Acid-base balance in ruminating calves given sodium hydroxide-treated straw

Abstract

1. Studiesofwhole-body balancesof non-metabolizable base(NB)and severalminerals, and of relevant acid-base quantities in blood and urine, were carried out in two 6-month-old ruminating Holstein x Friesian bull calves fed on fixed rations containing 500 g barley straw/kg diet (group A) to examine the quantitatively important components of the balance of NB and determine the rates of mineral and NB retention associated with normal body growth.2. Parallel balance studies were conducted in six other bull calves given fixed rations containing 500 g alkali-treated barley straw/kg diet to evaluate the effects of long-term alkali-straw feeding on the rates of body growth and skeletal mineral and NB deposition and the renal control of extracellular electrolyte and acid-base status. The straw component was treated either with 50 g sodium hydroxide/kg dry matter (DM) (group B; two calves), or with 50 g or 100 g NaOH/kg DM and subsequently neutralized with hydrochloric acid (groups C and D ; two calves per group). In all groups the animals were given free access to tap water.3. Throughout the total 105 d experiment, all animals remained healthy and gained weight. Normal body growth (group A) was associated with a positive balance of NB (1-2 mmol/kg live weight (LW) per d) due to continuing deposition of dietary NB in 'new tissue', largely in the developing skeleton.4. During 105 d alkali-straw feeding, the animals showed a remarkable ability to cope with dietary loads of NaOH or sodium chloride, up to about 30 mmol/kg LW per d, without any significant disturbance of extracellular acid-base and electrolyte status or body growth rate. The surplus mineral and NB loads were absorbed and subsequently excreted in an increased volume of urine. Rates of mineral and NB retention were not significantly different from the reference values of group A and remained within the range of values reported from similar studies. In all groups, maintenance of normal whole blood and plasma acid-base and electrolyte status was accounted for by efficient renal control of the composition of the extracellular fluid compartment.

Effet du bilan électrolytique de la ration sur l’équilibre acido-basique et les performances zootechniques des animaux domestiques à fort niveau de production

“…Chez les ruminants en croissance, 10 publications ont été retenues, correspondant à 37 traitements. Deux publications avaient comme espèce modèle des moutons (Takagi et Block 1991, Fauchon et al 1995, cinq des veaux sevrés, âgés d'au moins 6 semaines (Wamberg et al 1985, Beighle et al 1988, Den Hartog et al 1989, Tucker et al 1991b, Jackson et al 1992, deux des bouvillons (Ross et Effet du bilan électrolytique de la ration sur l'équilibre acido-basique et les performances zootechniques... / 119 al 1994a, 1994b) et un des génisses (La Manna et al 1999). Les BE ont varié de -4 à + 700 mEq/kg MS, le pH sanguin de 7,34 à 7,47, les teneurs en bicarbonates de 19,8 à 31 mEq/L et la P CO2 de 29,7 à 48,7 mmHg (tableau 2).…”

Effects of feeding and short-term fasting on water and electrolyte turnover in female mink (Mustela vison)

“…In studies on animal nutrition the balance technique is commonly used as an experimental tool to assess changes in the whole-body content of macronutrients (Hegsted, 1976;Jeejeebhoy, 1986). Measurements of whole-body water, electrolyte and acid-base balance have also proved valuable for diagnostic purposes, particularly in the case of nutritional imbalances and/or metabolic disturbances (Wamberg et al 1976(Wamberg et al , 1985. In mammalian carnivores such as cats, ferrets (Mustela putoriusfuro) and mink, however, the process of urine collection is tedious, cumbersome and extremely sensitive to experimental errors due to the habit of these animals of squirting and spreading urine throughout the cage, including the corner of faecal deposits (Worden & Waterhouse, 1957;Russo et al 1986;Wamberg et al 1996~).…”