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1.
Newborn, male, Holstein calves, were continuously housed for three weeks in calf hutches at 17 degrees C or in a thermal environment which varied rhythmically on a daily basis either between -20 degrees C and -8 degrees C (experiment A) or between -30 degrees C and -18 degrees C (experiment B). Compared to warm-housed calves, cold-housed calves in experiment A had metabolic rates which were significantly higher (p less than 0.001) in a standing position but which were not significantly different (p less than 0.05) in a recumbent position. Recumbent and standing cold-housed calves in experiment B had an increased (p less than 0.05) metabolic rate compared to warm-housed controls. Heat loss was less (p less than 0.05) for recumbent cold-housed calves in experiment B than for standing calves in a thermoneutral environment. Localized subcutaneous hemorrhages of hindlimbs were a consistent necropsy finding among all cold-housed calves. Average daily gains of cold-housed calves were not significantly different from warm-housed controls. Clinical, physiological and pathological findings indicated that cold treatments used in the present study did not cause serious harm to calves. It was concluded that calves housed in properly managed hutches are remarkably cold tolerant.  相似文献   

2.
Twenty calves, heifers of the Holstein-Friesian breed and crossbreds with the Slovak Pied breed, were divided into two groups at the average age of 19 days. The trial group was kept outdoors in wooden hutches and the control group was housed in an insulated building. Blood was sampled at the age of 20, 33, 48 and 60 days at the outdoor temperatures of 3 degrees C, -2 degrees C, -5 degrees C and -8 degrees C. The calves kept in hutches where temperatures were always lower than in the insulated calf-house had the higher level of nonesterified fatty acids in all observations. The largest, highly significant difference was determined at the age of 60 days at the outdoor temperature of -8 degrees C (271 mumol/l vs. 224 mumol/l), and the significance of differences was also observed in the first and third blood samplings at the temperatures of 3 degrees C and -5 degrees C. The differences were highly significant in the first group between the first and fourth, and second and fourth samplings. In the calves kept in the insulated building the difference was significant between the first and fourth observation because the content of free fatty acids was also gradually increasing in this case (Tab. I). Glycaemia values were also higher in the calves kept in hutches (Tab. II). The most noticeable (significant) difference was determined at the age of 48 days at the outdoor temperature of -5 degrees C (4.3 mmol/l vs. 3.9 mmol/l). Significant differences within the group were recorded only in calves from the trial group kept in hutches. Insulin concentrations increased gradually with the older age of animals (Tab. II). At the age of 20 days the values were identical in fact in both groups and the highest concentrations were recorded at the age of 60 days. The differences between the groups were not significant, the largest difference was observed at the end of milk feeding period at the age of 60 days (19 microUI/l in calves from hutches and 15.6 microUI/l in calves from the insulated building). Triiodothyronine concentrations decreased from the starting values of 0.8 nmol/l and 0.76 nmol/l in both groups at the age of 33 days to the values of 0.61 and 0.62 nmol/l.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   

3.
Housing temperature effects on growth, feed utilization and feed digestion of 12, 7-mo-old Standardbred colts were evaluated for 22 wk beginning in late November. Colts were assigned to one of two treatments: housed in a barn heated at 10 degrees C (warm) or housed in a barn with no external heat supply (cold). All horses were allowed outdoors for 4 h daily. Mean temperatures of the warm and cold barn from November to April were 10.9 +/- .66 and -5.2 +/- 1.72 degrees C, respectively. Hair coat weight of cold-housed colts was 1.4- to twofold (P less than .05) that of warm-housed colts from December through April but declined for both groups from fall to spring. All colts were fed a pelleted diet to meet National Research Council (1989) energy guidelines for moderate gain (.65 kg/d). Warm-housed colts gained weight 29% more rapidly (P less than .01) than cold-housed colts (.67 vs .52 kg/d). Skeletal growth, measured by cannon bone circumference, wither and croup height, was not affected by housing temperature. Nutrient digestion by both groups of colts was compared to that of mature, warm-housed ponies. Ponies had longer (P less than .05) digestive tract retention times and higher digestibilities for every nutrient than the young horses did. Although retention times by all colts were similar, cold-housed colts digested more ADF and less phosphorus (P) than did warm-housed colts (P less than .05). Over time, digestibilities of DM, NDF and P declined (P less than .05) for colts but not for ponies. Maintenance energy needs were estimated at 34.6 kcal/kg BW for cold-housed colts vs 26.3 kcal/kg BW for warm-housed colts. Young horses need 1.3% more maintenance energy per Celsius degree decrease in temperature below 0 degree C. To sustain a constant moderate gain, daily DE intake needs to be increased .7% per Celsius degree decrease in ambient temperature below 0 degree C.  相似文献   

