Young Veal Calves Research Articles

Effects of pre-transport diet, transport duration and transport condition on immune cell subsets, haptoglobin, cortisol and bilirubin in young veal calves.

The aim of this study was to investigate effects of pre-transport diets, transport durations and transport conditions on immune cell subsets, haptoglobin, cortisol and bilirubin of young calves upon arrival at the veal farm. An experiment was conducted with a 2 × 2 × 2 factorial arrangement with 3 factors: 1) provision of rearing milk or electrolytes at the collection center (CC); 2) transport duration (6 or 18 hours) and 3) transport condition (open truck or conditioned truck). Holstein-Friesian and cross-bred calves were used (N = 368; 18 ± 4 days; 45.3 ± 3.3 kg). Blood samples were collected from calves (N = 128) at the collection center, immediately post-transport (T0) and 4, 24, 48 hours, week 1, 3 and 5 post-transport. Blood was analyzed for cortisol, bilirubin, haptoglobin, IgG and IgM. Moreover, cell counts of neutrophils, lymphocytes, monocytes, basophils and eosinophils were measured in blood samples taken at the collection center and T0. In these same blood samples, different lymphocyte populations were characterized by flow cytometry, including CD14+ cells, NK cells, δγ+ T cells, CD8+ cells, CD4+ cells and CD21+ cells. Calves transported in the conditioned truck had higher amounts of white blood cell count (WBC) (Δ = 1.39 × 109/l; P = 0.01), monocytes (Δ = 0.21 × 109/l; P = 0.04), neutrophils (Δ = 0.93 × 109/l; P = 0.003), than calves transported in the open truck regardless, of pre-transport diet or transport duration. The study showed that transport condition and duration influenced parts of the innate immune system of young veal calves. Cortisol, bilirubin and WBC seemed to be connected by similar underlying mechanisms in relation to transport conditions. However, it is unclear which specific pathways in the immune system of young calves are affected by different transport conditions (e.g. temperature, humidity, draught).

Transport of Young Veal Calves: Effects of Pre-transport Diet, Transport Duration and Type of Vehicle on Health, Behavior, Use of Medicines, and Slaughter Characteristics

The aim of this study was to investigate effects of different early life transport-related factors on health, behavior, use of medicines and slaughter characteristics of veal calves. An experiment was conducted with a 2 × 2 × 2 factorial arrangement with 3 factors: (1) provision of rearing milk or electrolytes before transport, (2) transport duration (6 or 18 h), and (3) type of vehicle (open truck or conditioned truck). The study included male Holstein-Friesian and cross-bred calves (N = 368; 18 ± 4 days; 45.3 ± 3.3 kg). Data on health status of calves were collected at the collection center and at the veal farm until week 27 post-transport. Behavior of calves was recorded during transport and at the veal farm until week 13 post-transport. Use of herd and individual medical treatments was recorded at the veal farm. The prevalence of loose or liquid manure at the veal farm from day 1 until week 3 post-transport was lower in electrolyte-fed calves transported in the conditioned truck compared to electrolytes-fed calves transported in the open truck or milk-fed calves transported in both the conditioned and open truck (Δ = 11% on average; P = 0.02). In comparison with the open truck, calves transported in the conditioned truck had lower prevalence of navel inflammation in the first 3 weeks post-transport (Δ = 3 %; P = 0.05). More milk-fed calves received individual antibiotic treatments compared to electrolyte-fed calves at the veal farm (P = 0.05). In conclusion, the transport-related factors examined in the present study affected health and behavior of calves in the short-term, but there was no evidence for long-term effects. It remains unknown why no long-term effects were found in this study. Perhaps this absence of transport-related effects was due to multiple use of medical treatments in the first weeks at the veal farm. Alternatively, it might be that the collective effects of the transition from the dairy farm to the veal farm, and of the husbandry conditions during the subsequent rearing period, on the adaptive capacity of calves were so large that effects of individual transport-related factors were overruled.

