Investigation of the effects of transport and lairage on hydration state and resting behaviour of calves for export.

Plasma sodium concentrations, packed cell volume, total plasma protein concentration and dermal skinfold thickness were used to assess the state of hydration of 113 transported calves before and after lairage and in 30 control calves on the farm of origin. Skin thickness increased significantly (P less than 0.05) and total protein increased slightly during transport and decreased during lairage. These changes suggest that transport may cause dehydration and lairage may help in recovery. Plasma potassium concentration decreased during transport, but the effect was inversely related to the distance travelled, and the concentration increased during lairage. These changes are consistent with recovery from initially high cortisol levels at loading. The resting behaviour of 150 transported calves was recorded hourly for six hours. More time was spent resting and sleeping by the transported calves than has been reported for non-transported calves and more still by small transported calves, suggesting that transport is exhausting, that lairage helps recovery and that small calves are more adversely affected. During lairage the numbers of calves asleep decreased to values reported for normal calves, suggesting that 10 hours lairage was adequate. However, small calves did not return to their normal rest patterns within the observation period.     

Influence of feeding different amounts of first colostrum on metabolic, endocrine, and health status and on growth performance in neonatal calves

Colostrum intake is important for health and postnatal development of neonatal calves. We studied the effects of enhanced first colostrum feeding on growth, health status, and metabolic and endocrine traits in calves during their 1st wk of life. Calves of group CL (GrCL; n = 7) were fed colostrum of milkings 1 to 6 twice daily during the first 3 d of life, followed by milk replacer (MR) up to d 7. Calves of group CH (GrCH; n = 7) were fed colostrum of the first milking during the first 3 d and then colostrum (of the first milking) twice daily, which on d 4, 5, 6, and 7 was diluted with 25, 50, 75, and 75 parts of MR, respectively. Pre- and postprandial blood samples were taken on d 1, 2, 3, and 7 for the determination of various metabolic and endocrine traits, and on d 5 intestinal absorption capacity was measured using the xylose absorption test. Rectal temperatures and fecal scores were higher (P < .05) in GrCH than in GrCL. Plasma concentrations of total protein and albumin were higher (P < .05) on d 7, IgG on d 2 and 3, and urea on d 2, 3, and 7 in GrCH than in GrCL. Plasma concentrations of triglycerides were higher (P < .05) on d 2 and of phospholipids and cholesterol were higher (P < .01) on d 7 in GrCH than in GrCL. Plasma insulin and glucagon concentrations were higher (P < .05) in GrCH than in GrCL, whereas prolactin and growth hormone concentrations were higher (P < .05) in GrCL than in GrCH. Enhanced colostrum intake had no effects on xylose absorption on d 5. Higher plasma protein, urea, and lipid concentrations in GrCH partly mirrored higher protein and fat intake but additionally pointed to higher protein synthesis and lipid turnover.     

Respiratory, renal, hematologic, and serum biochemical effects of hypertonic saline solution in endotoxemic calves

The respiratory, renal, hematologic, and serum biochemical effects of hypertonic saline solution (HSS) treatment were examined in 12 endotoxic, pentobarbital-anesthetized calves (8 to 20 days old). Escherichia coli endotoxin (055:B5) was infused IV at a rate of 0.1 microgram/kg of body weight over 30 minutes. Endotoxin induced severe respiratory effects, with marked hypoxemia and increases in arterial-alveolar O2 gradient (P[A-a]O2), physiologic shunt fraction (Qs/Qt), and physiologic dead space to tidal volume ratio (Vd/Vt). Oxygen consumption was decreased, despite an increase in the systemic O2 extraction ratio. Peak effects were observed at the end of endotoxin infusion. The renal response to endotoxemia was characterized by a decrease in free-water reabsorption and osmotic clearance, as well as a decrease in sodium and phosphorus excretion. Endotoxemia induced leukopenia, thrombocytopenia, hyperphosphatemia, hypoglycemia, acidemia, and increased serum alkaline phosphatase concentrations. Calves were treated with HSS (2,400 mosm/L of NaCl, 4 ml/kg, n = 4) or an equivalent sodium load of isotonic saline solution (ISS; 300 mosm/L of NaCl, 32 ml/kg, n = 4 90 minutes after the end of endotoxin administration. Both solutions were infused over a 4- to 6-minute period. A control group (n = 4) was not treated. Infusion of HSS or ISS failed to induce a significant change in Pao2, P(A-a)O2, (Qs/Qt), (Vd/Vt), or oxygen consumption. Both solutions increased systemic oxygen delivery to above pre-endotoxin values. Hypertonic saline infusion induced significant (P less than 0.05) increases in serum Na and Cl concentrations and osmolality, whereas ISS induced a significant increase in serum Cl concentration and a significant decrease in serum phosphorus concentration.(ABSTRACT TRUNCATED AT 250 WORDS)     

