The epidemiology of the "collapse syndrome" in suckled calves.

Cases of a diarrhoeic syndrome characterised by acute collapse were seen in single-suckled beef calves on hill farms during a three year period. The association between the occurrence of this syndrome, which we have termed the "collapse syndrome", and various epidemiological parameters, is investigated and discussed.     

哺乳犊牛的消化特点与蛋白质需要

本文从犊牛的消化生理特点出发,综述了犊牛出生后的生理特征及蛋白质、必需氨基酸的需要量,并对代乳品中蛋白质原料进行了论述。     

Biochemical studies of the "collapse syndrome" in suckled calves.

A total of 351 single-suckled beef calves were blood sampled at twice-weekly intervals for the first two and a half weeks of life. Twenty three of them died, 13 of a syndrome characterised by acute collapse and 10 of diarrhoea which had persisted for several days before death. Those which died acutely showed a sudden terminal rise in blood levels of potassium, magnesium, inorganic phosphate and total protein. Those which died after several days of diarrhoea showed a more gradual increase in blood chloride and urea concentrations and in packed cell volume values. It is suggested that these changes indicate a difference in the pathogenesis of the two situations. Calves which died had lower blood glucose levels before the onset of clinical signs than those which survived. It is suggested that this may have been a contributory factor in their mortality.     

Immune globulin studies of the "collapse syndrome" in suckled calves.

A total of 351 single suckled beef calves were blood sampled during the first three days of life and thereafter twice weekly until five samples had been obtained. Eighty four calves suffered from diarrhoea and 23 of these died. No relationship could be found between the total circulating immune globulin level of a calf and its subsequent fate, suggesting that the syndrome with which many calves were affected is different in character from other forms of neonatal bovine diarrhoea.     

Immunoglobulin transfer and weight gains in suckled beef calves force-fed stored colostrum.

Concentrations of immunoglobulins and total proteins in second-day post-partum serum samples of 62 beef calves from multiparous dams were measured by zinc sulphate turbidity, electrophoresis, radial immunodiffusion and refractometry. These results, together with health records and weight gains, were used to evaluate the practice of routinely force-feeding 1 L of stored colostrum to suckled beef calves immediately after birth. There was no apparent benefit from such force-feeding. It did not result in greater 48-hour serum immunoglobulin levels, nor did it improve weight gains at 42 days. None of the calves required treatment for neonatal disease, but one force-fed calf died from inhalation of regurgitated colostrum.     

Ascorbic acid levels in the bronchopneumonia of calves]

The level of ascorbic acid in the blood plasma of 59 calves was determined. The age of the calves ranged between two and three months and the samples of blood were collected in January. The first group of calves included 30 animals displaying no clinical symptoms of disease: the average ascorbic acid level was 0.50 +/- 0.18 mg per 100 ml. In the second group, consisting of 19 calves, the blood of the animals was collected three weeks after the termination of the acute stage of bronchopneumonia; the average value of ascorbic acid was 0.30 +/- 0.14 mg per 100 ml. The lowest average value of ascorbic acid was obtained in the calves at an acute stage of bronchopneumonia, reaching 0.18 +/- 0.11 mg per 100 ml. The differences of results between groups I and II and between groups I and III were found to be statistically significant. A conspicuous drop of ascorbic acid level was ascertained in calves suffering from bronchopneumonia-this problem needs deeper scrutiny, owing to the fact that bronchopneumonia is responsible for considerable economic losses in large-capacity calf houses.     

An epidemiological study of gammaglobulin levels in newborn calves

The effect of various factors on serum gammaglobulin concentration in newborn dairy calves was studied in 181 calves on six commercial farms. The refractometer test for monitoring colostrum management was found to be a reliable, rapid and practical method up to 6 days after birth. The three factors, time of first colostrum feeding, quantity of first colostrum intake and gammaglobulin concentration in first colostrum, explained 19.9% of the variation in serum gammaglobulin concentration. Time of milking, time of first colostrum intake and gammaglobulin concentration in first colostrum explained 21.0% of the variation in serum gammaglobulin concentration. Calves from first lactation cows showed lower serum gammaglobulin concentration than calves of older cows.     

