transfer in calves. III. Amount of absorption.

Amount of colostrum fed and age at first feeding are the two major factors in determining maximum immunoglobulin concentration in serum for each immunoglobulin class in postcolostral calves. Both factors show linear response: increasing age, decreasing concentration; increasing amount fed up to 2 liters, increasing concentration. The two factors interact in a curvilinear response. Calves with initial feeding at progressively older ages need less colostrum to reach maximum absorption. Maximum absorption is represented by a progressively lower immunoglobulin concentration in serum with increasing age. Response surface contours for the maximum immunoglobulins IgG, IgM, and IgA, based on experimental data, have been included. Neither body weights of the experimental calves nor pooled colostral concentrations of immunoglobulin from pooled colostrums fed to the calves influenced maximum concentrations of immunoglobulin in serum.

Agammaglobulinemia↗
PubMed1979

Colostral immunoglobulin transfer in calves. IV. Effect of suckling.

The greater absorption of colostral immunoglobulin in neonate calves suckling their dams over bottle-feeding pooled colostrum was studied to determine if age (hours postpartum) at initial feeding, amount of colostrum ingested, or mothering effect of being with the dam were responsible. Rate of absorption and maximum absorption were superior in calves that suckled, regardless of age or amount of colostrum ingested. Though the mothering effect is questionable, there is evidence that something labile is being transferred to the calf in the fresh colostrum, acting as a messenger to stimulate rapid absorptive activity in the intestinal epithelium.

Age Factors↗
PubMed1978

Selective absorption of immunoglobulin IgM in the newborn calf.

The efficiency of absorption of colostral immunoglobulin classes was determined by the ratio of the quantity of immunoglobulins in the calf serum after absorption was complete to the quantity in the colostrum fed the calves. The experiment with 58 pooled colostrums assayed for absorbability of immunoglobulins had three to eight calves per assay. Colostrums with similar concentrations of immunoglobulins varied from 10 to 46% in absorption of IgG and 5 to 50% in IgA. The percent of immunoglobulin IgM absorbed increased as the amount ingested decreased. The absorption efficiencies of immunoglobulins IgA and IgG did not change as intake varied. Correlations of colostral immunoglobulins ingested with percent absorption in summaries of two experiments were -.76 and -.90 for IgM, 0 and -.33 for IgG, and -.05 and -.02 for IgA. The selective transport of IgM is important for its role as the primary immunoglobulin giving the calf immune protection during the first few days of life. The variation in absorption of IgM in different colostrums of similar immunoglobulin content was not different from that among calves receiving the same colostrum.

Animals↗
PubMed1978

Adrenal function and passive immunity in the dystocial calf.

Dystocial calves were tested for their ability to absorb colostral immunoglobulins and establish a competent passive immunity. Twenty dystocial and 20 eutocial calves were fed 1 liter of colostrum 4 h after birth and an additional liter 12 h later. Their absorption of the immunoglobulins A, G, and M, as indicated by serum concentrations, was equivalent at 16 and 24 h postpartum. Cortisol concentrations in serum at birth were high in both eutocial and dystocial calves and were correlated negatively with environmental temperatures prior to parturition. The dystocial calves had a lower cortisol concentration in serum at birth. The differences in cortisol concentrations between dystocial and eutocial calves and between experimental blocks influenced by environmental temperature could not be related to immunoglobulin absorption.

Adrenal Glands↗
PubMed1977

Prepartum serum hormone concentrations related to dystocia in Holstein heifers.

Twelve Holstein heifers from a herd having a high incidence of dystocia were bled each day at 0730 h from 260 days gestation until parturition. The blood was analyzed for estradiol-17beta, estrone, 17-hydroxyprogesterone, progesterone, and corticosteroids. Six of the animals had dystocia. The concentrations of estradiol-17beta were lower and the concentration of progesterone higher in dystocial animals during the prepartum period from 23 to 12 days. The prepartum patterns of secretion of corticosteroid, estrone, and 17-hydroxyprogesterone did not change significantly in the two groups between days 23 and 12 prepartum. The prepartum difference in serum estradiol-17beta and progesterone concentration between normal and dystocial animals suggests that the timing of hormone changes in preparation for parturition is delayed and not as pronounced in dystocial animals.

Adrenal Cortex Hormones↗
PubMed1976

Effect of stress on blood leucocyte and milk somatic cell counts in dairy cows.

Blood and milk samples from Holstein cows were examined for total blood leucocyte count, differential blood leucocyte count, milk quality test, and somatic cell count in milk while the cows were stressed by corticotropin injection, confinement in a heat-humidity chamber, or environmental-heat stress by exposure during the hot summer months of June through November in southern Arizona. All three stressing conditions resulted in a moderate blood leucocytosis. Modest increases in somatic cell counts of milk were associated with corticotropin injection and environmental-heat stress. Positive correlations were recorded between blood leucocytes and somatic cell counts of milk in mastitis-free cows injected with corticotropin and between percent blood neutrophils and somatic cell counts of milk in environmental-heat stressed cows with no evidence of current mastitis.

Adrenocorticotropic Hormone↗
PubMed1976

Influence of environment on passive immunity in calves.

Passive immunity in neonatal calves is influenced by environment. Placing newly born Holstein calves (108 head) in three different housing environments (shade, cooled shade, hutch) during hot weather produced differences in body temperature, serum cortocosteroids, immunoglobulin IgG1 concentrations, and mortality. Experimental design permitted examination of effects due to treatments, time, differences in colostrum, and climatic environment in an analysis of variance. Calves exposed to the hotter, less desirable environment responded by having a higher mortality, higher serum corticosteroid concentration, and lower serum immunoglobulin IgG1 at 2 and 10 days after birth. All of these were correlated. Calves that died had serum immunoglobulin IgG1 falling below the mean for all experimental calves.

Adrenal Cortex Hormones↗