4.
Metabolic heat production and rectal temperature were measured in 19 newborn calves (41.8 +/- 3.7 kg) during hypothermia and recovery when four different means of assistance were provided. Hypothermia of 30 degrees C rectal temperature was induced by immersion in 18 degrees C water. Calves were rewarmed in a 20 to 25 degree C air environment where thermal assistance was provided by added thermal insulation or by supplemental heat from infrared lamps. Other calves were rewarmed by immersion in warm water (38 degrees C), with or without a 40-ml drench of 20% ethanol in water. Resting (prehypothermia) and cold-induced summit metabolism of the calves was 2.5 +/- .1 and 8.2 +/- .22 W/kg and occurred at rectal temperatures of 39.5 +/- .06 and 36.2 +/- .26 degrees C, respectively. During cooling, metabolic heat production declined at the rate of .65 W/kg per degrees C decline in rectal temperature. The time required to regain euthermia from a rectal temperature of 30 degrees C was longer for calves with added insulation and those exposed to heat lamps than for the calves in the warm water and warm water plus ethanol treatments (90 and 92 vs 59 and 63 +/- 6.4 min, respectively). During recovery, the calves rewarmed with the added insulation and heat lamps produced more heat metabolically than the calves rewarmed in warm water. Total heat production during recovery was 34.1, 31.1, 18.3, 16.9 +/- 1.07 kJ/kg for the calves with added insulation, exposed to the heat lamps, in warm water and in warm water plus an oral drench of ethanol, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

5.
The aim of the present study was to examine consequences of sudden changes in ambient temperature over a 4-hour period (see part 1 [ELMER & REINHOLD, 2002]) on respiratory health in clinically healthy calves. Therefore, the relationship between short-term changes in ambient temperature and the occurrence of clinical respiratory disease was checked over a period of 3 weeks after exposure in 10 calves exposed to 5 degrees C, in 9 calves exposed to 35 degrees C and in 8 control calves (kept at 18-20 degrees C). Within the period beginning 3 days before exposure and lasting until up to 21 days after exposure, each calf was examined clinically. Rectal temperature and respiratory rate were measured daily. All calves were euthanised on day 21 after exposure. Macroscopically visible pneumonic lesions were evaluated using a semiquantitative system. Tissue samples from tonsils, bronchi, trachea, lung and mediastinal lymph nodes were examined bacteriologically. In contrast to non-exposed control calves, severe respiratory illness was observed in individual calves of both exposed groups (5 degrees C, 35 degrees C). Significant increases in body temperature, respiratory rate and animal losses (2 calves died in the group exposed to 5 degrees C, one calf died in the group exposed to 35 degrees C) were the main clinical findings. At necropsy (3 weeks after exposure), no pneumonic lesions were observed in control calves--despite the fact that this group had the highest microbiological colonisation rates in tonsils and in large airways, i.e. trachea and bronchi, within all groups. However, variable pneumonic lung lesions were seen in remaining calves exposed to cold or warm air (5 degrees C, 35 degrees C). The microbiological examination confirmed that mainly Mycoplasma spp. were identified in the lung tissue of calves exposed to 5 degrees C while Pasteurella multocida and/or Mannheimia haemolytica were the only germs found in the lung tissue of calves exposed to 35 degrees C. The results of parts 1 and 2 of the present study related to health issues of calves should be taken into account for future legislation on animal welfare.  相似文献   

