MINERAL BALANCE FOR IN CALF DAIRY COWS
The challenge is not getting them in-calf. It is keeping them in calf.
It is still a trend among some dairy farmers to concentrate on mineral supplementation only through the months of early lactation, and up to the completion of the mating period. In my view this misses the point.
Generally speaking while the energy and protein levels of the pasture may improve as the season progresses, the mineral levels in lush green spring pasture are often very low, and can reach their lowest level in the spring to early summer months. Cutting minerals at such a critical time can be likened to ‘saving cents while sacrificing dollars’. A fully formulated trace element supplement designed to be delivered throughout the season can cost anywhere from 50 cents to $1.70 per dairy cow per month depending on the types of mineral used and the levels required.
WE ASK A LOT OF OUR COWS AND IT IS AMAZING WHAT THEY WILL ENDURE AND STILL REMAIN PRODUCTIVE.
Given the usually challenging climatic conditions experienced on most New Zealand dairy farms during the spring, the average farmer certainly expects a lot from their cows. Firstly they go through the trauma of giving birth, then we extract large volumes of milk pretty much from day one, and then the cow is expected to become pregnant again. This all happens within a very tight window of time. Is it any wonder that cows struggle to recover when one stress event so closely follows the next?
GIVEN THE STRESSES INHERENT IN MODERN DAIRYING A COMBINATION OF HIGH ENERGY FEED, ADEQUATE FIBRE, AND A FINELY BALANCED MINERAL SUPPLEMENTATION PROGRAM ARE ALL CRITICAL IN THE LIFE OF A PRODUCTIVE DAIRY COW.
Over the last couple of decades as the productive levels of dairy herds have kept climbing, empty rates seem to have increased at a similar rate. Given the increases in the stress we are placing on these highly productive animals and without any major modifications in the feeding and supplementation regimes, these problems are expected to continue. Much research is now being expended on identifying the causes of this very costly issue. Research in this area to date has highlighted that conception is relatively easy to achieve – even under New Zealand conditions most cows will conceive on the first service. But, the real challenge is ensuring the cow receives adequate nutrition in order to maintain this initial pregnancy.
A major New Zealand study in 2005 titled “Pregnancy loss in dairy cattle in the Waikato region of New Zealand” and authored by McDougall, Rhodes & Verkerk., showed that out of every 100 cows inseminated, just 55 remained pregnant after 70 days. Scientific monitoring of the same matings showed that of the 100 cows inseminated, 89 pregnancies were initially established. Now on a typical dairy farm these cows will simply be re-mated, and many will subsequently become pregnant on either the second or third round. However, it is also likely that a large percentage of these same cows will not re-establish a viable pregnancy on those subsequent mating rounds, and due to economic factors may need to be culled.
I think it is worth considering how much more profitable the average dairy farm would be if they could increase the original first round pregnancies by even 10%?
You may also ask what happened to undermine initially viable pregnancies in these first 70 days?
There can be many factors involved in losing what started as a successful pregnancy and there are particular risk factors in the first 100 days following pregnancy. Successfully carrying the foetus through to full term is quite a balancing act. It requires the correct level of energy, which in turn requires a diet that supplies a balance of protein, carbohydrate, and in the case of a ruminant, good quality fibre. Also required is a correctly balanced ratio of minerals, and vitamins, critical factors in maintaining the very tightly balanced ratio of hormones required in early pregnancy.
Due to the nature of grass, grazing cows will normally be able to extract sufficient levels of most key vitamins from their diet and, given the correct balances of quality feed and fiber, can normally synthesize other vitamins from within the digestive system. But what about minerals?
FIRSTLY, WHY ARE MINERALS SO IMPORTANT?
Macro minerals (minerals required in larger volumes) such as calcium, phosphorous, and magnesium are essential for energy metabolism, blood flow both in utero and in the developing foetus, as well as the bone and tissue development required. Microelements or trace elements (minerals required in small amounts) such as zinc, copper, manganese, selenium, and iodine, are important in the maintenance of healthy enzymes, hormones, and in the synthesis of those essential vitamins that ruminants are so good at producing in the digestive process.
