Advice from the Vet
In cattle, heat stress disrupts rumen function, decreases salivation and acidifies the blood. The body's buffering capacity - i.e., its ability to maintain a pH in equilibrium - is under severe strain. It is imperative that cows are given enough support to get through the hottest months.
Be careful though, because the combined effects of metabolic and ruminal acidosis can have a very negative impact on performances, growth, reproduction or immunity. In the worst case scenario, they may even result in death!
Boost the sodium and potassium levels in the ration
Adjustment of the mineral nutrition is at the top of the list of solutions to be put in place. By increasing the dietary cation-anion balance (DCAB) it becomes possible to, in particular, compensate for the deficit in sodium and potassium, eliminated via urine and perspiration during episodes of heat stress.
Kactus®, a food supplement developed by the nutrition company Vitalac, restores both the buffering capacity of the blood and that of the rumen by supplying Na and K ions. The goal is to bring the DCAB up to +300-350 mEq/kg of DM with a K content of 1.5 to 1.8% and Na content of 0.3 to 0.4% in the DM.
Its formula enriched in magnesia and plants also helps control oxidative stress. Kactus® is used as a periodic treatment as soon as the first hot days arrive, at a dose of 100 g per day per cow, and then 200 g/d/cow in July and August. The programme must be extended into September, at a dose of 100 g/d/cow, with the risk of seeing performances decrease significantly if a new heat peak arrives.
Various monitoring results of dairy farms have highlighted a return on investment of €130/cow and per summer, i.e. 5 Euros gained for 1 Euro spent. In terms of performances, Kactus® improved feed intake from 1 to 2 kg, milk production from 2 to 4 kg, while preventing the decreases in BT, something that is common during periods of heat stress.
Chelates to prevent “leaky gut” syndrome
The intake of chelated minerals also prevents leaky gut syndrome, which is common when animals are suffering from heat. Weakened, the intestinal epithelium lets various toxins pass into the blood. The ensuing inflammation results in an activation of the immune system. When mobilised, white blood cells consume a lot of glucose. Logically, the cow's energy needs increase even though it is not eating as much. The animal finds itself with an energy deficit.
Chelated micronutrients, which are easily assimilated, strengthen the intestinal barrier and limit the negative effects of this leaky gut syndrome. The use of yeast products and/or mycotoxin binders also helps keep the rumen healthy throughout the summer.