Achieving the correct balance of trace elements in dairy cow diets is vital for maximising performance, according to Animax company vet Dr Elizabeth Berry.
Selenium, cobalt and iodine are the main trace elements required, but copper may also be deﬁcient on some farms, says Dr Elizabeth Berry.
Trace element availability is inﬂuenced by soil type, types of forage and preservation of for-age, and also season. Generally fast growing forages have less trace elements present but often more soil is ingested in the autumn which can lock up trace elements.
She says: “Selenium is an important trace element because it is required for muscle growth in young animals and for disease resistance in all ages, with a higher rate being shown to be needed during the dry period in dairy cattle.
“Cobalt is another vital ingredient of a cow’s diet, as it is used for manufacture of vitamin B12. Young lambs and calves often have a high requirement for cobalt and quickly become deﬁcient.”
“A high quality trace element combination for dairy cows should be available in two forms – one with copper and one without.”
Dr Berry says most milk producers will know which trace elements are deﬁcient on their farms, but grazing land and conserved forage should be analysed on an annual basis as a precaution. All trace ele-ment mixes should be formu-lated in accordance with recommendations published by the National Research Council, with the farm’s advisers also consulted before an order is placed. Copper levels should be discussed with your vet.
While grass and forage testing and blood proﬁling will give an indication of trace element status, the results may not be wholly reliable.
“Each cut of silage will vary, according to ﬁeld conditions and cutting date,” she says.
“Forage and other feed levels will also change, according to the time of year. Blood proﬁling is only of limited use because it too will change depending on a variety of factors.”
Options for delivering trace elements to the cow include lick buckets, drenches and feed additives, but Dr Berry believes in the long term, a trace element bolus for cattle is the most accurate and cost effective method of providing these essential nutrients.
Letterkenny and Clydevalley herd yields: pHolstein average – 9,200kg at 4.08% fat, 3.35% protein pJersey average – 6,900kg at 5.32%fat, 3.83% protein
Most producers will have noticed lick buckets will attract certain cows, while others show little interest. Drenches can work well, but their effect is short-lived, while adding a trace element mix to the feed is also unreliable because it is difﬁcult to achieve an even spread, so some cows will ingest more and others less. Some producers depend on the concentrate feed to supply correct levels, but feeding to yield in the parlour will also lead to a variation in dietary provision.
When choosing boluses, Dr Berry says one consideration is whether it can be given with or without copper, and the levels of trace elements present and the release patterns of these ele-ments. There can be consider-able variation between them and how they release, so rely on one with good research behind it.
“The daily selenium recommendation for a lactating cow is just three milligrammes, which amounts to a packet of salt you would get with a beef burger when it is offered to a 180-cow herd. It is just not possible to mix this into 10 tonnes of forage with any accuracy. “In addition, feeds such as distillers’ grains and palm kernel already contain copper, so their inclusion in winter rations will affect nutritional status in those months.
“Using boluses for cows bi-annually is the best way to ensure the money you have spent on grassland production and other ingredients is backed up by the reliable provision of essential trace elements through-out the year.
“In general, you will pay for the convenience of using lick buckets and feed additives, and a bolus treatment will usually work out to be the least expensive,” she says.
ROBERT Hunter milks 75 ‘Letterkenny’ pedigree Holsteins and 25 pedigree ‘Clydevalley’ Jerseys at West Tarbrax, near Lanark. Milk is sold to Graham’s Dairies on a contract which pays a premium on fat content.
He started using Tracesure CU/I trace ele-ment boluses for all his adult cattle this spring, with Tracesure CU/I calf boluses given from about ﬁve months old. Previously, he had relied on the trace element content of bought-in concentrates for the milkers and provided a free-access powdered product for dry cows and youngstock.
Like many other dairy farmers, Mr Hunter responded to the fall in milk price by reviewing his management practices and taking a closer look at costings.
“I decided there was room for improvement on the feeding side,” says Mr Hunter. “I work hard at maintaining yields and quality and feed is a major input, so I need to make sure I utilise grass and silage to its maximum potential.
“Having done some re-search, I felt trace elements within the soil could be low and I know land in this area can be copper-deﬁcient and this factor can lock-up other nutrients. Retained cleansings were not a major problem, but I was seeing more cases than I would have liked. This made it difﬁcult to get the cow cycling again, taking up extra time and reducing output.
“I stopped and thought about one 15,000kg cow in particular – she was giving high volumes of milk but I was expecting her to per-form on just silage and concentrates.”
Mr Hunter uses the boluses twice a year and ﬁnds the system ﬁts in well with his management routine.
“The cows’ feet are checked at drying off and the bolus is administered at the same time. The second bolus is given at 100-days calved, when their feet are checked again. Supplying the correct amount of slow-release trace elements not only beneﬁts the cow, it must also have a positive effect on the calf she is carrying. From my viewpoint, I am setting my replacement heifers up for success while they are still in the womb.
“I think the bolus treatments are going to be cost effective, but in fact what is much more important is the fact there has not been a single retained cleansing since they were introduced. It is a cliché, but prevention is bet-ter than cure and, so far, this system is working for me.”