Histamine H1, H2 receptor effects on mechanics of ventilation and gas exchange in neonatal calves

The effect of histamine infusion (IV) on pulmonary mechanical and gas exchange properties of healthy neonatal Holstein-Friesian calves was determined. Histamine increased pulmonary resistance and static pressure-volume hysteresis and decreased dynamic compliance, but failed to change static compliance; changes were compatible with constriction of both large and small airways without a change in lung elasticity. Histamine decreased arterial oxygen tension by increasing the alveolar-arterial oxygen difference, probably because ventilation-perfusion inequalities resulted from small airway constriction. The pulmonary mechanical and gas exchange effects of histamine were prevented by pretreatment with the H1 receptor antagonist, tripelennamine, but not with the H2 receptor antagonist, metiamide. The histamine-induced changes in static pressure-volume hysteresis and dynamic compliance were reversed by sighing, and histamine effects on the lung were eliminated by 15 minutes after cessation of histamine infusion.     

Plasma leptin status in young calves: effects of pre-term birth, age, glucocorticoid status, suckling, and feeding with an automatic feeder or by bucket

Plasma leptin concentrations depend on energy intake and fat stores and are modified by hormones, such as glucocorticoids. We have measured plasma leptin concentrations in pre-term calves (born on day 277 of gestation) during the first week of life, in full-term calves (290 days of gestation), fed similar amounts of nutrients with colostrum or a milk-derived formula, combined with or without dexamethasone treatment (to simulate a high glucocorticoid status), during the first five days of life, and in calves fed with an automatic feeder or by bucket or suckling on dams up to day 28. Leptin concentrations increased (P<0.05) from birth to day 7 in pre-term calves. In full-term calves leptin concentrations were stable from day 1 to day 4 in colostrum-fed animals, but decreased (P<0.05) and were lower (P<0.05) if fed a formula with similar amounts of energy and macronutrients as colostrum. Concentrations increased (P<0.05) from day 1 to day 2 in calves suckling on dams and then remained elevated, but did not change and were lower in calves fed with the automatic feeder or by bucket than in suckling calves. Dexamethasone only slightly elevated leptin concentrations. There was no episodic secretion pattern, and there were no consistent associations of leptin with various metabolites and hormones. In conclusion, plasma leptin in young calves with respect to effects of nutrition (low energy intake) and hormones (glucocorticoids) and in association with metabolic changes behaved differently from what is known in mature cattle.     

Pharmacokinetics and cardiovascular effects following a single oral administration of a nonaqueous pimobendan solution in healthy dogs

Pimobendan is an inodilator used in the treatment of canine congestive heart failure (CHF). The aim of this study was to investigate the pharmacokinetics and cardiovascular effects of a nonaqueous oral solution of pimobendan using a single‐dose, operator‐blinded, parallel‐dose study design. Eight healthy dogs were divided into two treatment groups consisting of water (negative control) and pimobendan solution. Plasma samples and noninvasive measures of cardiovascular function were obtained over a 24‐h period following dosing. Pimobendan and its active metabolite were quantified using an ultra‐high‐performance liquid chromatography–mass spectrometer (UHPLC‐MS) assay. The oral pimobendan solution was rapidly absorbed [time taken to reach maximum concentration (T_max) 1.1 h] and readily converted to the active metabolite (metabolite T_max 1.3 h). The elimination half‐life was short for both pimobendan and its active metabolite (0.9 and 1.6 h, respectively). Maximal cardiovascular effects occurred at 2–4 h after a single oral dose, with measurable effects occurring primarily in echocardiographic indices of systolic function. Significant effects persisted for <8 h. The pimobendan nonaqueous oral solution was well tolerated by study dogs.     

