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Feeding practices, ration composition, and body condition scores (BCS) were assessed in an observational case-contrast study of Norwegian dairy herds with low (n = 98) and high (n = 94) mastitis infection rates. Differences between the 2 groups of herds were associated with feeding practices and amount of roughage. More herds in the low-infection group were fed a reduced amount of roughage at drying off, and reduced rations during the dry period resulted in lower BCS at calving. Cows in the low-infection herds had significantly lower BCS in the last month before calving and the first month of lactation than cows in the high-infection herds. The significant associations between mastitis infection rates and BCS, frequency of concentrate feeding, and amount of roughage at drying off and during the dry period indicated that feeding practices may have an important influence on the risk of mastitis in Norwegian dairy cows.

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Due to extreme weather conditions, a flock of outwintered Icelandic horses had to manage for several days on snow as the source of free water. They were fed grass silage ad lib, and any change in feed consumption was not observed. After nine days, blood samples were taken and analysed for plasma osmolality, they were subjected to a simple clinical examination, and offered drinking water. Osmolality levels were within normal limits and mean value did not differ significantly from samples which previously were taken of the same individuals. The general condition of the horses was normal, with no signs of clinical dehydration or disease. The horses showed very little interest for the offered drinking water. This suggests that in cold winter weather, horses being fed grass silage and adjusted to eat snow, can manage for several days with snow substituting liquid water without their physiology and welfare being challenged.

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Data from the Norwegian dairy herd recording system were used to evaluate herd level criteria for good and poor udder health in dairy cows. All dairy herds with at least 10 cow-years were included (n = 12,780). The association between bulk milk somatic cell count (BMSCC) and clinical mastitis rate (CM) was weak (R2 = 0.002), indicating that studies based on BMSCC provide different information regarding udder health than studies based on CM. The strongest correlations were found between average cow milk somatic cell count (CMSCC) and BMSCC and between percentage of individual cow milk sample >200,000 cells/mL and the variables BMSCC and CMSCC. A new variable called new infection rate (NEWINF) based on individual cow somatic cell count measurements and CM was evaluated. The NEWINF is influenced by the frequency of individual cow milk samplings, and, to compare herds, it is necessary to adjust for the frequency of cow milk samplings on each farm. The NEWINF was found to be a useful tool for describing overall udder health status at the farm level, as it combines both CM and somatic cell count.

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Fifty-nine of the 65 dairy farms with cubicle sheds in the Norwegian county of Oppland in 1990 were included in a study of rearing accommodation, cubicle refusal and mastitis incidence. The farmers recorded the favoured resting location of the individual cows and heifers throughout the final week of pregnancy as well as during calving. The observations were matched with individual records of mastitis cases during the first 30 days after calving. Mastitis incidence in the heifers was analysed by logistic regression using rearing accommodation and cubicle refusal as independent variables, controlling for herd as a clustering factor. Cubicle refusal was found in 29% of the heifers, but in only 3% of older cows. The results of the analysis indicated a tendency for cubicle refusal to be associated with an increased mastitis incidence among the heifers (OR = 2.2, c.i.95%OR = 0.9-5.4, P = 0.08). Cubicle refusal accounted for 21% (0-32%) of the mastitis cases in the study population (PAF = 0.21).

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Sixty of the 65 dairy farms with cubicle houses in the Norwegian county of Oppland were included in a field study of the management of calving in 1990. The farmers recorded the location of the cow when giving birth, farmer presence and whether assistance was given during calving, occurrence of suckling, and time after birth when cow and calf were separated. Such data were recorded for a total of 1125 calvings. About 10% occurred on pasture, while 78% of the remaining calvings took place in the cubicle-equipped section. Thirteen percent calved in a calving pen, the remaining cows being tethered at the time of calving. Thirty-two percent of the calvings took place in houses lacking a calving pen altogether. Farmers were present during 41% of the calvings. Suckling most frequently occurred after pasture calvings, and was least frequent after calvings within the cubicle-equipped section of the cowhouse. Injuries to the calf caused by trampling or contact with fittings etc. were rare, and no more common in association with calving in the cubicle-equipped section than with calving taking place with the cow isolated from the rest of the herd. All calves were removed from their dams within 24 h after birth.