Behavior of artificially suckled foals

Artificial feeding of foals is rarely practiced other than for raising orphans. This study investigated the effects of an artificial feeding system on the growth and welfare of a group of “Cavallo Agricolo Italiano da Tiro Pesante Rapido” foals (n = 12). A viable artificial rearing method could allow for the commercial supply of mare’s milk for cosmetic or pediatric purposes. Six foals were maintained on an artificial suckling (AS) regimen using a modified bovine milk replacer, and 6 remained with their dams (control group, naturally suckled [NS]).Housing and management was identical for both groups. During the 6-month trial, the foals were weighed every 3 weeks from 4 days of age, and their daily weight gains were calculated. Foals were directly observed for 6 separate 24-hour periods at 4, 10, 47, 114, 142, and 176 days of age, and an ethogram was compiled from the observed behaviors (resting, social, alimentary, and eliminative).All data were analyzed using a repeated measures analysis.At 4 days of age, the behavior of the AS foals was significantly different from that of the control group foals in that they stood up for longer duration (530 vs. 174 minutes, P < 0.01), performed fewer suckling bouts (P < 0.01), and did not play (P < 0.01) or lick (P < 0.05). AS foals were more aggressive and cross-suckled more (P < 0.01) at 10 days of age than at the first observation period.After weaning, AS foals ate more concentrate and less hay than the control group foals (P < 0.01). However, at the end of the trial, there were no significant differences between the groups in terms of weight (AS vs. NS [mean ± standard deviation]: 350 ± 15 vs. 360 ± 20 kg, P = 0.34) and daily weight gains (1630 ± 370 vs. 1600 ± 310 g/d, P = 0.88).Artificial suckling techniques could be applied to Cavallo Agricolo Italiano da Tiro Pesante Rapido foals, without negative effects on growth and welfare during the first 6 months of life. In fact, after an initial adaptation period, the AS foals did not exhibit any abnormal behavior or behavioral differences compared with NS foals. Further studies are required to improve this rearing technique, which could facilitate the efficient raising of orphan foals and/or marketing equine milk. Additional research would enable the effects of this rearing technique on the long-term growth, behavior, and health of the foals.     

Dynamics of changes in thyroxine levels in castrated newborn calves]

Changes in thyroxin levels were studied in calves castrated just after birth. The changes in thyroxin concentration in the blood serum were studied until the eighth day of life of the calves and the weight gains were monitored until weaning at an age of 90 days. In the experimental group, lower thyroxin levels were first recorded in the third hour post natum and were observed to persist until the eighth day; except for three hours the decrease was not statistically significant. Neither were any significant differences observed in the average daily gains in both groups of calves. Treatments like non-surgical castration in newborn calves do not elicit extreme stress reactions that would be conducive to disorders of health and vitality.     

Hormonal interrelationships in postpartum suckled dairy cows.

Three cross-bred cows calved in March and April and were followed until day 62 after parturition. Each animal was suckled by 2 calves ad libitum. All calves were removed from the cows on day 55 after parturition. Blood was collected 3 times per day from the jugular vein by venipuncture. On 4 occasions after parturition--i.e. days 7-8, 21-22, 35-36 and 49-50, the cows were bled through a jugular venous catheter every 30 min during the 24 h. The plasma samples were analyzed for the content of 15-keto-13,14-dihydro-PGF2 alpha (main PGF2 alpha metabolite), LH, prolactin, cortisol and progesterone by radioimmunoassay methods. The concentration of PGF2 alpha increased from 280 to 730 pmol/l within the last 4 days before parturition. The highest geometric mean was 3106 pmol/l on the day of parturition. Thereafter a steady decrease of PGF2 alpha metabolite concentration was seen until day 21 when it reached plateau at 148 pmol/l. In all cows plasma LH concentrations increased significantly (P < 0.05) from about 1.6 micrograms/l on days 7-8 to 2.4 micrograms/l on days 21-22 post partum. The frequency of LH pulses showed no tendency to increase as the postpartum period progressed and averaged 6.5 pulses/24 h. Mean plasma LH concentrations increased from 2.1 micrograms/l 2 days before weaning to 3.2 micrograms/l 2 days after weaning (P < 0.05). LH peaks occurred less frequently in association with prolactin and cortisol peaks than in their absence. A partial positive correlation between PGF2 alpha metabolite and cortisol (r = 0.30) was found on days 7-8 post partum. Correlation between prolactin and cortisol on days 7-8 and 21-22 post partum was also positive (r = 0.20 and r = 0.27, respectively). There was a negative correlation between LH and cortisol on days 7-8 (r = -0.27) and days 49-50 (r = -0.21) post partum. The first and short progesterone increase observed after weaning was terminated in conjunction with PGF2 alpha metabolite peaks.