Effects of pretransport diet, transport duration, and type of vehicle on physiological status of young veal calves

This study aimed to investigate effects of pretransport diet (rearing milk vs. electrolytes), type of vehicle (open vs. conditioned truck), and transport duration (6 vs. 18 h) on physiological status of young calves upon arrival at the veal farm. A total of 368 calves were transported in 2 consecutive batches from a collection center to a veal farm. Blood samples were collected from calves before transport; immediately posttransport (T0); and 4, 24, and 48 h, and 1, 3, and 5 wk posttransport. Blood was analyzed for glucose, urea, lactate, nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHB), creatine kinase, albumin, total protein, osmolality, calcium, sodium, magnesium, and hematological variables. Body weight, rectal temperature, and skin elasticity were determined before and immediately posttransport. Blood glucose, NEFA, and urea concentrations at T0 showed an interaction between pretransport diet and transport duration. Milk-fed and electrolyte-fed calves transported for 18 h did not significantly differ in plasma glucose concentration or serum NEFA concentrations. However, after 6 h of transport, milk-fed calves had higher plasma glucose and lower serum NEFA concentrations (4.71 mmol/L and 586.5 µmol/L, respectively) than electrolyte-fed calves (3.56 mmol/L and 916 µmol/L, respectively). After 18 h of transport, milk-fed calves had lower urea concentrations (5.40 mmol/L) than electrolyte-fed calves (7.38 mmol/L). In addition, at T0, after 6 h of transport, milk-fed calves gained weight (Δ = 0.41 kg), whereas electrolyte-fed calves lost weight (Δ = -0.16 kg). After 18 h of transport, both milk-fed and electrolyte-fed calves showed body weight losses (Δ = -0.67 and -0.74 kg, respectively). Type of vehicle had a limited influence on blood parameters. Concentrations of NEFA and BHB reached the maximum values at T0 and then decreased until wk 5 posttransport. The increase in NEFA and BHB concentrations between prior to and just posttransport (T0) was less pronounced in calves transported for 6 h (746.1 µmol/L and 0.38 mmol/L, respectively) than in calves transported for 18 h (850.6 µmol/L and 0.50 mmol/L). Overall, the recovery rate of calves at the veal farm seemed rapid; all blood parameters returned to (below) pretransport values within 48 h posttransport. We concluded that feeding milk before short-term transport helps young veal calves cope with transport, whereas this is not the case during long-term transport.

DNA microarray assay and real-time PCR as useful tools for studying the respiratory tract Mycoplasma populations in young dairy calves.

With more than 120 species, the genus Mycoplasma is one of the largest taxa in the class Mollicutes, a group of micro-organisms that are characterized by apparent simplicity and to which important animal pathogens belong. Mycoplasmabovis is the most frequently identified pathogenic Mycoplasma in cattle; however, the prevalence of other Mycoplasma species living in calves' airways is poorly understood. The aim of this work was to characterize the respiratory tract mycoplasma populations in calves on one of the largest dairy farms in Italy using a real-time PCR assay and a DNA microarray assay. A total of 49 nasal swabs and 49 trans-tracheal aspirations from non-vaccinated veal calves were analysed. Genomic DNA was extracted from the samples and then tested using a real-time PCR targeting the oppD gene of M. bovis and a DNA microarray that was able to identify more than 70 Mycoplasma species. Forty-two out of 49 calves tested positive for Mycoplasma spp. (85.7 %). None of the samples tested positive for M. bovis. A majority (73.5 %) of the 98 samples tested positive for M. dispar, while 8 samples tested positive for M. bovirhinis (8.2 %). Our results expand our knowledge regarding the diversity of Mycoplasma populations in the respiratory airways of very young veal calves and add data regarding M. bovis prevalence in the Italian cattle population. However, the importance of these species in the respiratory diseases of calves still remains to be determined.

