Absence of a weight gain response to vitamin B₁₂supplementation in weaned beef cattle grazing pastures of marginal cobalt content

Abstract

Forty female Angus crossbred calves aged 8 months were allocated to 2 groups based on liver vitamin BIZ levels and bodyweight. The treatment group was given monthly subcutaneous injections of 2000 J-tg hydroxycobalamin. From each group, . 5 animals were liver biopsied and 10 animals: serum and urine sampled at monthly intervals for 10 months. Pasture cobalt content in washed and unwashed samples averaged 0.051 mg/kg (0.866 J-tmollkg) and 0.061 mg/kg (1.04 J-tmollkg) DM respectively over the trial period. Mean liver vitamin B12 levels of the untreated group dropped during the spring and summer to 400 nmollkg, while the treated group remained above 640 nmollkg. Serum vitamin BIZ levels of the untreated group during the spring and summer averaged 87 pmolilitre, with the lowest mean monthly level of 73 pmolilitre occurring in November. Mean urinary methyl malonic acid remained low (less than 36 J-tmolilitre) in both groups. There was no weight gain response to vitamin BIZ treatment.

Effect of cobalt application on the cobalt status of pastures 3. Comparison of chelate and sulphate as cobalt sources for topdressing deficient pastures

“…;Clark etaI. 1981) andpastureCowaslow.However, Clark et al (1986)failedto obtainanygrowth response to vitamin BIZ injection incattleinthesameareaso the sitewouldbe in themoderate-marginal category of Co deficiency (Andrews 1971). The pasture had been established for about 3 years when the trial beganand consisted (visual estimate) of 30%white clover (Trifoliwn repens L.) and 70% perennial ryegrass (Loliumperenne L.)exceptduringsummer months whenthe proportion of ryegrasswaslower.…”

Lack of production response in grazing dairy cows supplemented withlong-acting injectable vitamin B12

“…For cattle, this is 0.06 mg Co/kg DM (Knowles and Grace 2010). Likewise, tissue concentrations that are indicative of vitamin B 12 status have been measured in a limited number of animal response trials (Clark et al 1986;. Concentrations of vitamin B 12 570 pmol/L in serum or 575 nmol/kg fresh tissue in liver are considered deficient.…”

“…In New Zealand Co/vitamin B 12 deficiency has not been documented in cattle. For example vitamin B 12 supplements given to weaned beef calves and dairy heifers grazing pasture containing 0.04-0.06 mg Co/kg DM did not elicit a growth response (Clark et al 1986;. In Australia, there was no milk yield response to Co supplementation in dairy cows grazing pastures containing 0.06-0.09 mg Co/kg DM (Stockdale and Grainger 1992).…”

“…It has been concluded from overseas studies that young cattle require 0.15 mg Co/kg DM and respond to Co/vitamin B 12 supplements when mean concentrations of vitamin B 12 in serum are 5100 pmol/L (Suttle 2010). In contrast in New Zealand, the dietary Co requirement has been determined to be 0.06 mg Co/kg DM (Knowles and Grace 2010) and no responses to supplementation have been observed when concentrations of vitamin B 12 in serum are 470 pmol/L (Clark et al 1986;.…”

The effect of trace mineral supplementation on natural and conventionally raised feedlot beef cattle

“…Tiffany and Spears (2005) suggested that low Co concentrations could limit gluconeogenic precursors because of the decreased circulating vitamin B12 concentrations leading to a decrease in methylmalonly-CoA isomerase activity, which is needed to convert propionate to succinyl-CoA in the liver. This would explain why, in progressive stages of vitamin B12, deficiency an increase in circulating MMA in the blood and urine can occur (Clark et al, 1986). When various concentrations of Co was supplemented to Angus steers (274 kg) as…”