6.
Clinically healthy calves (aged 3-6 weeks) were exposed to defined ambient temperature for 4 hours (cold: 5 degrees C, 60% humidity, n = 12; warm: 35 degrees C, 60% humidity, n = 11). During the exposure of each animal in a climatic chamber, certain parameters of lung function, respiratory mechanics, blood gas analysis, circulation, metabolism and thermal regulation were registered simultaneously in order to study immediate physiological consequences of different environmental conditions. In comparison to control calves (18-20 degrees C, 60% humidity, n = 13) an insufficient adaptation of these young calves was noticed in both cold and warm conditions. At 5 degrees C, marked changes in lung function were observed, i.e. airway constriction, pulmonary hypertension, and ventilation-perfusion-mismatching leading to hypoxemia and hypercapnia. Due to compensation by the circulatory system, a sufficient O2-consumption of the organism as well as an unchanged body temperature were maintained. At 35 degrees C, the respiratory pattern changed to panting and a higher dead space ventilation. No changes were observed in pulmonary gas exchange and blood arterialisation. Due to hyperventilation, the partial pressure for CO2 decreased in blood. Since the body temperature increased continuously, thermal regulation was insufficient. This situation would have led to animals collapsing after a period of heat stress lasting longer than 4 hours. In conclusion, young calves up to the age of 6 weeks were not able to tolerate acute changes in ambient temperature. This was true for cold conditions (5 degrees C) as well as for hot conditions (35 degrees C). The results of this study should be taken into account in order to optimise transport and farming conditions.  相似文献   

7.
A total of 36 calves were used in three experiments to test the efficacy of a potassium thiocyanate extract of Pasteurella haemolytica in protecting against experimental pneumonia. In each of experiments A and B, 12 calves were divided into three equal groups. The first group was vaccinated with an aerosol of a potassium thiocyanate extract twice, two weeks apart; the second group was vaccinated subcutaneously once only with the same extract. The third group of calves in both experiments remained as unvaccinated controls. In experiment C, six calves were vaccinated intramuscularly and six were left as controls. Approximately one month after vaccination all calves were challenged with an aerosol of bovine herpesvirus 1 (isolate 108) followed in 4 d by an aerosol of P. haemolytica type A1 (the same strain from which the potassium thiocyanate extract had been made). Varying degrees of protection against subsequent development of experimental pneumonic pasteurellosis in cattle were seen in vaccinated calves as compared to control calves in these experiments. The results indicate that protection of cattle against pneumonic pasteurellosis may prove possible with a sub-cellular extract of P. haemolytica.  相似文献   

8.
Fifteen three- to six-month old Hereford-cross calves were divided into three groups. The first group was inoculated with bovid herpersvirus 1 (Strain 108), the second with a commercial intranasal vaccine against bovid herpesvirus 1 and the third group acted as controls. At least three weeks after vaccination, all calves were weaned, placed in an environmental chamber at 25.0 degrees C (days) and -13.3 degrees C (nights) and challenged with an aerosol of bovid herpesvirus 1 followed four days later by an aerosol of Pasteurella haemolytica. All surviving calves were sacrificed four days after the second aerosol. None of the calves inoculated with bovid herpesvirus 1 virus or the commercial vaccine developed a generalized pneumonia, although there were one or two nodules (4--8 mm diameter) in two of the calves given the commercial vaccine. Four of the five control calves had extensive lobar pneumonia at necropsy, two of the five died from the disease. Details of the clinical, pathological, bacteriological, virological and some of the serological findings are reported.  相似文献   

