This paper presents the report of a committee of the American Association of Bovine Practitioners... more This paper presents the report of a committee of the American Association of Bovine Practitioners recommending methods for calculating several basic indices of reproductive performance on dairy farms. Indices for several major analytic areas are presented: overall reproductive performance, estrus detection intensity, conception efficiency, pregnancy losses, reproductive culling, and also reproductive efficiency in herds using a bull.
This paper presents the report of a committee of the American Association CALCULATING REPRODUCTIV... more This paper presents the report of a committee of the American Association CALCULATING REPRODUCTIVE INDICES 79 of Bovine Practitioners recommending methods for calculating several basic indices of reproductive performance on dairy farms. Indices presented are: overall reproductive performance, intensity of estrus detection, conception efficiency, pregnancy losses. reproductive culling, and reproductive efficiency in herds using a bull. Data from a hypothetical dairy herd are provided and example indices are calculated.
The Canadian veterinary journal. La revue vétérinaire canadienne, 1997
The objectives of this study were to estimate the prevalence of bacteremia in critically ill, neo... more The objectives of this study were to estimate the prevalence of bacteremia in critically ill, neonatal calves with severe diarrhea or depression, and to describe the variety of bacteria involved. Two studies were conducted in the summers of 1991 and 1993 involving 190 neonatal calves, 1-day to 19-days-old. Bacteremia was detected by blood culture in 31% (28/90) of calves in study 1, and in 24% (19/79) of ill calves and 0% (0/21) of control calves in study 2. Bacteria cultured from blood included Escherichia coli (51% of all isolates), other gram-negative enterics (25.5%), gram-negative anaerobes (5.9%), gram-positive cocci (11.8%), and gram-positive rods (5.9%). Among clinically ill calves, the average age was significantly lower in the blood culture-negative group (5.5 d) than in the blood culture-positive group (7.5 d) (P = 0.004). Mean serum IgG concentration was significantly (P = 0.0001) lower in blood culture-positive calves (1.146 g/L) than in blood culture-negative calves (3...
ABSTRACTObjective. To compare four different dry cow treatments (DCT) and establish their effecti... more ABSTRACTObjective. To compare four different dry cow treatments (DCT) and establish their effectiveness in reducing intramammary infections (IIM). Materials and methods. DCTs included systemic tylosin (12g) alone or accompanied by cefapirine intramammary infusions and or an internal teat sealant. A total number of 278 cows at the end of lactation period were randomly assigned to one of 4 dry cow treatment groups: CESE Group (n=89), intramammary cephapirin and teat sealant. TYCESE Group (n=84), intramammary cephapirin, tylosin 12 g intramuscular and teat sealant. TYSE Group (n=86), 12 g intramuscular tylosin and teat sealant; TY Group (n=76) 12 g intramuscular tylosin only. Milk samples for culture were collected at dry-off and 1 and 2 weeks after calving. Somatic cell counts (SCC) were taken from Dairy Herd Improvement Association (DHI) tests at dry-off, and the first two test days after calving. Results. Bacteria cure rate for Gram-positive intramammary infections (IMI) for TYCESE ...
Animal health research reviews / Conference of Research Workers in Animal Diseases, 2014
The primary source of data on bovine respiratory disease (BRD) prevalence in US adult dairy cattl... more The primary source of data on bovine respiratory disease (BRD) prevalence in US adult dairy cattle is producer surveys, which estimate that 2.4-2.9% of cattle are affected. This estimate appears low when compared to calculations based on limited data regarding on-farm deaths due to BRD and the number of carcasses at slaughter with severe BRD. These calculations indicate that approximately 3% of dairy cows die on farm or go to slaughter with severe BRD. Not included in these data are cows that are treated for BRD and retained. The primary manifestation of BRD on dairy farms is in calves. Nationwide surveys have estimated that 12.4-16.4% of preweaned dairy heifer calves are affected with BRD, and 5.9-11% of calves are affected after weaning. More detailed prevalence studies have generally included a limited number of small farms, with limited calf age range studied. All studies relied on producer diagnosis. Prevalence in these studies ranged from 0 to 52%, with many cases occurring be...
