Enhanced reproductive performance of ewes given a sustained-release multi-trace element/vitamin ruminal bolus.

A sustained-release multi-trace element/vitamin bolus has been devised for administration to ewes in advance of mating. Each bolus contained 5.3g Cu, 50mg Se, 90mg Co, 100mg I, 3.2g Mn and 4.7g Zn with 268x10(3) IU Vitamin A, 54x10(3) IU Vitamin D and 800 IU Vitamin E. About 50% of each nutrient is released during the first 6 weeks. Thereafter the release rate slows and over the remaining life of the bolus (about 6 months extending to lambing time) the daily release rates are about 15mg Cu, 0.1mg Se, 0.2mg Co, 0.3mg I, 9.4mg Mn and 13mg Zn with 775 IU Vitamin A, 156 IU Vitamin D and 2 IU Vitamin E. In one study the proportion of twins born to ewes given the bolus was very significantly (P<0.001) higher than for the untreated ewes and greater than for those given a copper injection or copper oxide needles. In a second study the proportion of ewes given a bolus and having twin lambs was significantly (P<0.01) greater than for untreated ewes and significantly (P<0.05) fewer ewes were non-pregnant. In a third study, giving a bolus to shearling ewes tended (P=0.06) to result in fewer non-pregnant animals than for those untreated. Blood copper and Vitamin B(12) concentrations and glutathione peroxidase activities were above normal values throughout.

Sustained-release boluses to supply trace elements and vitamins to calves.

Cylindrical rumen boluses of a size (55 mm length x 18 mm diameter, density 2.9 g cm(-3)) appropriate for ruminating calves over 75 kg liveweight were constructed. The mean daily nutrient releases from two rumen boluses measured in rumen-cannulated cows were 62 mg Cu, 0.56 mg Se, 1.08 mg Co, 1.14 mg I, 38 mg Mn and 55 mg Zn with vitamins 3140 IU A, 628 IU D3 and 9 IU E. In a 123-day experiment with housed dairy calves given hay and a barley/soyabean meal mix, administration of two rumen boluses significantly increased plasma copper and blood glutathione peroxidase levels compared with unsupplemented control calves. There were similarly significant responses in a 143-day experiment with suckled beef-cross calves treated with two rumen boluses at grass. In both circumstances the basic diets provided inadequate allowances of both copper and selenium.

The effectiveness of copper oxide powder as a component of a sustained-release multi-trace element and vitamin rumen bolus system for cattle.

Copper oxide powder administered in the form of two experimentally produced sustained-release rumen boluses significantly increased blood and liver copper concentrations in growing sheep. It was estimated that 7% of the copper released was stored in the liver. In two farm observation trials administration of two standard production boluses significantly increased blood copper concentrations in out-wintered suckler cows during late pregnancy and early lactation, and in growing cattle at grass in the summer over periods of at least 170 and 123 days, respectively.