Iodine has a direct impact on growth rates as it is incorporated into the thyroid hormones which control metabolism, promoting efficient live weight gain.
Annie Williams, Animal Scientist with Agrimin says that many beef units fall short on achieving optimum growth rates because animals do not receive adequate levels of trace elements at grass.
She says that with increased feed costs, many producers will be looking to get increased production from forage and that unless shortfalls in trace element supply from grazed grass are addressed it is likely that animals will fail to grow at the optimum rate.
'On many farms, tremendous emphasis has been placed on improving growth and perf¬ormance in pre-weaned calves. Ms Williams says that similar attention to detail needs to be paid at grass to maintain optimum growth.
She says that while trace elements are only required in minute amounts in the diets of growing cattle, usually less than lOOmg/kg dry matter per day, they are essential for main¬taining heath and immunity as well as maximising productive performance. By getting the correct trace element balance, improvements will be seen in feed intake, digestibility and feed conversion leading to improved growth and production.
'While grazed grass can provide the energy and protein cattle require, particularly in the first part of the grazing season, it can often be low in essential trace elements. With concentrate feeding commonly reduced at grazing, this can mean animals face a shortfall unless they receive effective alternative supplementation.'
She says Copper, Cobalt, Selenium and Iodine are the most important trace elements in growing cattle. Copper shortfalls are frequently seen in young animals at pasture and can lead to poor growth rates and potential increased rates of lameness. In later life copper shortfalls can also lead tG poor fertility in suckler cows and heifers.
'Both Selenium and Vitamin E play a key role in promoting a healthy immune system and preventing cell damage. Skeletal, cardiac and respiratory muscles are the most susceptible to damage and can result in significant growth checks. In severe cases if the cardiac muscle is affected the animal can die suddenly.'
She says trace elements have an impact on growth rates by improving efficiency of digest¬ion. An adequate supply of Cobalt is required in the rumen to allow the micro-organisms to synthesis Vitamin B12 which is important for breaking down feed, maintaining appetite and ensuring efficient live weight gain.
'Iodine has a direct impact on growth rates as it is incorporated into the thyroid hormones which control metabolism, promoting efficient live weight gain. The primary cause of Iodine shortfalls is low levels in the forage. The secondary cause, however, which is often over looked is feeding goitrogen based feeds such as brassicas and some legumes e.g. fodder beet and turnips which inhibit Iodine availability. This can be more of a problem in the late summer when these crops can be introduced to supplement grazing.'
Ms Williams says the most effective way to supplement cattle is with an eroding bolus which will provide a guaranteed intake of all the key trace elements for the full grazing season ensuring optimum health and growth rate.
'Bolusing is the only way to be sure that every animal will have an adequate intake, unlike methods such as free access minerals and blocks which rely on animals voluntarily consuming enough every day. Blocks have the added downside that they are attractive to badgers and other vermin.
'It is important to make sure that the calf does not loose condition at weaning. It is therefore vital that trace element shortfalls are not present at this stage. Bolusing at turnout can be easily combined with other manage¬ment activities such as worming to reduce the number of times heifers have to be handled, making it easier and more cost-effective.'