9.
The objective of the experiment was to find out the effect of extremely low temperatures on the biochemical characteristics of the cows. Twenty-one dairy cows were used as the experimental material. The experimental group (n = 12) was kept loose in an open barn without thermal insulation and the control group (n = 9) was kept in an insulated cow-house. The winter season included two periods of extremely low temperatures: from the 3rd to the 21st of January 1985 the average minimum temperature in the open barn was -12.6 degrees C and the lowest temperature was -19 degrees C, and in the period from the 8th to the 20th of February 1985 the average minimum temperature was -13.1 degrees C and the lowest recorded temperature was also -19 degrees C. At the beginning of hypothermic stress, the concentration of non-esterified acids and total proteins increased in the cows of the experimental group; potassiaemia was decreased in this group. Cholesterolaemia and glycaemia increased during the long-continued exposure to low temperatures. The activity of the thyroid gland was increased at all measurements.  相似文献   

10.
The effect of ambient temperature and humidity on the structure of respiratory epithelium of calves was studied. Four calves of each of three experiments were acclimatized to a nonoperational environmental chamber for six days and then exposed to constant extremes of temperatures and relative humidity of one of 30 degrees C --35%, or 27 degrees C--92%, or 5 degrees C--92% respectively in this chamber for eight days each. Five calves (3 and 2) were similarly acclimatized then exposed to 1 degrees C--40%. Nasal swabs were taken from all animals at regular intervals. Swabs of three animals yielded Mycoplasma spp. and one swab yielded the virus of infectious bovine rhinotracheitis. Detailed histological studies of respiratory epithelium of nose, trachea, major bronchus and terminal bronchioli were conducted at four sites. Goblet cells were least in calves held in hot and dry air; calves held in dry air had the least polymorphonuclear cells and the greatest prevalence of hypochromatic cell layers and vacuolation of epithelial cells. Differences between experiments were evident most for sites of trachea and major bronchus.  相似文献   

11.
Newborn Holstein-Friesian calves were cold stressed by immersion in water at 15 to 17 degrees C until the core body temperature was lowered by 10 degrees C. Non-cold stressed calves were immersed in water at thermoneutral temperature (35 to 37 degrees C). The time required to lower the core body temperature of the cold stressed calves by 10 degrees C was 172 +/- 87 minutes (mean +/- SD). The time required for the core body temperature of the cold stressed calves to return to normal after immersion was 400 +/- 140 minutes (mean +/- SD). Differences were observed between cold and noncold stressed calves in the shivering response during immersion and the clinical condition after immersion. Cold-induced pathological lesions were confined to tissues located peripherally, particularly in the hind legs. Significant differences were observed between cold and noncold stressed calves in the incidence of subcutaneous edema in the ventral sternum (P less than or equal to 0.025), subcutaneous hemorrhage in the hind legs (P less than or equal to 0.025), synovitis (P less than or equal to 0.025) and hemorrhage (P less than or equal to 0.05) of the synovial membranes of the hock joints and hemorrhage (P less than or equal to 0.05) into the hock joint cavities.  相似文献   

12.
Numbers of airborne bacteria and fungi in calf houses   总被引：1，自引：0，他引：1  
Counts of airborne bacteria colony forming particles (BCFP) and fungi were made at intervals throughout one year in three calf houses using a six stage Andersen Sampler. House 1 was insulated, mechanically ventilated and heated, House 2 was insulated and provided with a controlled natural ventilation system, while House 3 was uninsulated with natural ventilation. Each house contained 36 bought-in bull calves. Every six weeks the 12 oldest calves were removed and replaced by 12 four-week-old calves. The mean count of BCFP was highest in House 2 (101.6 X 10(3) m-3) and lower in House 3 (67.6 X 10(3) m-3). The mean count of aerial fungi was significantly lower in House 3 (40.5 X 10(3) m-3) than in Houses 1 and 2 (119.3 X 10(3) m-3 and 127.1 X 10(3) m-3, respectively). The count of aerial BCFP and fungi showed large seasonal fluctuations, but there was a general trend towards lower counts during the winter period. The mean incidence rate of respiratory disease among the experimental calves was 67.7%. The highest mean incidence rate was recorded in House 2, but differences between houses were not significant. The results are discussed in relation to the environmental requirements for raising of calves, and in the light of the current concept of air hygiene as a major predisposing factor in the web of causation of calf respiratory disease.  相似文献   