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The relationship of an increase in fowl cholera outbreaks in turkeys with an increase in environmental temperatures during June, July, August, and September between 1959 and 1992 was analyzed. High environmental temperatures were found to be influential in the development of fowl cholera in turkeys. When the average monthly maximum environmental temperatures for 5 mo of July and 7 mo of August during the 13 yr between 1967 and 1979 were above 30.5 C, there was a significantly (P < 0.05) higher number of fowl cholera outbreaks in turkeys for each month than during the same months when the average maximum temperatures were below 30.5 C. To test the hypothesis that an increase in fowl cholera outbreaks was preceded by an increase in temperature, the pre- and postoutbreak temperatures for 46 selected outbreak clusters occurring between 1959 and 1992 were averaged. Both the average maximum and minimum temperatures for the latter 9 days of the preoutbreak period were highly significantly (P < 0.001) higher than those of the average cluster outbreak day and the following four postoutbreak days. Also, for the nine individual days of the latter pre-outbreak period, the daily average maximum temperature was significantly (P < 0.05) higher for 3 days and partially significantly (P < 0.10) higher for 3 days than that of the average cluster outbreak day, and the daily average minimum temperature was significantly (P < 0.05) higher for 2 days and partially significantly (P < 0.10) higher for 1 day than that for the average cluster outbreak day.

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Milk yield and milk acetoacetate (M-acac) were measured weekly for the first 6 weeks of lactation in 5 herds with a ketosis problem. Ketosis treatments and the corresponding ketotest score, were also recorded. The treatment rate was highest 7-16 days after calving. Most of these early cases were associated with low ketone levels in milk, whereas the treatment rate for cows with high ketone levels was highest 17-31 days after calving. Nearly half of the treated cows were low-ketone animals. They were classified as ketosis cases in the cow health card records, although probably suffering from other post partum disturbances in many instances. About 40% of the cows with high ketone levels recovered spontaneously. Reduction in milk yield associated with peak M-acac levels was transient and moderate. It was concluded that health card statistics overestimates the severity of the ketosis problem in Norway.

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Serum IgG was used to evaluate the immune status of calves up to 180 days of age in 300 Norwegian dairy herds. Several factors were found to significantly affect the levels. Among these were geographical district, season, and factors related to housing and feeding.

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Turkeys were hauled in a truck and exposed to Pasteurella multocida in the drinking water. The clinical course of fowl cholera was modified in hauled turkeys as compared to unhauled turkeys by delaying the onset of depression and reducing the severity of the disease. In unhauled turkeys, there was a marked increase in mortality in the first experiment and a marked increase in depression at the end of the second experiment. In both experiments average cloacal temperature was higher during the first 5 days after inoculation in unhauled than in hauled turkeys. On the day after hauling, plasma corticosterone concentration decreased in both hauled and unhauled turkeys.

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Of a total of 16 turkeys in a temperature controlled chamber with a low air velocity, 14 died during an accidental 16-hr exposure, because of a malfunction of a thermostat, to a temperature of 38.5 C and 80% relative humidity. These turkeys had been previously maintained at a temperature of 20 C for 6 days. Of the 2 surviving turkeys, one alert and one depressed, there were 1) an increased percent erythrocytes in the hematocrit, 2) a decreased ratio of blood mononuclear cells to blood polymorphonuclear cells, 3) a marked increase in plasma corticosterone concentration, and 4) a definite reduction of lymphocytes in the bursal follicles of the alert turkey and a nearly complete depletion in the depressed turkey.

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In three incidents, uninoculated turkeys separated from Pasteurella multocida-inoculated turkeys died of fowl cholera; it was inferred that the pathogen was transmitted by aerosol through the circulating air. Uninoculated and inoculated turkeys were separated by a solid partition and wire netting, and were handled separately. Turkeys were inoculated with a highly virulent strain of P. multocida, which induced the pulmonary form of fowl cholera. In four of the five uninoculated turkeys that died, pneumonia was the principal lesion. In two of these turkeys, which were bled one day before death while still alert, the plasma corticosterone concentration had increased markedly.

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Turkeys inoculated with Pasteurella multocida either in the palatine air spaces or via drinking water were maintained t high (33.4-37.4 C), low (2.6-5.3 C), and moderate (19.8-22.4 C) temperatures in temperature-controlled chambers to determine the influence environmental temperature had on the pathogenesis of fowl cholera. In inoculated turkeys maintained at high temperatures, there was a delay in the onset of depression and, in most instances, in mortality in relation to those at low or moderate temperatures. In turkeys inoculated via drinking water and maintained at low temperatures, there was a higher mortality than in those at high or moderate temperatures. In turkeys maintained at low temperatures during the preinoculation period, the onset of depression was accelerated more after inoculation than in those maintained at moderate temperatures before inoculation. The percentage of leukocytes in the hematocrit was higher in turkeys inoculated int he palatine air spaces and maintained at low temperatures than in turkeys similarly inoculated but maintained at high or moderate temperatures. Cloacal temperatures were higher in all inoculated turkeys maintained at high temperatures than in those at low or moderate temperatures, and decreased markedly when turkeys became moribund. In turkeys inoculated in the palatine air spaces, deaths from pneumonia occurred more frequently at low temperatures and torticollis occurred more frequently at high temperatures than at the other temperatures.