The Canadian veterinary journal. La revue vétérinaire canadienne, 1997
In human, equine, and bovine neonates, early diagnosis of bacteremia remains a challenge for the ... more In human, equine, and bovine neonates, early diagnosis of bacteremia remains a challenge for the internist. The objective of this study was to develop a predictive model for risk of bacteremia, based on a clinical evaluation system called the clinical sepsis score. Blood from 90 ill calves, 1- to 14-days-old from a calf-raising farm in the San Joaquin Valley of California was cultured. The calves were also scored according to a clinical score for hydration status, fecal appearance, general attitude, appearance of scleral vessels, and umbilical abnormality. Age, rectal temperature, heart rate, respiratory rate, and presence or absence of a focal site of infection were recorded. Prevalence of bacteremia was 31% (28/90). A logistic regression model indicated that high clinical score, presence of a focal infection, and increased age were associated with an increased risk of bacteremia in ill calves (P < 0.06). Calves for which the model predicted bacteremia with a probability > or...
Journal of the American Veterinary Medical Association, Jan 15, 1977
In a fecal examination survey (1975-1976) of 217 cats from laboratory colonies, a humane society ... more In a fecal examination survey (1975-1976) of 217 cats from laboratory colonies, a humane society shelter, and homes in east central Illinois, Toxocara mystax eggs were found in 32%, Toxascaris leonina eggs in 6%, Ancylostoma eggs in 9%, Capillaria eggs in 4%, Isospora felis oocysts in 23%, Isospora rivolta oocysts in 24%, and Toxoplasma or Besnoitia oocysts in 1%. The laboratory and humane shelter cats were the most heavily infected. Isospora felis and I rivolta could not be transmitted to 2 pups by feeding oocysts from the cat or to 2 other pups by feeding the organs of mice that had been fed the oocysts.
For three California dairy herds with bulk tank SCC &amp;amp;lt; 200,000/ml, twice daily milk... more For three California dairy herds with bulk tank SCC &amp;amp;lt; 200,000/ml, twice daily milking, and no mastitis vaccine, 254 quarters with mild clinical mastitis were randomly assigned to three groups. Group A (n = 74) was treated with 62.5 mg of intramammary amoxicillin every 12 h for three milkings. Group C (n = 75) was treated with 200 mg of intramammary cephapirin every 12 h for two milkings. Group O (n = 105) was treated with 100 units of intramuscular oxytocin every 12 h for two or three milkings. Aseptic pretreatment quarter samples revealed 94 (37%) coliforms, 65 (26%) environmental streptococci, 34 (13%) other bacteria, and 61 (24%) with no isolate on bovine blood agar plates. Contagious pathogens were not isolated. Clinical cure (return of quarter and milk to normal) and bacterial cure (absence of primary pathogen isolated pretreatment) were assessed at milking 8 and d 20 after initial treatment. No difference existed in clinical (67.6, 67.7, or 66.7%) or bacterial (43.9, 55.0 or 49.1%) cure rate among groups. Clinical cure rates did not differ when quarters were grouped by etiology, but clinical cure rates for quarters with pathogens other than streptococci or coliforms were lower in group O.
For two large California dairy herds with twice daily milking, 171 infected quarters of lactating... more For two large California dairy herds with twice daily milking, 171 infected quarters of lactating cows with mild clinical mastitis were randomly assigned to one of three treatment groups. Group A (50 cows) was treated with 62.5 mg of intramammary amoxicillin every 12 h for three milkings. Group C (50 cows) was treated with 200 mg of intramammary cephapirin every 12 h for two milkings. Group 0 (71 cows) was treated with 100 U of intramuscular oxytocin every 12 h for three milkings. Clinical cure rates did not differ among treatment groups. The cost per episode of clinical mastitis was higher ($54.47) for group C than for groups A ($38.53) or 0 ($34.88). Group 0 had a higher incidence of relapse (41%), and a greater percentage of group 0 cows (65%) experienced an additional mastitic event in the enrolled lactation than did cows in groups A and C. Treatment had no effect on the mean number of nonsalable milkings (24.7) associated with mastitis in the lactation interval subsequent to enrollment on the trial. Twenty-two percent of the cows accrued more than 30 nonsalable milkings and produced 55% of the total nonsalable milkings associated with mastitis. There was no treatment effect on total milk
This paper presents the report of a committee of the American Association CALCULATING REPRODUCTIV... more This paper presents the report of a committee of the American Association CALCULATING REPRODUCTIVE INDICES 79 of Bovine Practitioners recommending methods for calculating several basic indices of reproductive performance on dairy farms. Indices presented are: overall reproductive performance, intensity of estrus detection, conception efficiency, pregnancy losses. reproductive culling, and reproductive efficiency in herds using a bull. Data from a hypothetical dairy herd are provided and example indices are calculated.
