As calves go out to graziers, it is important to ensure that they have enough building blocks to support their growth into the 2025 season. With so many products available, it can be difficult to determine which are best for your calves. Below is a quick summary of three main trace elements that may affect their growth rate and some supplementation options:
Copper
Copper is important for maintaining a healthy nervous system, bone growth, immune functions and antioxidant activity. Cattle require feed levels of 10mg Cu/kg DM, if Mo levels are less than 1mg/kg DM, and Fe levels are less than 300mg/kg DM
A deficiency of copper can occur due to low levels of copper intake in the diet, or high levels of minerals that interfere with the absorption of copper in the guts. These minerals are Molybdenum (Mo), Iron (Fe), and Zinc (Zn). Eating high levels of soil affects the intake of these minerals, as does Zinc dosing for facial eczema prevention.
Peat soil copper to molybdenum levels can change dramatically over the season, with the highest molybdenum levels in spring. The ratio of Cu:Mo is required to be over 4.
Deficiencies
Clinical signs of copper deficiency include:
Rough coats,
Slow growth rates,
Severe scouring,
Bone fractures,
Difficulty in walking,
Delayed puberty
Impaired reproduction
Weight loss
Reduced milk production
Supplementation options:
Oral supplementation
There are a few options here, including:
Copper sulphate pentahydrate, which can be given through the dosatron or in fertiliser. For the latter, application in spring/autumn will cause Cu concentration to peak quickly then decline, but remain slightly elevated for months. Note that clovers tend to take up Cu more than grasses do.
A copper bolus, such as Coppermax or All-Trace, can be given no more than once a year and will be effective for 6-9 months.
Oral drench is a short term option, which will last between 1-4 weeks.
Direct supplementation
Copper injections, such as Multimin, are effective for 6-8 weeks in cattle and have the advantage of bypassing Mo in the gut.
Selenium
Selenium (Se) is important for the growth, health and metabolism of grazing livestock. It is present in many tissues and has antioxidant properties that help to protect and prevent damage to cell membranes, large proteins and nucleic acids, such as DNA. Se is also a cofactor for control points in thyroid metabolism and has roles in maintaining the integrity of the immune system.
NZ studies suggest that supplementation in a cow’s diet benefits herds up to 0.10mg Se/kg DM (2 mg Se/cow/day), with no additional advantage beyond that.
Deficiencies
Low dietary intake of Se causes cows to draw on stored forms of it in liver and red blood cells. Over time, this can lead to:
Reduced milk production
Impaired reproduction,
Reduced growth rate,
(More subtly) as increased risk of chronic diseases related to immunity.
The most common and important signs of Se deficiency are ill thrift and poor growth in calves.
White muscle disease (WMD) is also associated with Se deficiency and is characterised by non-inflammatory wasting of skeletal and cardiac muscle. Calves can be affected from 1-4 months of age.
Supplementation options
Farm treatments
Topdress fertiliser with Se prills
Selenium drench through in-line water dispenser
Drench - effective for several weeks
Oral supplementation
Mineralised anthelminitic drench
Subcutaneous injection - effective for 8-12 weeks
Prolaject B12 + Se (Selenate)
Multimin (sodium selenite).
Intraruminal bolus - effective for 8-12 months
Tracesure
All-Trace (sodium selenite).
Cobalt (B12)
Cobalt (Co) is an intrinsic part of the vitamin B12 molecule. Low dietary intake of cobalt leads to inadequate supply of B12 and eventual nutritional deficiency. Intake requirement rate for cattle is 0.06 mg Co/kg DM.
According to studies, 20% of herbage samples on NZ farms did not meet these requirements.
A cow’s diet can influence how much Co it needs, with grain fed cows requiring higher levels of supplementation, at 0.15 mg Co/kg DM.
Deficiencies
Cobalt deficiencies are more common in sheep, as they have higher requirements.
However, inadequate intake during the rapid growth period from birth to grazing can lead to suboptimal weaning weights and dull coats.
Supplementation options:
Oral treatments:
Mineralised anthelmintic drench. Water soluble supplementation is good for short periods (1-4 weeks). A lot is excreted in faeces in the first 2-4 days.
Intraruminal bolus, which maintain B12 status for 6 months. These are only suitable for animals with mature functional reticulorumen, where Co is released for up to 12 months.
Topdress fertiliser, in early spring, with cobalt sulphate.
Water dispenser with Co salts.
Direct treatments:
Prolaject B12 2000, which is effective for 4-6 weeks.
Want further help?
Give your KeyVet a call if you would like to discuss the best supplementation options for your stock, or if you have any concerns about trace element deficiencies in your calves.
References: Trace Elements and Minerals: Bayer.