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The morphologic changes in the adrenals and bursa of Fabricius were evaluated from turkeys inoculated with Pasteurella multocida either in the palatine air spaces or via drinking water and maintained at high (33.4-37.4 C), low (2.6-5.3 C), and moderate (19.8-22.4 C) temperatures in temperature-controlled chambers. There was a slight hyperplasia of the adrenal cortical cells and a hypertrophy of the nuclei in the uninoculated turkeys maintained at both high and low temperatures, but these changes were more marked in turkeys maintained at low temperatures. Regardless of the temperature to which the turkeys were exposed, there was an increase in adrenal weight, hyperplasia of the cortical cells, hypertrophy of the nuclei of the cortical cells, and depletion of lipid in the cortical cells in the turkeys that became depressed after inoculation with P. multocida. In the uninoculated turkeys exposed to high temperatures there was a reduction in the weight of the bursa of Fabricius, atrophy of the follicles, and a reduction in the number of lymphocytes within the follicle, which did not occur in the bursae from uninoculated turkeys maintained at low temperatures. In the turkeys inoculated with P. multocida, there was a marked reduction in bursal weight, atrophy of the follicles, and reduction in the number of lymphocytes within the follicles.

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Radioimmunoassay was used to determine plasma corticosterone concentration (PCC) in turkeys inoculated with Pasteurella multocida via either the palatine air spaces or the drinking water and maintained at high (33.4-37.4 C), low (2.6-5.3 C) and moderate )19.8-22.4 C) temperatures in temperature-controlled chambers. In uninoculated turkeys maintained at high temperatures, the PCC was generally lower than in turkeys maintained at moderate temperatures, whereas the opposite occurred in turkeys maintained at low temperatures. After inoculation with P. multocida, all groups of inoculated turkeys showed an increase in the average PCC, which attained a level in some turkeys of over 40 ng/ml, in relation to the average in the uninoculated turkeys, which ranged from 1.8 to 27.3 ng/ml. This increase was proportional to the severity of the infection that developed. The PCC was found to be a sensitive indicator of an incubating infection of P. multocida, since it was markedly increased in turkeys that were bled one day before the onset of depression. In turkeys that were inoculated via the palatine air spaces and maintained at 20 C, the PCC on the day of inoculation was significantly (P less than 0.05) lower in the turkeys that later died than in those that survived. Generally, the PCC was higher in the turkeys that either died between 5 and 10 days after inoculation or were depressed aa the end of the experiment on day 10, relative to the turkeys that were alert at the end of the experiment.

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A method of determining corticosterone concentration in turkey plasma was developed using radioimmunoassay. Compared to fluorometric analysis and competitive protein-binding radioassay, this method had the following advantages: 1) results were consistent, 2) the method was simple and rapid to perform, 3) only 20 lambda of plasma was required, 4) all procedures were performed using the same tube except for counting, and 5) unknown and standard samples were treated identically. The coefficient of variation with the 5 ng/ml standard sample between 14 sets of assays was 12.6% and the average coefficient of variation within duplicate assays of unknown samples randomly selected from each of the 14 series was 4%. Using this method, there was an increase in the average plasma corticosterone concentration in all groups of inoculated turkeys one day after inoculation of Pasteurella multocida which was significantly (P less than .05) greater than that of the noninoculated groups.

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During the summer of 1975 (from June 30th to July 28th) weekly milk samples were obtained from 49 cows kept on pasture during the daytime, and from 48 cows which were confined indoors in stanchion barns and fed grass twice a day. The cows on pasture were exposed to relatively moderate temperatures, which were somewhat lower than for the indoor group (Table I). In the cows kept on pasture, an increase in the milk somatic cell content (MSCC) was observed throughout the experimental period, whereas no corresponding increase was recorded in the indoor group (Table III). This increase in MSCC appeared to occur primarily in non-infected quarters (Table IV). The data from the present investigation seem to indicate that the seasonal increase in MSCC during the summer, which has been reported by several other investigators, cannot be directly related to environmental temperature per se.

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