Journal of the American Veterinary Medical Association, Jan 15, 1992
An epizootic of subclinical and clinical mastitis caused by Serratia marcescens was investigated ... more An epizootic of subclinical and clinical mastitis caused by Serratia marcescens was investigated in a 1,000-cow dairy farm in California. Serratia marcescens was isolated from 13 to 18% of composite milk samples obtained from lactating dairy cows. During monthly milk sampling performed during a 4-month period, S marcescens was isolated from 38.8 to 62.3% of composite milk samples obtained from cows from which S marcescens was previously isolated. Few cows infected with S marcescens had evidence of clinical mastitis. Somatic cell count value was associated with isolation of S marcescens. Cows with somatic cell counts greater than 500,000 were 5.48 times as likely to have intramammary infections with S marcescens, compared with cows with somatic cell count less than or equal to 500,000. Lactation number also was associated with S marcescens intramammary infection. After adjusting for the effect of lactation number, cows with high somatic cell count values were 2.98 times as likely to ...
Feeding a high concentration of cotton seed meal to young calves resulted in death with lesions c... more Feeding a high concentration of cotton seed meal to young calves resulted in death with lesions compatible with gossypol toxicity. Calves were fed two different commercially prepared rations. Free gossypol concentrations in different lots of the 17% protein ration vaned from 250 to 380 ppm, and the 13% protein ration varied from 40 to 240 ppm. Serum sorbitol dehydrogenase elevation was the most consistent clinical pathological finding. The mean serum sorbitol dehydrogenase concentrations for moribund, hospitalized, and clinically healthy calves were 277, 34, and 45 units/liter. The mean for sorbitol dehydrogenase concentration for healthy calves not fed cotton seed meal was 18 units/liter. Gross lesions included severe effusion of a high protein content fluid into the body cavities of most calves, edema of the mesentery, and hepatomegaly. The most consistent histological lesion was severe centrilobular hepatic necrosis. Elevated levels of liver gossypol were demonstrated. The mean liver gossypol concentration for three calves was 4 1.7 Fglg on a wet weight basis.
The Canadian veterinary journal. La revue vétérinaire canadienne, 1997
The objectives of this study were to estimate the prevalence of bacteremia in critically ill, neo... more The objectives of this study were to estimate the prevalence of bacteremia in critically ill, neonatal calves with severe diarrhea or depression, and to describe the variety of bacteria involved. Two studies were conducted in the summers of 1991 and 1993 involving 190 neonatal calves, 1-day to 19-days-old. Bacteremia was detected by blood culture in 31% (28/90) of calves in study 1, and in 24% (19/79) of ill calves and 0% (0/21) of control calves in study 2. Bacteria cultured from blood included Escherichia coli (51% of all isolates), other gram-negative enterics (25.5%), gram-negative anaerobes (5.9%), gram-positive cocci (11.8%), and gram-positive rods (5.9%). Among clinically ill calves, the average age was significantly lower in the blood culture-negative group (5.5 d) than in the blood culture-positive group (7.5 d) (P = 0.004). Mean serum IgG concentration was significantly (P = 0.0001) lower in blood culture-positive calves (1.146 g/L) than in blood culture-negative calves (3...
Milk from 172 commercial cows with mild to moderate clinical mastitis was tested with five antibi... more Milk from 172 commercial cows with mild to moderate clinical mastitis was tested with five antibiotic residue detection assay systems. One hundred cows were treated with one of two intramammary beta-lactam antibiotics, and the remaining 72 cows were treated with intramuscular oxytocin. Milk samples were collected pretreatment, twice after therapy, and again 21 d following the initiation of treatment. Presumptive false-positive assay results were tabulated from all pretreatment and 21-d milk samples and from samples collected following oxytocin therapy. The percentage of false-positive results was 43.6, 37.7, 81.7, 2.6, and 18.8% for the CITE probe (beta-lactam), Delvotest-P, Charm Farm, LacTek (beta-lactam), and Bacillus stearothermophilus var. calidolactis disk assay, respectively. In four of the assay systems, average SCC were significantly higher in samples yielding false-positive results than in those with negative results. Specificity and sensitivity were estimated for each ass...
