Marvellous mineral management: the benefits of mineral analysis throughout the breeding season

Spring/Summer 2023

Eoin O’Brien

Irish livestock farmers are improving calving figures every year. In 2021, for example, there were 0.93 calves per cow per year, which is up from 0.91 in 2020. This is based on data from 14,234 herds. Despite this increase, we are still a considerable way off from hitting targets that have been identified as necessary to ensure a profitable dairy industry in Ireland.

Meeting these targets involves making sure animals are receiving all the nutrients they require to thrive and support a successful breeding cycle. However, up to 70% of grass samples taken in Ireland are currently low or deficient in magnesium, a key nutrient for breeding cows. Additionally, this year we have seen the wettest March and the fourth driest February in Ireland’s recorded history. These unpredictable weather conditions may have affected the mineral profile on farms throughout the country.

If you’re feeding your cows on grass this breeding season, you need to do a mineral test before any issues impact animal health and productivity. Read on to find out more about the importance of a successful breeding season, how mineral levels affect breeding cows, establishing a strong baseline for cow diets, and how to ensure optimal mineral levels with IAS.

The importance of a successful breeding season

Ensuring efficiency of milk production is a high priority for livestock farmers in Irish grass-based systems. This is greatly influenced by calving pattern, as having a short and effective breeding season where the maximum number of cows possible are put into calf can profoundly affect profit margins.

Cows will have a higher nutritional level later in the year. This can result in higher birthweights of calves, causing a higher chance of dystocia (calving difficulty). Calving too early can result in a loss of condition and lower re-conception rate due to the lack of adequate grazing opportunities.

As breeding season is happening on many livestock farms around Ireland, now’s the perfect time to consider adding analysis into your management plans. Reliable and accurate data will raise your chances of a successful breeding season for optimal profitability.

How do minerals affect breeding cows?

As you can see, a major factor in a successful breeding cycle is nutrition. When and what a breeding cow eats is vital for ensuring healthy and productive animals for optimal profitability. So, minerals play an integral role in a successful breeding cycle.

Going into breeding, we want a cow with a healthy immune system that displays a strong heat. This immunity is supported by trace minerals including copper, iodine, zinc, and vitamin E. Selenium also plays a key role in maintaining a healthy immune system, which is ultimately needed for a healthy womb and is critical for optimal fertility. Ensuring the right levels of organic selenium has also been shown to significantly reduce incidences of metritis and services per conception.

Deficiencies in certain trace minerals can lead to infertility if not dealt with early. Anoestrous behaviour (sexual inactivity) and silent heats in the herd, for instance, are often linked to deficiencies in copper, iodine and manganese. Major minerals such as phosphorus are also important in ovulation or cycling. If there is a deficiency of phosphorus, then anoestrous behaviour is once again a real possibility, lowering the chances of conception.

It is also important to remember that antagonist elements such as molybdenum, iron and aluminium are likely to ‘lock up’ or prevent the absorption of these important trace elements. As these elements are very prevalent in farms across Ireland, this is essential information to know from a general management and animal husbandry point of view. The levels of all these trace minerals, along with how they all interact, can vary greatly within areas and soil types, and therefore can have different effects on grazing animals.

Establishing a strong baseline for cow diets

Unfortunately, it can be hard to know if you are providing sufficient levels of key minerals until issues start to show in the cow—which is often too late. How can help cows have all they need to thrive throughout the breeding season?

Common mineral deficiencies prevalent in Ireland are phosphorus, copper, selenium, iodine and zinc. Cows should be supplemented with minerals at the appropriate rate to complement the minerals supplied in the grazed grass, as it’s crucial to have a certain amount of selected minerals supplied to the cows during breeding season to combat potential issues. As you choose your mineral supplements, be mindful that organic minerals are often better choice than inorganics because they are more bioavailable for absorption by the cow and have fewer interactions with antagonists. It is also advisable to have more than one source of minerals into the cows’ diet, especially during the breeding season.

For example, you may suspect a lack of phosphorus if your cows are licking stones or have a lower appetite. Whilst you might be tempted to feed minerals above requirement, this is expensive and will not boost fertility if there’s not a deficiency. Ensuring cows are well fed and have sufficient levels of all major and minor nutrients is much more important.

How do I ensure optimal mineral levels?

Once found, sometimes it’s too late in the season to correct deficiencies, adversely affecting productivity. How do we know for certain that there are any deficiencies before they become yield limiting?

Grass analysis is an important tool in establishing the overall mineral profile of a farm. In addition, the daily mineral supply of essential minerals such as calcium, phosphorous, copper, and zinc can be calculated, and accurate mineral supplementation recommended.

It is also advisable to look at the main output of the cows (milk) as well as the main input (fresh grass). Milk captures everything in the cow’s diet, from grass to supplements, so analysing the mineral profile of milk will help paint a full picture of your farm. Testing a bulk milk tank sample is a convenient way to identify your herd’s mineral profile and validate the effectiveness of your mineral nutrition programme. Analysis also helps determine any deficiencies before they affect animal health and productivity, so you can supplement your cows’ diets effectively and efficiently if required.

Overall, it is important to remember that healthy immune systems in your cows are vital to a successful breeding season for your herd. Minerals on their own are not secret ingredients that solve all fertility issues, but to achieve the results you want this breeding season, it is worth paying attention to the amounts and types of minerals being offered to your animals.

How IAS can help

Independent Analytical Supplies (IAS), leading Irish agricultural and environmental testing laboratory, offers grass and milk profiling analysis to help livestock farmers ensure a successful breeding cycle. IAS Laboratories has a proud tradition helping Irish farmers improve their management plans for more than a quarter of a century.

Our dairy mineral scan provides a mineral profile of the herd from a bulk milk sample, whilst the mineral profile of the farm is obtained from a fresh grass sample.

For more information – Call 059 9721022/ [email protected]