Effect of varying carbohydrate and fat content of milk replacer on body composition of Holstein bull calves

The objective of this study was to determine the effect of varying concentrations of dietary fat and carbohydrate on changes in body composition of Holstein bull calves fed under isocaloric and isonitrogenous intake conditions. Thirty-two calves were assigned to a randomized block design with three dietary treatments, eight calves per treatment, and one baseline group of eight calves. Animals were reared from birth to 85 kg live BW (SEM = 0.57). All calves began treatments between 2 and 6 d of age. Three different milk replacer treatment diets were designed to deliver 14.8 (low fat, LF), 21.6 (medium fat, MF), or 30.6% of DM (high fat, HF) fat; 55.3, 46.7, or 35.4% of DM lactose; and 23.5, 24.8, or 27.0% of DM CP, respectively. Gross energy values were 4.62, 5.09, and 5.77 Mcal/kg for the LF, MF, and HF milk replacers, respectively. From d 1 to 14, calves were offered 0.24 Mcal intake energy/kg BW(0.75), adjusted weekly based on increases in BW, and 0.28 Mcal intake energy/kg BW(0.75) from d 15 to slaughter. Dry feed was not offered. Dry matter, energy, CP, and fat intakes were 55.2 kg, 257.6 Mcal, 13.0 kg, and 8.2 kg; 52.8 kg, 268.8 Mcal, 13.1 kg, and 11.4 kg; and 46.8 kg, 270.3 Mcal, 12.6 kg, and 14.3 kg for the LF, MF and HF treatments, respectively. Energy and CP intakes did not differ among treatments (P = 0.63 and 0.79, respectively). Fat and DMI were different among treatments (P = 0.001 and 0.02, respectively). Empty BW gains were 0.61, 0.61, and 0.65 kg/d for LF, MF, and HF, respectively, and were not different among treatments (P = 0.27). Empty body CP, water, and ash gain were not different among treatments (P = 0.65, 0.99, and 0.57, respectively). Empty body retained energy and fat gain were 27.2 and 57.7% greater for calves fed the HF than for those fed the LF diet (P = 0.06 and 0.006, respectively). Fat as a percentage of the whole empty body on a water-free basis was lower for calves consuming the LF diet (28.6%) than for those fed the HF diet (34.6%), whereas percentage of CP on an empty body, water-free basis was greater for calves consuming the LF diet (59.2%) than for those fed the HF diet (54.9%) (P = 0.006). The results of this study demonstrated that, under isocaloric and isonitrogenous intake conditions, equivalent dietary energy from fat compared to carbohydrate, above 15% fat, has no beneficial purpose unless additional fat deposition is required in the animal. Further, the data demonstrate significant changes in body composition independent of growth rate.     

Comparison of biochemical parameters in the blood of healthy and diseased calves in a large barn

In a high-capacity calf-house, twenty-one calves were subjected to repeated clinical and biochemical examination until they were 22 weeks old. For evaluating the health condition of the animals, the calves were divided into two groups, one including healthy animals and the other including those suffering from bronchopneumonia and diarrhoea as the most frequent disorders in high-capacity calf-houses. From four to eight weeks of age, both groups of calves showed low levels of plasma magnesium and iron. The levels of plasma zinc and copper showed a continuous decrease with age. Compared with the healthy calves, the animals affected by a disease had statistically significantly lower levels of plasma vitamins (A, E, C). Further, the diseased animals also showed statistically significantly decreased levels of plasma glucose, serum albumins, and a lower activity of alkaline phosphatase in plasma. In addition to this, the diseased animals also had significantly higher levels of plasma gamma-globulins and urea. These clinico-biochemical parameters can be used for determining the subclinical forms of disease, for objective diagnosis and for the introduction of preventive measures in high-capacity calf-house.     

Comparison of two oral electrolyte solutions and route of administration on the abomasal emptying rate of Holstein-Friesian calves