The efficacy of a dried colostrum powder, DCW Concentrate, as a colostrum supplement or substitut... more The efficacy of a dried colostrum powder, DCW Concentrate, as a colostrum supplement or substitute was tested using four groups of 15 calves. Physical condition and IgG status were examined during the first 30 d of life. Calves were fed the dried colostrum powder (group A), pooled colostrum (group C), or both (groups B and D) 2 h after birth. Calves fed 85 g of the dried colostrum powder dissolved in 3 kg of whole milk (group A) had significantly lower IgG concentrations 24 h after birth than calves of the other groups. Administration of 85 g of the dried colostrum powder plus 3 kg of colostrum (group C) did not lead to significantly higher IgG concentrations 24 h after birth than did administration of 3 kg of colostrum alone (group B). Calves fed 85 g of the dried colostrum powder plus 1.5 kg of colostrum (group D) had an IgG concentration at 24 h of age that was not significantly different from that of calves given 3 kg of colostrum (group B). Morbidity and mortality rates were no...
The 10-point Milk and Dairy Beef Quality Assurance Program was developed collaboratively by the N... more The 10-point Milk and Dairy Beef Quality Assurance Program was developed collaboratively by the National Milk Producers Federation and the American Veterinary Medical Association and is designed to promote and document the responsible use of antibiotics in the dairy industry. One area of emphasis in this program is testing of individual animals for antibiotic residues after a specified post-treatment withdrawal time. We examined the performance of various assay systems on milk samples from individual cows. These assays are used at present on bulk tank milk samples by regulatory agencies, processing plants, producers, and veterinarians to detect the presence of beta-lactam antibiotics. A high proportion of false-positive results was obtained for both the pretreatment milk samples from cows with clinical mastitis and the milk samples obtained 21 days after initial therapy (nonantibiotic and antibiotic) for the treatment of mastitis. A high proportion of false-positive outcomes was obt...
This paper presents the report of a committee of the American Association of Bovine Practitioners... more This paper presents the report of a committee of the American Association of Bovine Practitioners recommending methods for calculating several basic indices of reproductive performance on dairy farms. Indices for several major analytic areas are presented: overall reproductive performance, estrus detection intensity, conception efficiency, pregnancy losses, reproductive culling, and also reproductive efficiency in herds using a bull.
This paper presents the report of a committee of the American Association CALCULATING REPRODUCTIV... more This paper presents the report of a committee of the American Association CALCULATING REPRODUCTIVE INDICES 79 of Bovine Practitioners recommending methods for calculating several basic indices of reproductive performance on dairy farms. Indices presented are: overall reproductive performance, intensity of estrus detection, conception efficiency, pregnancy losses. reproductive culling, and reproductive efficiency in herds using a bull. Data from a hypothetical dairy herd are provided and example indices are calculated.
The Canadian veterinary journal. La revue vétérinaire canadienne, 1997
The objectives of this study were to estimate the prevalence of bacteremia in critically ill, neo... more The objectives of this study were to estimate the prevalence of bacteremia in critically ill, neonatal calves with severe diarrhea or depression, and to describe the variety of bacteria involved. Two studies were conducted in the summers of 1991 and 1993 involving 190 neonatal calves, 1-day to 19-days-old. Bacteremia was detected by blood culture in 31% (28/90) of calves in study 1, and in 24% (19/79) of ill calves and 0% (0/21) of control calves in study 2. Bacteria cultured from blood included Escherichia coli (51% of all isolates), other gram-negative enterics (25.5%), gram-negative anaerobes (5.9%), gram-positive cocci (11.8%), and gram-positive rods (5.9%). Among clinically ill calves, the average age was significantly lower in the blood culture-negative group (5.5 d) than in the blood culture-positive group (7.5 d) (P = 0.004). Mean serum IgG concentration was significantly (P = 0.0001) lower in blood culture-positive calves (1.146 g/L) than in blood culture-negative calves (3...