So how do you know what minerals are necessary for successful reproduction, and at what levels?
Recently much research has been expended looking into what particular minerals are key in driving and maintaining a healthy pregnancy in dairy cattle. Early on certain minerals were identified as being essential to successfully maintaining a pregnancy. These were, calcium, phosphorous, magnesium, zinc, copper, manganese, selenium, and iodine.
In a study published in 2017 called “Diselementosis as a risk factor of embryo loss in lactating dairy cows”, these elements were studied across three groups of cows in order to identify their individual importance. During the study different groups of cows were split depending on the outcome of their pregnancy, the first group experienced an uncomplicated pregnancy through to birth, the second group was identified as suffering from foetal growth restriction, the third group experienced embryo death. When comparing the two latter groups, those with reproductive issues against the group with no issues, the level of mineral deficiency measured was in each case directly related to the severity of the reproductive issue being experienced. The difference between the healthy group, and the other two groups (group II: foetal growth restriction, Group III: embryo death) were as follows: calcium -7.2% and -11.4%, phosphorous -9.1% and -9.8%, magnesium -23.5% and -27.2%, zinc -17.2% and -25.5%, copper -12.0% and -23.3%, manganese -15.2% and -15.8%, selenium -26.2 and -29.1%, iodine -21.2 and -33.4% respectively. This trial also demonstrated a strong correlation between higher daily milk yield and lower blood serum levels across the two problem groups. It will come as no surprise to many farmers that it is the higher producing groups of cows that most suffered the consequences of mineral deficiency.
This trial, along with other research is clearly showing that while reproductive issues in dairy cattle is a multi-factorial problem, there is also a strong correlation between mineral balance and successful reproductive outcomes.
DAIRY HERD MANAGEMENT & MINERAL BALANCE
When totalling up the empty rate as a herd manager it is always tempting to speculate on the cause and the reason behind the outcome, and this will be forever varied. Many factors can be outside the farmer’s control – a feed pinch at the vital time, poor transitioning from one feed to another, cold wet unseasonal conditions – all these factors can play a big part. As we know from research a number of pregnancies will terminate early for no apparent reason. However, taking all of this into account, much of the outcome is still in the hands of the herd manager. If the correct balance of critical factors is put in place ahead of time, there is every reason a large number of these initial pregnancies should go full term and not go on to become a statistic.
If the herd manager knows their feeds and has the ability to balance feed ratios correctly calculating the levels of energy, protein, and fibre they are already halfway there.
However, don’t short change on the other factors that may be just as important in maintaining the nutrition of the cow on a high plane. Ensure that your cows are receiving the right balance of essential macro and micro minerals in their diet. Don’t take it for granted that your cows are receiving the correct balance of minerals in their feeds. We know through testing of feeds that no single feed comes close to being balanced, no single feed supplies all the minerals adequate to the needs of lactation, let alone the demands of pregnancy. In fact, modern highly productive grasses are often worse than the older slower growing grass cultivars when it comes to mineral balance, this is even before you look at depleted soils and regional deficiencies. Then there are the crops, while they all have their attributes, each one also presents a different set of problems. Each crop has inherent deficiencies and many contain naturally occurring toxins (anti-nutrients) that can induce a number of mineral deficiencies.
Is it any wonder that we have issues?
DAIRY NUTRITION SUPPORT
At Agvance Nutrition we specialise in the formulation of lactation premixes for cow nutrition. Mineral premixes are fully formulated blends containing both macro as well as trace element salts, and can be built specifically to balance your feed requirements. We also produce both soluble and insoluble trace element blends.
For further mineral advice or guidance for your dairy herd, you are welcome to get in contact with the team here at Agvance.
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Article by Chris Balemi, Agvance Nutrition.