Dehydrated calves with diarrhea are routinely given an oral electrolyte solution (OES) by suckling or esophageal intubation. An important issue related to rehydration therapy is the rate of OES delivery to the small intestine. It is widely assumed that the glucose content of the OES does not impact the speed of resuscitation and that fluid administered by esophageal intubation provides a similar resuscitative response to that obtained by suckling. The aims of this study were to compare the abomasal emptying rate in calves suckling an OES containing a high or low glucose concentration and in calves administered a high-glucose OES by suckling or esophageal intubation. Seven male Holstein-Friesian calves were given the following treatments in random order: 2 L of a commercially available high-glucose OES ([glucose] = 405 mM) by suckling or esophageal intubation or 2 L of a commercially available low-glucose OES ([glucose] = 56 mM) by suckling. Abomasal emptying rate was determined by acetaminophen absorption, ultrasonography, and glucose absorption. High-glucose OES rapidly increased plasma glucose concentration after suckling but produced a slower rate of abomasal emptying than did low-glucose OES. Esophageal intubation of high-glucose OES produced the same initial change in abomasal volume as did suckling, but delayed the rate of OES delivery to the small intestine. Our results suggest that suckling a low-glucose OES provides the fastest rate of abomasal emptying and plasma volume expansion, whereas a high-glucose OES provides the most appropriate oral solution for treating hypoglycemic calves.     

The effects of experimentally induced bronchopneumonia on the pharmacokinetics and tissue depletion of gentamicin in healthy and pneumonic calves

The effects of a bovine bronchopneumonia model on the pharmacokinetics and tissue residue depletion profiles of gentamicin in calves weighing 90-140 kg was explored. Two groups of heifer calves were used. The first was a normal group, while the second group had bronchopneumonia induced. A scoring system was developed to evaluate the extent of disease in the groups. A bimodal distribution of the serum pharmacokinetic parameters in the pneumonic group was caused by the effects of dehydration. When the severely dehydrated calves were omitted from the analysis, serum clearance of gentamicin was significantly higher in the pneumonic group than in the normal group (P less than 0.05). The pharmacokinetic equations used to fit the tissue concentrations varied from tissue to tissue and between groups. Because the best equation of a particular tissue's concentrations varied between groups, withdrawal periods, which are normally determined in healthy animals, may be inappropriate in diseased animals. Addition of several parameters (serum creatinine, serum urea nitrogen, albumin, fibrinogen, and total protein concentrations, white blood cell counts, central fluid volume, volume of distribution at steady state, area under the serum concentration vs time curve, serum clearance, and elimination rate constant) to these tissue-depletion models using multiple regression improved the prediction of a concentration in a given tissue.     

Evaluation of the optimal strong ion difference concentration of an oral electrolyte and buffering solution for the treatment of neonatal calf diarrhea

An observational study was conducted to comparatively assess the efficacy of three different oral rehydration and buffering solutions, differentiated by their strong ion difference (SID) concentration, for treatment of neonatal calves with naturally acquired diarrhea. The SID concentrations tested were 100 mM, 170 mM and 230 mM for treatments SID₁₀₀, SID₁₇₀ and SID₂₃₀, respectively. Clinical assessment and blood gas analysis were completed for 18 diarrheic calves once pre- and twice post- (6 and 24 hr after) oral administration with one of the three treatments. A repeated measure mixed model approach was used to analyze (a) the within-group efficacy of each treatment over time and (b) the between-group comparison at each timepoint. SID₂₃₀ treatment resulted in a significant increase in blood pH, HCO₃⁻, BE, SID and Na⁺ at 6 and 24 hr after treatment, and a significant decrease in AG and K⁺ by 24 hr after treatment. There were no significant changes in any of the blood gas parameters after treatment with SID₁₀₀ and SID₁₇₀. SID₂₃₀ treatment also resulted in blood gas parameter changes that were significantly different to the other two groups. These results suggest that the optimum SID concentration for the treatment of calves with diarrhea is likely to be higher than current recommendations.     

The effects of cold stress on neonatal calves. I. Clinical condition and pathological lesions.

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.     

Elemental composition, water, and total lipid content in peripheral nerves, spinal cord and brain of healthy adult dogs

Peripheral nerves, spinal cord, and brain of healthy adult dogs were analysed biochemically for sodium, potassium, calcium, magnesium, copper, zinc, iron, aluminium, silicon, total chloride, total tissue water and total lipid content. Flame atomic absorption spectrophotometry was used for elemental quantitation of the hydrochloric acid tissue extracts. Cerebrum and spinal cord had similar values for all parameters measured. Total sodium values were higher in nerves compared to central nervous system (CNS) (brain and spinal cord), while respective values for potassium were lower. Tissue levels of calcium, iron and silicon were comparable in brain, spinal cord and nerves. However, magnesium concentrations were two to three times higher in CNS than in nerves; and the reverse was true for aluminium levels. Tissue concentrations of zinc and copper were marginally higher in CNS than in nerves.