The effects of colostrum consumption and feed restriction during marketing and transportation of male dairy beef calves: Impact on pre-transport nutritional status and on farm recovery.

The aim of this study was to evaluate the effects of colostrum consumption and feed restriction on biomarkers of stress, nutritional and health status, gut functionality, and behavior in male dairy beef calves being marketed and transported. A total of 82 male Holstein calves (42 ± 1.2 kg of body weight and 14 ± 0.9 d of age) were used to study the amount of colostrum given at birth at the dairy farm of origin, the degree of feed restriction suffered at an assembly center simulation (d -4 to d -1), and the effects of a 19 h transportation (d -1). Treatments were as follows: control calves (CTRL; n = 16) were fed 10 L of colostrum at the dairy farm of origin, milk replacer (MR) and concentrate at the assembly center, and were not transported; calves fed high colostrum and milk replacer (HCMR; n = 17) were given 10 L of colostrum at the dairy farm of origin, MR at the assembly center, and transported; calved fed high colostrum and rehydrating solution (HCRS; n = 16) were given 10 L of colostrum at the dairy farm of origin, a rehydrating solution (RS) at the assembly center, and transported; calves fed low colostrum and milk replacer (LCMR; n = 17) were given 2 L of colostrum at the dairy farm of origin, MR at the assembly center, and transported; and calves fed low colostrum and rehydrating solution (LCRS; n = 16) were given 2 L of colostrum at the dairy farm of origin, RS at the assembly center, and transported. Transported calves mimic a 19-h transportation. After transport, all calves were fed 2.5 L of MR twice daily and had ad libitum access to concentrate, straw, and water. Calves' recovery was followed for 7 d. Concentrate intake and health records were collected daily from d -4 until d 7 and body weight (BW) and blood samples were collected on d -4, -1, 0, 1, 2, and 7 of the study. Results showed that the feeding regimen provided at the assembly center reduced BW for the HCRS and LCRS calves compared with the CTRL, HCMR, and LCMR calves. Concentrate intake peaked on d 0 in the transported calves, followed by a reduction of intake on d 1 after transportation. Concentrate intake recovery was lower for the LCRS and LCMR calves. On d -1, nonesterified fatty acids and ß-hydroxybutyrate concentrations were greater for the HCRS and LCRS calves compared with the CTRL, HCMR, and HCRS calves. After transportation, serum Cr-EDTA concentration was greater for the HCRS and LCRS calves than the HCMR, LCMR, and CTRL calves. The LCRS calves had the lowest serum concentration of citrulline. Finally, health scores were greater for the LCRS calves from d 0 to 7. In summary, both the greatest degree of feed restriction during the assembly center and the low colostrum consumption at birth negatively affected the recovery of concentrate consumption and BW, gut functionality, health status, and behavior in calves after arrival at the rearing farm.

Effects of vanadate and insulin on glucose 1,6-P2 and fructose 2,6-P2 levels in rat skeletal muscle.

Levels of glucose 1,6-P2 but not fructose 2,6-P2 were found decreased in skeletal muscle of alloxan-diabetic ketotic rats. Administration of both insulin and vanadate restored the altered values without affecting fructose 2,6-P2 concentrations. In normal rats, insulin increased muscle levels of both sugars, and vanadate decreased glucose 1,6-P2 without changing fructose 2,6-P2 levels. Enzymatic activities involved in glucose 1,6-P2 and fructose 2,6-P2 metabolism were not affected under any experimental condition.

Effect of vanadate on the glucose-1,6-bisphosphate synthase and glucose-1,6-bisphosphatase activities of phosphoglucomutase.

Phosphoglucomutase, in addition to catalyzing the interconversion of glucose 1-P and glucose 6-P, catalyzes both the synthesis of glucose 1,6-P2 from glucose monophosphate and either fructose 1,6-P2 or glycerate 1,3-P2, and the hydrolysis of glucose 1,6-P2. Vanadate inhibits the mutase activity, activates the synthase activities, and does not affect the phosphatase activity. These effects suggest that the "exchange" step postulated for the phosphoglucomutase pathway is specifically inhibited by vanadate.

A method for determination of glucose 1,6-bisphosphatase.

A sensitive and specific method to measure glucose 1,6-bisphosphatase activity, which allows the identification of the reaction products is described. [U-14 C]Glucose 1,6-P2, synthesized by the glucose 1-P kinase activity of phosphofructokinase, is used as substrate. The reaction products are separated and identified by chromatography on ion-exchange paper.

Glucose 1,6-bisphosphate and fructose 2,6-bisphosphate levels in different types of rat skeletal muscle.

1. The concentration of glycogen, glucose 1,6-P2, fructose 2,6-P2 and the content of glycogen phosphorylase, phosphofructokinase, 6-phosphofructo 2-kinase and glucose 1,6-P2 phosphatase activity, have been determined in rat muscles which differ in their fiber composition: extensor digitorum longus, gastrocnemius, diaphragm and soleus. 2. Glucose 1,6-P2 concentration seems to be related to the glycolytic capacity of the muscle, while fructose 2,6-P2 concentration does not. 3. No significant relationship exists between the fiber type and the content in glucose 1,6-P2 phosphatase and 6-phosphofructo 2-kinase activities.

Partial purification and characterization of an aldohexose 1-P phosphatase from pig skeletal muscle.

An enzyme with a molecular weight of 54,000 which possesses phosphatase activity acting on glucose 1-P, galactose 1-P and mannose 1-P has been partially purified and characterized from pig skeletal muscle. The enzyme is free of phosphoglucomutase and galactokinase activities, and it possesses a neutral optimum pH. Pi acts as an inhibitor; glucose, galactose and mannose do not produce any effect. Divalent cations are required for activity, Mg2+ being the most effective activator. Micromolar levels of fluoride and millimolar levels of chloride act as inhibitors; however, vanadate does not produce any effect. The enzyme may have an important role when galactose accumulates in tissues; for example, in galactosemic patients and in young animals ingesting high-galactose diets.

Changes in glucose 1,6-bisphosphate content in rat skeletal muscle during contraction.

Glucose 1,6-bisphosphate, fructose 2,6-bisphosphate, glycogen, lactate and other glycolytic metabolites were measured in rat gastrocnemius muscle, which was electrically stimulated in situ via the sciatic nerve. Both the frequency and the duration of stimulation were varied to obtain different rates of glycolysis. There was no apparent relationship between fructose 2,6-bisphosphate content and lactate accumulation in contracting muscle. In contrast, glucose 1,6-bisphosphate content increased with lactate concentration during contraction. It is suggested that the increase in glucose 1,6-bisphosphate could play a role in phosphofructokinase stimulation and in the activation of the glycolytic flux during muscle contraction.