13.
Nasopharyngeal swabs were taken from four groups of veal calves at intervals throughout their growth and the aerobic bacteria cultivated from the swabs counted. The calves were kept under three different husbandry systems; naturally ventilated straw-yards, fan-ventilated crates and crates with a controlled climate. The numbers of bacteria isolated varied in a complex manner; however, in one group of calves a significant proportion (P less than 0.01) of the variation in weekly bacterial counts was associated with the changes in vapour pressure and temperature which took place between two and four days previously. In calves kept at a constant temperature of 16 degrees C, the bacterial populations in the nasopharynx were at a minimum between 65 and 75 per cent relative humidity and tended to rise at humidities outside this range. There was a temporal relationship between nasopharyngeal bacteria and lung lesions. In three groups the numbers of bacteria in calves at nine weeks old were positively correlated (P less than 0.05) with lung damage observable at 16 to 18 weeks old.  相似文献   

14.
A Holstein-Friesian bull and three Holstein-Friesian cows were seronegative for bovine viral diarrhea (BVD) virus but were persistently infected with the virus. Virus was isolated from buffy coat cells and nasal and lacrimal secretions during their lifetime, and they remained free of clinical signs of BVD. The three cows were pregnant when purchased, and they gave birth to full-term calves. One calf lived only a few hours, one calf became ill and died within a few days, and one calf became ill and was euthanatized within a few weeks. One cow was then bred and became pregnant but aborted a 7-month fetus. A second cow was bred approximately 5 months after parturition but did not conceive. The third cow was necropsied 6 weeks after calving, because of loss of weight. Although the bull's semen contained BVD virus when seropositive cows were bred, normal calves were born. When seronegative heifers were bred, they became seropositive to BVD virus within two weeks, with higher titers in six weeks. On heifer conceived after one service but aborted a 6-month fetus. Three others continued to have estrous cycles until their titers rose to 1:128, then they conceived and gave birth to normal calves. Another heifer conceived on the first service, had a titer of 1:128 two weeks after breeding, and gave birth to a normal calf.  相似文献   

15.
An outbreak of a disease characterised by very high mortality occurred in a group of nine calves (1B4 months old) in a zero-grazing unit 2-3 weeks after an introduction of an apparently healthy alien sheep into the calf pen. Five of the six calves which contracted the disease died. The main clinical signs observed were marked depression, persistently high body temperature (40,5-41,5 degrees C), copious mucopurulent nasal and ocular discharges, dyspnoea, bilateral keratoconjunctivitis with corneal opacity, enlargement of the superficial lymph nodes and marked erythema and/or superficial erosions of the buccal mucosae. At necropsy there were lesions in the upper respiratory and digestive tracts, lymph nodes, brain, eyes, liver, kidneys and the urinary bladder.The lesions were histopathologically characterized by fibrinoid vasculitis which was accompanied by lymphocytic infiltration in the parenchyma of the affected tissues. Based on the evidence of contact between the calves and the recently introduced foreign sheep, the characteristic clinical signs and histopathological findings, a diagnosis of sheep-associated malignant catarrhal fever was made.  相似文献   