ABSTRACTObjective. To compare four different dry cow treatments (DCT) and establish their effecti... more ABSTRACTObjective. To compare four different dry cow treatments (DCT) and establish their effectiveness in reducing intramammary infections (IIM). Materials and methods. DCTs included systemic tylosin (12g) alone or accompanied by cefapirine intramammary infusions and or an internal teat sealant. A total number of 278 cows at the end of lactation period were randomly assigned to one of 4 dry cow treatment groups: CESE Group (n=89), intramammary cephapirin and teat sealant. TYCESE Group (n=84), intramammary cephapirin, tylosin 12 g intramuscular and teat sealant. TYSE Group (n=86), 12 g intramuscular tylosin and teat sealant; TY Group (n=76) 12 g intramuscular tylosin only. Milk samples for culture were collected at dry-off and 1 and 2 weeks after calving. Somatic cell counts (SCC) were taken from Dairy Herd Improvement Association (DHI) tests at dry-off, and the first two test days after calving. Results. Bacteria cure rate for Gram-positive intramammary infections (IMI) for TYCESE ...
Animal health research reviews / Conference of Research Workers in Animal Diseases, 2014
The primary source of data on bovine respiratory disease (BRD) prevalence in US adult dairy cattl... more The primary source of data on bovine respiratory disease (BRD) prevalence in US adult dairy cattle is producer surveys, which estimate that 2.4-2.9% of cattle are affected. This estimate appears low when compared to calculations based on limited data regarding on-farm deaths due to BRD and the number of carcasses at slaughter with severe BRD. These calculations indicate that approximately 3% of dairy cows die on farm or go to slaughter with severe BRD. Not included in these data are cows that are treated for BRD and retained. The primary manifestation of BRD on dairy farms is in calves. Nationwide surveys have estimated that 12.4-16.4% of preweaned dairy heifer calves are affected with BRD, and 5.9-11% of calves are affected after weaning. More detailed prevalence studies have generally included a limited number of small farms, with limited calf age range studied. All studies relied on producer diagnosis. Prevalence in these studies ranged from 0 to 52%, with many cases occurring be...
The Canadian veterinary journal. La revue vétérinaire canadienne, 1997
In human, equine, and bovine neonates, early diagnosis of bacteremia remains a challenge for the ... more In human, equine, and bovine neonates, early diagnosis of bacteremia remains a challenge for the internist. The objective of this study was to develop a predictive model for risk of bacteremia, based on a clinical evaluation system called the clinical sepsis score. Blood from 90 ill calves, 1- to 14-days-old from a calf-raising farm in the San Joaquin Valley of California was cultured. The calves were also scored according to a clinical score for hydration status, fecal appearance, general attitude, appearance of scleral vessels, and umbilical abnormality. Age, rectal temperature, heart rate, respiratory rate, and presence or absence of a focal site of infection were recorded. Prevalence of bacteremia was 31% (28/90). A logistic regression model indicated that high clinical score, presence of a focal infection, and increased age were associated with an increased risk of bacteremia in ill calves (P < 0.06). Calves for which the model predicted bacteremia with a probability > or...
Journal of the American Veterinary Medical Association, Jan 15, 1977
In a fecal examination survey (1975-1976) of 217 cats from laboratory colonies, a humane society ... more In a fecal examination survey (1975-1976) of 217 cats from laboratory colonies, a humane society shelter, and homes in east central Illinois, Toxocara mystax eggs were found in 32%, Toxascaris leonina eggs in 6%, Ancylostoma eggs in 9%, Capillaria eggs in 4%, Isospora felis oocysts in 23%, Isospora rivolta oocysts in 24%, and Toxoplasma or Besnoitia oocysts in 1%. The laboratory and humane shelter cats were the most heavily infected. Isospora felis and I rivolta could not be transmitted to 2 pups by feeding oocysts from the cat or to 2 other pups by feeding the organs of mice that had been fed the oocysts.
