15 August 2022 - As dairy farmers strive for greater productivity, they have to feed more concentrates to provide cows with enough energy for higher milk volumes. However, high starch, low fibre diets pose a risk to the delicate microbial activity in the rumen. Rapid fermentation of starch and sugar creates faster acid production in the rumen, which lowers the pH and affects microbial activity, causing sub-acute ruminal acidosis, or SARA.
Fortunately, acidity regulation is a problem that Omya, a specialist in calcium carbonate solutions, is well-equipped to address. The Swiss company has decades of experience in the agricultural industry, where its products are used to correct pH imbalances in soil and to improve layer hen nutrition, among other applications. Recently, it has channelled its considerable expertise in mineral nutrition into the development of OmyaFeed C MgO.
Today, we hear from Marta Aguirre, Technical Services Animal Nutrition at Omya, about the company’s plans to address acidity regulation in the dairy industry with an effective ruminant buffer that saves space in the ration.
[Feedinfo] Let’s start by getting a handle on why SARA is such a problem for the dairy industry. What are the economic and animal welfare impacts of the condition?
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[Marta Aguirre] SARA is a big problem for the dairy industry because it has such an impact on cow welfare and therefore milk production. It’s difficult to assess the extent of SARA incidence without post-mortem examination but it has been suggested that at least a quarter of all high yielding dairy cows suffer from the disease. The worldwide dairy herd is around 264 million cows, but 75% of milk production is supplied by 125 million more intensively farmed animals. Figures from the US estimate the cost of SARA at $400 per cow per lactation, so if a quarter of those high-producing animals have SARA, the economic impact runs into billions. That’s made up of productivity and quality reductions, with lower milk volumes and reduced butterfat percentages, as well as the cost of veterinary attention, premature culling and increased death. |
Marta Aguirre |
From an animal welfare perspective, SARA is a disease that might not be obvious to the casual observer, but which will be felt keenly by the animal. Cows with SARA suffer from reduced appetite leading to loss of body condition, often accompanied by scour which can add its own welfare complications. One of the biggest issues caused by SARA in a herd is lameness, with sole ulcers, bruising and abnormal hoof growth making life very uncomfortable for the cows.
[Feedinfo] Do you believe there is a widespread understanding about how common SARA is, how to identify whether you have an issue with SARA, and how to combat it? Or is it an issue that continues to perhaps go undetected and unaddressed?
[Marta Aguirre] I think most dairy farmers with high-yielding herds have some knowledge of animal nutrition and the need to protect their herd against acidosis. It’s difficult to accurately diagnose, though, so farmers need to watch out for some key symptoms. A decline in milk production and quality, linked with reduced dry matter intake and loss of body condition, will be a common indicator. Farmers will also notice other symptoms such as scour and lameness which may well be related to SARA. A good rule of thumb is to assess how widespread lameness is in the herd: over 10% and you probably have SARA to blame.
Of course, it’s much better to prevent SARA from occurring than to try to treat it when cows are already suffering. There are some standard welfare procedures which will help prevent SARA, for example making sure that the animals have enough fibre and the opportunity to relax and chew the cud, which encourages the production of saliva, a natural buffer. Any changes to the diet should be introduced over time, to allow the rumen microbes to adapt.
[Feedinfo] Under what conditions are animals most at risk for SARA? Is it more problematic at certain points in the reproductive cycle, with certain feeding practices, or at particular times in the year?
[Marta Aguirre] Cows most at risk of SARA are those fed on high concentrate diets designed to deliver greater yields, so for herds kept indoors or intensively managed herds, there is a risk of SARA all year round, except during the dry season. But even grass-fed cows can suffer from SARA. In the spring, fresh grass has a high sugar and oil content, but is low in fiber, so farmers should be aware of the acidosis risk.
SARA is caused by the accumulation of volatile fatty acids (VFAs) in the rumen. As feed is digested, VFAs including acetate, propionate and butyrate are produced. If this happens quickly, as it does with high sugar and starch rations, then the pH in the rumen drops. An animal is said to be suffering from SARA if the pH stays low (between 5.2 and 6) for a prolonged period each day.
All cows are more likely to suffer from SARA early in the lactation and there is evidence that cows in their first lactation have a higher risk of acidosis.
[Feedinfo] What is OmyaFeed C MgO? What data do you have about the benefits it can provide for dairy cattle?
[Marta Aguirre] OmyaFeed C MgO is an advanced formulation feed supplement, made from micronized ground calcium carbonate and magnesium oxide. It offers farmers an effective preventative or curative solution for SARA and mineral deficiencies in intensively farmed dairy cows and other ruminants.
We have commissioned independent trials in the laboratory and on-farm to demonstrate the benefits of OmyaFeed C MgO. At IRTA Research Institute in Spain, scientists evaluated the performance of dairy cows under induced SARA conditions, measuring the effect of OmyaFeed C MgO against a standard mix of sodium bicarbonate, calcium carbonate and magnesium oxide. The calcium supply was kept constant between the rations and rumen pH was measured at five-minute intervals for four weeks to assess rumen health. In week two, they also evaluated the calcium and magnesium balance.