Effects of Supplementing Concentrates Differing in Carbohydrate Composition in Veal Calf Diets: I. Animal Performance and Rumen Fermentation Characteristics

The aim of this experiment was to examine the effects of concentrates in feed, differing in carbohydrate source, on the growth performance and rumen fermentation characteristics of veal calves. For this purpose, 160 Holstein Friesian×Dutch Friesian crossbred male calves were used in a complete randomized block design with a 5×2 factorial arrangement. Dietary treatments consisted of 1) milk replacer control, 2) pectin-based concentrate, 3) neutral detergent fiber-based concentrate, 4) starch-based concentrate, and 5) mixed concentrate (equal amounts of concentrates of treatments 2, 3, and 4). Concentrate diets were provided as pellets in addition to a commercial milk replacer. Calves were euthanized either at the end of 8 or 12wk of age. The overall dry matter intake of the concentrate diets varied between 0.37 and 0.52kg/d. Among the concentrate diets, the dry matter intake was lower in the starch diet (0.37kg/d of dry matter) and differed between the NDF and pectin diets. The average daily gain for all the dietary treatments varied between 0.70 and 0.78kg/d. The mixed- and NDF-fed calves had an increased average daily gain (0.78 and 0.77kg/d, respectively) compared with the starch- and pectin-fed calves (0.70 and 0.71kg/d, respectively). Rumen fermentation in the calves fed concentrates was characterized by a low pH (4.9 to 5.2), volatile fatty acid concentrations between 100 and 121 mmol/L, and high concentrations of reducing sugars (33 to 66 g/kg of dry matter). The volatile fatty acid concentrations of calves fed concentrates were higher than those of the control calves. All concentrate treatments showed a low acetate-to-propionate ratio in rumen fluid (between 1.3 and 1.9). Among the concentrates, the NDF diet had the highest (55.5%) and starch the lowest (45.5%) molar proportions of acetate. Calves fed the mixed, pectin, and starch diets had significantly higher molar proportions of butyrate (13.1 to 15.8%) than the NDF- and control-fed groups (9.9 and 9.6%, respectively). Calves fed the control diet had a higher lactate concentration (21 mmol/L) than the concentrate-fed calves (between 5 and 11 mmol/L). With the exception of the NDF diet, polysaccharide-degrading enzyme activities in the rumen contents generally showed an adaptation of the microorganisms to the carbohydrate source in the diet. The mixed diet exhibited the least variation in rumen polysaccharide-degrading enzyme activities among the enzymes systems tested. Results indicated that the carbohydrate source can influence intake, growth rate, and rumen fermentation in young veal calves.

Nitrite/Nitrate responses to endotoxin in calves.

Plasma concentrations and urinary excretions of nitrite plus nitrate (NOx) increase in heifers after endotoxin-induced nitric oxide synthase activation. The rise can be enhanced by administration of arginine, the substrate for the production of nitric oxide, whose effects may be modified by the iron status. In 10-week-old veal calves (six Simmental x Red Holstein) arginine (0.5 g/kg body weight for 6 h) was intravenously infused. At 2 h after the start of the infusions Escherichia coli endotoxin O26:B6 (2 microg/kg body weight) was intravenously injected. This caused a rise of rectal temperature, heart rate, respiration rate, and of urinary NOx excretion, but not of plasma NOx concentrations, in contrast to the experience with older cattle to which the same amounts of arginine were infused before and during endotoxin administration. In 8-week-old veal calves (18 Simmental x Red Holstein) the question of whether oral supplementation with arginine and iron modifies NOx responses to endotoxin (2 microg/kg) was also investigated. The calves were divided between three groups (GrA-, GirA+, GrC) and before endotoxin injections GrA- was fed 0.5 g arginine/kg for 4 days, GrA+ was fed 0.5 g arginine/kg for 4 days plus 80 mg iron/kg milk for 2 weeks, whereas GrC was not supplemented with arginine or iron. Iron supplementation increased plasma iron concentrations and arginine supplementation increased plasma arginine and urea concentrations and urinary urea excretion. Ensuing administration of endotoxin enhanced plasma tumour necrosis factor-alpha concentrations, rectal temperature, heart rate, and respiration rate, but not plasma NOx concentrations in GrC and GrA- and only transiently and slightly increased plasma NOx concentrations in GrA+ but did not affect urinary NOx excretions. In conclusion, the expected stimulation of NOx responses to endotoxin by intravenous arginine infusion appears to be much weaker in young veal calves than in older cattle. The NOx responses in young veal calves were not modified if arginine was orally administered and plasma NOx were barely enhanced by combined oral supplementation of arginine and iron.