For three California dairy herds with bulk tank SCC &amp;amp;lt; 200,000/ml, twice daily milk... more For three California dairy herds with bulk tank SCC &amp;amp;lt; 200,000/ml, twice daily milking, and no mastitis vaccine, 254 quarters with mild clinical mastitis were randomly assigned to three groups. Group A (n = 74) was treated with 62.5 mg of intramammary amoxicillin every 12 h for three milkings. Group C (n = 75) was treated with 200 mg of intramammary cephapirin every 12 h for two milkings. Group O (n = 105) was treated with 100 units of intramuscular oxytocin every 12 h for two or three milkings. Aseptic pretreatment quarter samples revealed 94 (37%) coliforms, 65 (26%) environmental streptococci, 34 (13%) other bacteria, and 61 (24%) with no isolate on bovine blood agar plates. Contagious pathogens were not isolated. Clinical cure (return of quarter and milk to normal) and bacterial cure (absence of primary pathogen isolated pretreatment) were assessed at milking 8 and d 20 after initial treatment. No difference existed in clinical (67.6, 67.7, or 66.7%) or bacterial (43.9, 55.0 or 49.1%) cure rate among groups. Clinical cure rates did not differ when quarters were grouped by etiology, but clinical cure rates for quarters with pathogens other than streptococci or coliforms were lower in group O.
For two large California dairy herds with twice daily milking, 171 infected quarters of lactating... more For two large California dairy herds with twice daily milking, 171 infected quarters of lactating cows with mild clinical mastitis were randomly assigned to one of three treatment groups. Group A (50 cows) was treated with 62.5 mg of intramammary amoxicillin every 12 h for three milkings. Group C (50 cows) was treated with 200 mg of intramammary cephapirin every 12 h for two milkings. Group 0 (71 cows) was treated with 100 U of intramuscular oxytocin every 12 h for three milkings. Clinical cure rates did not differ among treatment groups. The cost per episode of clinical mastitis was higher ($54.47) for group C than for groups A ($38.53) or 0 ($34.88). Group 0 had a higher incidence of relapse (41%), and a greater percentage of group 0 cows (65%) experienced an additional mastitic event in the enrolled lactation than did cows in groups A and C. Treatment had no effect on the mean number of nonsalable milkings (24.7) associated with mastitis in the lactation interval subsequent to enrollment on the trial. Twenty-two percent of the cows accrued more than 30 nonsalable milkings and produced 55% of the total nonsalable milkings associated with mastitis. There was no treatment effect on total milk
This paper presents the report of a committee of the American Association CALCULATING REPRODUCTIV... more This paper presents the report of a committee of the American Association CALCULATING REPRODUCTIVE INDICES 79 of Bovine Practitioners recommending methods for calculating several basic indices of reproductive performance on dairy farms. Indices presented are: overall reproductive performance, intensity of estrus detection, conception efficiency, pregnancy losses. reproductive culling, and reproductive efficiency in herds using a bull. Data from a hypothetical dairy herd are provided and example indices are calculated.
Journal of the American Veterinary Medical Association, Jan 15, 1992
An epizootic of subclinical and clinical mastitis caused by Serratia marcescens was investigated ... more An epizootic of subclinical and clinical mastitis caused by Serratia marcescens was investigated in a 1,000-cow dairy farm in California. Serratia marcescens was isolated from 13 to 18% of composite milk samples obtained from lactating dairy cows. During monthly milk sampling performed during a 4-month period, S marcescens was isolated from 38.8 to 62.3% of composite milk samples obtained from cows from which S marcescens was previously isolated. Few cows infected with S marcescens had evidence of clinical mastitis. Somatic cell count value was associated with isolation of S marcescens. Cows with somatic cell counts greater than 500,000 were 5.48 times as likely to have intramammary infections with S marcescens, compared with cows with somatic cell count less than or equal to 500,000. Lactation number also was associated with S marcescens intramammary infection. After adjusting for the effect of lactation number, cows with high somatic cell count values were 2.98 times as likely to ...
Feeding a high concentration of cotton seed meal to young calves resulted in death with lesions c... more Feeding a high concentration of cotton seed meal to young calves resulted in death with lesions compatible with gossypol toxicity. Calves were fed two different commercially prepared rations. Free gossypol concentrations in different lots of the 17% protein ration vaned from 250 to 380 ppm, and the 13% protein ration varied from 40 to 240 ppm. Serum sorbitol dehydrogenase elevation was the most consistent clinical pathological finding. The mean serum sorbitol dehydrogenase concentrations for moribund, hospitalized, and clinically healthy calves were 277, 34, and 45 units/liter. The mean for sorbitol dehydrogenase concentration for healthy calves not fed cotton seed meal was 18 units/liter. Gross lesions included severe effusion of a high protein content fluid into the body cavities of most calves, edema of the mesentery, and hepatomegaly. The most consistent histological lesion was severe centrilobular hepatic necrosis. Elevated levels of liver gossypol were demonstrated. The mean liver gossypol concentration for three calves was 4 1.7 Fglg on a wet weight basis.