Cows supplemented with OmyaFeed C MgO spent fewer days with pH lower than 5.8 than those supplemented with sodium bicarbonate, without affecting milk yield or fat content. On top of that, milk proteins were higher in the cows fed with OmyaFeed C MgO, which gave a better fat: protein ratio.
[Feedinfo] Can you explain the importance of having a rapidly absorbed and highly bioavailable calcium and magnesium for this application? How does OmyaFeed C MgO measure up on this front?
[Marta Aguirre] Livestock needs a readily available supply of calcium and magnesium, but these are particularly important nutrients for dairy cows. Calcium is a key constituent of milk, with about 1.2g of calcium in every litre of milk produced, and it’s generally acknowledged that it is more available when provided as a mineral supplement than as part of forage or other feedstuffs.
Magnesium is an essential nutrient for many physiological processes in dairy cows, from fibre degradation in the rumen to milk fat synthesis in the mammary tissue. What’s important to remember though is that the magnesium source must be easily absorbed otherwise deficiency will follow, alongside symptoms of tetany or milk fever.
When cows are suffering from SARA their uptake of calcium and magnesium slows down, so it’s therefore essential that farmers and feed manufacturers take this into account when formulating the ration.
OmyaFeed C MgO has proven bioavailability for dairy cows, as shown in our IRTA trials. We measured calcium and magnesium absorption and found that whilst calcium intake was lower in the cows fed with OmyaFeed C MgO, there was no significant difference in the amount of calcium digested, demonstrating more efficient absorption. For magnesium, the intake was marginally higher, but the absorption difference was 60% higher than with the conventional mix.
In a university trial in Spain, scientists measured calcium absorption of OmyaFeed C MgO against seven commercially available products and found that our product gave the highest calcium availability at 94.4%.
[Feedinfo] What makes OmyaFeed C MgO an improvement over other options for keeping SARA under control?
[Marta Aguirre] Many farmers control SARA by adding a buffer or alkaliser to the feed, compensating for reduced saliva secretion and neutralising excess rumen acidity. Many feed supplements designed to manage SARA contain sodium bicarbonate as a buffer.
This keeps the rumen pH in a narrow range whereas an alkaliser like magnesium oxide raises the pH according to the amount added.
There are two key issues with sodium bicarbonate that OmyaFeed C MgO overcomes. Sodium bicarbonate has to be fed at high rates of around 250 g/cow/day, whilst each cow only needs 130g of OmyaFeed C MgO per day. The other issue with sodium bicarbonate is that because of its solubility, it doesn’t provide any long-term buffering effect. OmyaFeed C MgO, on the other hand, is made from micronized natural minerals which act as a buffer to keep ruminal pH at the optimal level.
OmyaFeed C MgO can be used to treat cows with SARA or to help prevent future incidence of the disease. One of the main benefits for farmers is the cost savings. OmyaFeed C only costs about 7 Euro cents per cow per day. It is also used at a much lower rate than other supplements, leaving almost 200g space in the ration which can either be used for other feedstuffs or to reduce the overall cost of the ration. With the rising cost of inputs, this is something that farmers are finding very attractive.
It is also important to farmers is that the product is easy to use. OmyaFeed C MgO is a low-dust, compacted product which farmers can mix easily in the ration without it settling. It’s palatable for the cows and can be added to either concentrated feed or to silage. But the most important benefit to farmers is that OmyaFeed C MgO solves the problem of SARA with lower dosage and a lower cost than other feed supplements.
[Feedinfo] How is this a natural extension of Omya’s portfolio?
[Marta Aguirre] Omya is one of the world’s leading producers of natural minerals, with customers in markets ranging from construction to food ingredients, and water treatment to paper production. We started working with agriculture almost 70 years ago, helping arable farmers to improve soil health and crop production. More recently our scientists have been developing similar products to combat productivity challenges in the livestock sector and solve animal welfare problems.
Our interest in SARA developed because we recognized that acidosis was a major issue for dairy farmers and we knew how to use natural minerals to correct and buffer pH, whether in soil, water or even potentially in animals. Omya employs nutritionists and veterinarians to work with our chemists to develop new products for livestock farmers.
For example, we have created a unique supplement for egg producers with the right level of absorbability to make sure that calcium is available to the hens when they are laying the eggs, which is of course during the night long after they have eaten.
[Feedinfo] I have understood OmyaFeed C MgO is at the beginning of its roll out, having been subject to a limited launch late last year. Can you explain where OmyaFeed C MgO is currently available, and what markets will be the focus for the product for 2022?
[Marta Aguirre] We are focusing our attention on the key dairy markets in Europe to start with. We will add other markets over the coming months.
Published in association with Omya International AG