Bovisalm TM and Bovisalm D Vaccines are Safe and Prevent Salmonellosis in Calves

Bovine salmonellosis is an important zoonotic infection1. Serious outbreaks of clinical disease may occur in cattle of all ages and result in devastating economic loss. The most important serotypes which cause disease in calves are Salmonella typhimurium and Salmonella dublin. Both serotypes can cause fever, anorexia, depression, bacteremia, diarrhoea and death.
 Live and dead vaccines have been used to prevent salmonellosis in calves. It is generally believed that cell mediated immunity is necessary to provide longterm protection against salmonellosis. For this reason live attenuated strains have been used because these strains elicit a stronger cell mediated immunity than killed vaccines. Furthermore orally delivered vaccines cause a mucosal immunity, which is important for protection against enteric pathogens.
 A number of different types of live vaccines have been developed. Auxotrophic mutants are dependent on metabolites not, or insufficiently present in the vaccinated animal. Recently, a Salmonella typhimurium strain was described which is auxotrophic for histidine and adenine and which also shows a high sensitivity to tensides2. Furthermore Salmonella dublin strain was described which is auxotrophic for thiamine and adenine. These strains have been used for the development of Bovisalm TM (S. typhimurium) and Bovisalm D (S. dublin); lyophilized vaccines for oral immunization of young veal calves to prevent salmonellosis. In this report we present data to show that these strains are safe and effective in preventing salmonellosis in calves.

A study of iron metabolism in young veal calves by means of ferrokinetics

ZusammenfassungFerrokinetische Untersuchungen des Eisenstoffwechsels bei jungen MastkälbernBei drei fünf Wochen alten Mastkälbern, eins mit einem deutlichen Eisenmangel und zwei nahezu normalen Kälbern wurden einige ferrokinetische Untersuchungen durchgeführt. Es ergab sich, daß die Halbwertszeit der Verschwindensrate für Plasma‐Eisen bei den zwei nahezu normalen Kälbern 53 und 61 Minuten betrug, und bei dem Kalb mit dem klaren Eisenmangel 24 Minuten. Der Eiseneinbau in die Eryhtrozyten war in allen drei Kälbern gleich. Der Höchstwert des Eiseneinbaus in die Erythrozyten lag bei 92% (Tag 7) beim Kalb mit deutlichem Eisenmangel und 91% (Tag 7 und 9) bei den zwei anderen Kälbern. Es wurde festgestellt, daß der Eiseneinbau in die Erythrozyten sehr hoch war, ungeachtet der Menge an Eisen in der täglichen Ration. Dies läßt auf ein hohes Bedürfnis an Eisen für die Bildung roter Blutkörperchen bei allen drei Kälbern schließen. Ferrokinetische Untersuchungen sind brauchbar zur Intensivierung der Kenntnisse des Eisenstoffwechsels bei jungen Mastkälbern.

Residues in Young Veal Calves After Consumption of Milk Containing Penicillin

Residues in urine, kidney, and muscle following consumption of milk containing procaine penicillin G were determined in 4-to 8-day-old Holstein bull calves. Calves were fed milk diluted 1:1 with water. Nine control calves received diluted milk only while 8 calves received diluted milk containing 6,600 IU penicillin/kg (low group), and 10 calves received 13,200 lU/kg of milk consumed (high group). Urine samples were collected over 11h after each morning feeding for 3 days. Calves were slaughtered on day 4 of trial and kidney, muscle, and urine samples obtained. Urine was tested for residues with the Live Animal Swab Test and tissues by the Swab Test on Premises. Both tests are microbiological assays used for detecting growth inhibition of Bacillus subtilis. No residues were detected in urine of control calves. Residues in urine were detected in 6 calves in the low group and 7 calves in the high group after feeding. At slaughter, residues were in 3 of 5 urine samples from calves in the low group and 8 of 10 calves in the high group. However, no residues were detected in kidney or muscle of control or treated calves.