16.
BACKGROUND: Age-related changes in hematologic values are known to occur in many species. Few published studies include repeated measurements of hematologic parameters in calves during the first months of life. OBJECTIVE: The aim of the present study was to monitor hematologic values by sequential measurements from birth to 6 months of age in 15 healthy calves of the Norwegian Red breed, and compare the results to reference intervals for adult, lactating dairy cows. METHODS: Fifteen clinically healthy calves were sampled every week during the first 5 weeks of life and every month thereafter until 6 months of age. Hematologic values were measured using the ADVIA 120 hematology system. Reference intervals were determined for 75 healthy adult cows of the same breed. RESULTS: Compared with adult reference intervals, the MCV was lower and the RBC count was higher in calves throughout the investigation period. Hemoglobin concentration stayed largely within the adult reference interval. Mean MCHC was lower than adult values for 5 weeks, then increased and reached adult values by weeks 10-12. The mean lymphocyte count for calves reached adult reference values at weeks 6-8, and the mean monocyte count increased steadily until weeks 14-16. For most leukocytes, interindividual variation was larger during the first 5-8 weeks of life. The mean platelet count for calves was higher than the adult reference interval until weeks 19-21 of age. CONCLUSIONS: Age-specific reference intervals for calves from birth to 6 month of age are needed for RBC count, MCV, MCHC, red cell distribution width, and platelet and lymphocyte counts.  相似文献   

17.
The parameters of acid-base balance were investigated in relation to the time difference between the blood sampling and the examination and ambient temperature in the field conditions. The transfer of the samples from field conditions to a laboratory was imitated by putting the case with the samples into a thermostat at the temperature of 20 degrees C and 37 degrees C. In the first trial, at the temperature of 20 degrees C, statistically significant changes in pH values were recorded in seven hours. If the temperature in the case was 37 degrees C, the differences in pH, BE, SBi and BB values and in the partial pressure of CO2 were statistically significant in six hours. Applying the above results we state that the acid-base parameters can be examined within five hours after blood sampling supposing that the blood samples are kept at the temperature of 0-4 degrees C and using for veterinary diagnostics the equilibration method after Astrup.  相似文献   

18.
The serological responses of calves at two different ages to a commercial hardjo/pomona vaccine were examined. Microscopic agglutination test (MAT) titres of a group of ten three-month-old calves and three groups of 11,12 and 12 six-month-old calves were monitored over a period of 28 weeks. The calves vaccinated at three months of age had a poorer serological response rate to vaccination (30% responded to pomona and 40% responded to hardjo) compared with those vaccinated at six months of age (91-100% responded to pomona and 83-91% responded to hardjo). Those three-month-old calves which did respond also produced a lower level of-antibody than six-month-old calves. It was concluded that in order to achieve adequate protection using commercially available leptospiral bacterins at the recommended dose, vaccination should not be undertaken routinely with animals less than six months of age. Where circumstances arise in which earlier vaccination is necessary, repeat vaccination for continued protection at six months or older is suggested.  相似文献   

19.
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 less than 1 and 84 days. One group of seven calves was kept in a controlled environmental chamber with air temperature of 5 degrees C and 58% relative humidity (RH) and another group of eight calves was kept at 16 degrees 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 degrees C and 16 degrees C (P greater than 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 less than 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 less than 1, 14, 28, 70 and 84 days of age (P less than 0.001).  相似文献   

20.
Bovine coronavirus isolated from calf faeces diseased with gastroenteritis and passaged to colostrum-free calves agglutinated mouse and rat erythrocytes. The agglutination reaction depended on temperature and took place only at a temperature of 4 degrees C. At a temperature of 37 degrees C the agglutinate broke down within 15 minutes. The coronavirus could be detected by the haemagglutination test in the contents of the small and large intestines and in the faeces of experimentally and naturally infected calves. The agglutination capacity of mouse erythrocytes was not affected by careful fixation of these erythrocytes with formalin and subsequent lyophilization and remained unchanged for as long as 52 weeks of storage at a temperature of 4 degrees C. It was demonstrated by a comparative examination of 182 samples of the faeces of calves suffering from diarrhoea that haemagglutination test was as sensitive as electron microscopy.  相似文献   

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