Animals – Lifestyle in the spring

If you have any farm animals due to give birth in the spring, you will know that magnesium is a very important macro-mineral for cows around calving time, to help their internal machinery to work properly at and after calving. Among lots of other jobs, magnesium primes their parathyroid gland to release a particular hormone, at the correct time, in the correct amount, to mobilise calcium from the bones into the blood when their milk comes in. Calcium levels in the bloodstream are tightly controlled by the body, and for good reason. If this whole system doesn’t work properly, problems occur like weak “downer” cows (milk fever and grass staggers), trouble with delivering their calves and infections including mastitis.

Magnesium really needs to be taken in daily, from two to three weeks before calving, as it is not stored in the body, and should be continued until after the grass growths have slowed (generally in November/December). Causmag (magnesium oxide) mixed with molasses as a slurry, spread over hay to be fed, was the age-old tradition for this shortfall, pre-calving. Another way is via the Crystalyx Pre-Calver lick mix that is left with the cow(s). Research carried out in New Zealand showed that giving access of Crystalyx Pre-Calver to dairy cows pre-calving and early lactation significantly reduced the incidences of milk fever, mastitis and the need for assisted calving. Crystalyx Pre-Calver has also been shown to substantially increase the levels of selenium and zinc found in the cow’s bloodstream. These days, there are many options for magnesium supplementation, but ANY is better than none for the sake of a smooth running calving period. At the same time, it is very important to never supplement calcium pre-calving, as doing this really upsets the magnesium priming of the parathyroid, also causing problems with the calcium magnesium balance when their milk comes in.

Consider using a “starter drench” like Calstart for high risk cows at the point of calving. These are cows that are greater than seven years old, or very fat, or have a history of problems at previous calving times. The DairyNZ website holds a lot of free information to help set your block up for a trouble free spring, including some great tick lists for calf rearing. Check out “DairyNZ Spring Survival Guide” and a word to the wise … try to avoid buying calves from saleyards, as their paediatric immune systems are the target for the milieu of pathogens there.