The Canadian veterinary journal. La revue vétérinaire canadienne, 1997
The objectives of this study were to estimate the prevalence of bacteremia in critically ill, neo... more The objectives of this study were to estimate the prevalence of bacteremia in critically ill, neonatal calves with severe diarrhea or depression, and to describe the variety of bacteria involved. Two studies were conducted in the summers of 1991 and 1993 involving 190 neonatal calves, 1-day to 19-days-old. Bacteremia was detected by blood culture in 31% (28/90) of calves in study 1, and in 24% (19/79) of ill calves and 0% (0/21) of control calves in study 2. Bacteria cultured from blood included Escherichia coli (51% of all isolates), other gram-negative enterics (25.5%), gram-negative anaerobes (5.9%), gram-positive cocci (11.8%), and gram-positive rods (5.9%). Among clinically ill calves, the average age was significantly lower in the blood culture-negative group (5.5 d) than in the blood culture-positive group (7.5 d) (P = 0.004). Mean serum IgG concentration was significantly (P = 0.0001) lower in blood culture-positive calves (1.146 g/L) than in blood culture-negative calves (3...
Milk from 172 commercial cows with mild to moderate clinical mastitis was tested with five antibi... more Milk from 172 commercial cows with mild to moderate clinical mastitis was tested with five antibiotic residue detection assay systems. One hundred cows were treated with one of two intramammary beta-lactam antibiotics, and the remaining 72 cows were treated with intramuscular oxytocin. Milk samples were collected pretreatment, twice after therapy, and again 21 d following the initiation of treatment. Presumptive false-positive assay results were tabulated from all pretreatment and 21-d milk samples and from samples collected following oxytocin therapy. The percentage of false-positive results was 43.6, 37.7, 81.7, 2.6, and 18.8% for the CITE probe (beta-lactam), Delvotest-P, Charm Farm, LacTek (beta-lactam), and Bacillus stearothermophilus var. calidolactis disk assay, respectively. In four of the assay systems, average SCC were significantly higher in samples yielding false-positive results than in those with negative results. Specificity and sensitivity were estimated for each ass...
The efficacy of a dried colostrum powder, DCW Concentrate, as a colostrum supplement or substitut... more The efficacy of a dried colostrum powder, DCW Concentrate, as a colostrum supplement or substitute was tested using four groups of 15 calves. Physical condition and IgG status were examined during the first 30 d of life. Calves were fed the dried colostrum powder (group A), pooled colostrum (group C), or both (groups B and D) 2 h after birth. Calves fed 85 g of the dried colostrum powder dissolved in 3 kg of whole milk (group A) had significantly lower IgG concentrations 24 h after birth than calves of the other groups. Administration of 85 g of the dried colostrum powder plus 3 kg of colostrum (group C) did not lead to significantly higher IgG concentrations 24 h after birth than did administration of 3 kg of colostrum alone (group B). Calves fed 85 g of the dried colostrum powder plus 1.5 kg of colostrum (group D) had an IgG concentration at 24 h of age that was not significantly different from that of calves given 3 kg of colostrum (group B). Morbidity and mortality rates were no...
The 10-point Milk and Dairy Beef Quality Assurance Program was developed collaboratively by the N... more The 10-point Milk and Dairy Beef Quality Assurance Program was developed collaboratively by the National Milk Producers Federation and the American Veterinary Medical Association and is designed to promote and document the responsible use of antibiotics in the dairy industry. One area of emphasis in this program is testing of individual animals for antibiotic residues after a specified post-treatment withdrawal time. We examined the performance of various assay systems on milk samples from individual cows. These assays are used at present on bulk tank milk samples by regulatory agencies, processing plants, producers, and veterinarians to detect the presence of beta-lactam antibiotics. A high proportion of false-positive results was obtained for both the pretreatment milk samples from cows with clinical mastitis and the milk samples obtained 21 days after initial therapy (nonantibiotic and antibiotic) for the treatment of mastitis. A high proportion of false-positive outcomes was obt...
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Papers by Walt Guterbock