Influence of dietary cobalt on performance, nutrient digestibility and plasma metabolites in lambs

Effects of folic acid and cobalt sulphate supplementation on growth performance, nutrient digestion, rumen fermentation and blood metabolites in Holstein calves

To investigate the influences of cobalt (Co) and folic acid (FA) on growth performance and rumen fermentation, Holstein male calves (n 40) were randomly assigned to four groups according to their body weights. Cobalt sulphate at 0 or 0·11 mg Co/kg DM and FA at 0 or 7·2 mg/kg DM were used in a 2 × 2 factorial design. Average daily gain was elevated with FA or Co supplementation, but the elevation was greater for supplementing Co in diets without FA than with FA. Supplementing FA or Co increased DM intake and total-tract nutrient digestibility. Rumen pH was unaltered with FA but reduced with Co supplementation. Concentration of rumen total volatile fatty acids was elevated with FA or Co inclusion. Acetate percentage and acetate to propionate ratio were elevated with FA inclusion. Supplementing Co decreased acetate percentage and increased propionate percentage. Activities of xylanase and α-amylase and populations of total bacteria, fungi, protozoa, Ruminococcus albus, Fibrobacter succinogenes and Prevotella ruminicola increased with FA or Co inclusion. Activities of carboxymethyl-cellulase and pectinase increased with FA inclusion and population of methanogens decreased with Co addition. Blood folates increased and homocysteine decreased with FA inclusion. Blood glucose and vitamin B₁₂ increased with Co addition. The data suggested that supplementing 0·11 mg Co/kg DM in diets containing 0·09 mg Co/kg DM increased growth performance and nutrient digestibility but had no improvement on the effects of FA addition in calves.

Effect of trace mineral source on biochemical and hematological parameters, digestibility, and performance in growing lambs

To study the efficacy of organic trace mineral supplementation on blood parameters, digestibility, and growth as compared to inorganic sources, 18 Zandi male lambs (with initial body weight, 28.5 ±1.4 kg and 110±5 days old) were divided into three groups of six animals in each in a completely randomized design. Lambs in the control group were fed basal diet containing 63 kg/100 kg of concentrate mixture, 22 kg/100 kg of alfalfa hay, and 15 kg/100 kg wheat straw. Animals in the experimental groups were additionally supplemented with trace minerals supplied by sulfates or a diet in which 25.7 ppm Zn, 14.3 ppm Mn, 8.9 ppm Cu from mineral-amino acid complex, and 0.86 ppm Co from Co glucoheptonate replaced with similar amounts of Zn, Mn, Cu, and Co from sulfates. All lambs were kept in individual pens with cemented floor and provision of individual feeding and watering. Lambs fed with either organic or inorganic trace mineral supplement showed higher dry matter intake and growth rate and better feed conversion efficiency (P<0.05) as compared to the control group. Blood glucose, urea nitrogen, cholesterol, and hepatic enzymes were similar among the treatments. Triglycerides (P<0.01) concentration was lower for mineral-supplemented groups. Blood vitamin B12 concentration increased with mineral supplementation and was higher for the lambs fed with organic source of trace elements as compared with those fed with inorganic mineral and the control diet (P=0.04). The results of this study showed that feeding organic trace elements improves growth performance of finishing lambs but did not affect nutrient digestibility and blood parameters.

A comparison between different concentrations and sources of cobalt in goat kid nutrition

There have been extensive studies in sheep and cattle considering cobalt (Co) supplementation and its effects on vitamin B12 concentrations in the body. However, there are limited studies on goats. The aim of this study was to compare two different sources of Co (sulfate v. glucoheptonate) at two different concentrations (0.25 and 0.5 mg/kg dry matter) in goat kid nutrition, and to evaluate the effects of these supplements on performance, serum vitamin B12, blood biochemistry and rumen volatile fatty acids. For this purpose, 30 weaned male goat kids were randomly allotted to five treatments. Serum vitamin B12 increased during the trial in the Co-supplemented groups. Co supplementation increased serum glucose concentrations. On day 35, Co-supplemented groups had greater glucose concentrations compared with control. Propionic+iso-butyric acid concentrations increased only in the 0.5 mg Co glucoheptonate treatment (P<0.05). Our results suggest that, despite the two sources of Co proving mostly similar, the main advantage of Co glucoheptonate compared with Co sulfate was in the ruminal synthesis of vitamin B12. However, although providing Co at National Research Council recommendation levels maintained vitamin B12 above or at normal concentrations, Co supplementation of the Co sufficient basal diet increased vitamin B12 and glucose concentrations.