ChromLACT™ is a unique product containing chromium propionate. ChromLACT™ alleviates stress conditions of animals by reducing levels of cortisol in blood and increasing glucose utilization by peripheral tissues.

During stress conditions, excretion of chromium through the urine increases by 10 to 300 times. Due to excretion of chromium, tissue utilization of glucose decreases sharply and animal energy levels come down. Lower energy levels cause decreases in dry matter intake and lower milk production.

The following types of stress are present in dairy farms:

1. Heat stress
2. Cold stress
3. Calving stress
4. Lactation stress
5. Transportation stress
6. Vaccination stress
7. Handling stress

Stress causes the release of various hormones, which are part of the cow's natural 'fight or flight' mechanism, evolved over time as a response to dangerous situations. These hormones, such as cortisol (hydrocortisone) and adrenalin help prepare the cow's metabolism for the dangers it may have had to face, by, for example, increasing its heart rate and breathing, to help it escape a predator. Acute stress at milking time, for instance, is most obviously apparent in a reduced milk yield resulting from the release of adrenalin, leading to incomplete milk let down and increased residual milk.

Impacts of Stress on Dairy Farms

Feed intake: During high environmental body temperature, the animals try to maintain body temperature by minimizing metabolic heat (heat produced during feed digestion and nutrient metabolism) by reducing their feed intake, which leads to low energy intake by animals. At 40ºC, dry matter intake may go down by 40%. In heat stressed dairy animals 30 to 50% reduction in the efficiency of the energy utilization for milk production has been reported.

Milk let down: Cortisol decreases milk protein synthesis and inhibits the release of oxytocin. Stressed cows have poor milk let down and more residual milk, a risk factor for Mastitis. Typically, 10 to 12% of milk remains in the udder of slightly stressed cows and up to 15 to 17% of milk may remain in the udder of highly stressed cows. Residual milk is high in fat content,so when the fat-rich milk is held back in the udder the fat percentage will be lower in the milk output.

Immunity: Cortisol limits the white blood cell function and replication, which prevents these cells from protection from infection. Environmental Mastitis infections increase during the summer not only because more pathogens exist, but also because of heat stress increasing cortisol levels and suppressing the immune function. Increases in somatic cell count in milk during summer months has been reported to be a common phenomenon.

Nutritional Approach to Alleviate Stress in Dairy Animals

Supplementation of nutrients which play roles as antioxidants, such as Vitamin C, A and E, zinc and chromium can be used to alleviate the oxidative damage of environmental stress and improve the nutrient utilization for productivity. The Food and Drug Administration (US FDA) issued a regulatory discretion letter in 2009 which permitted the use of chromium propionate as a source of supplementary organic chromium in cattle diets.

Mechanism of Chromium in Glucose Utilization

1. Lactation and environmental conditions, mainly seasonal variation in air temperature (heat stress) are considered to be physiological stress which affects the animal’s biological system.
2. Stressors increase the blood cortisol levels, which lead to insulin insensitivity of the cells. Cortisol is known as the insulin antagonist. It does not allow the cells to utilize glucose which apparently results in a decrease in milk production. 
3. Under stressor influences, secretion of the cortisol increases, acting as an insulin antagonist through increasing blood glucose concentration and reduction of glucose utilization by peripheral tissues. 
4. Increased blood glucose levels stimulate the mobilization of the chromium reserve, chromium being then irreversibly excreted in urine (Borel et al., 1984; Mertz, 1992). Chromium excretion in urine is enhanced by all stress-inducing factors (Mowat, 1994). 

                                              Chromium excretion through urine

One of the strategies widely followed in developed nations to counteract heat stress is supplementation of chromium propionate in cattle diets. Chromium occurs widely in nature; it is a transition element, which occurs in a number of oxidation states. Burton (1995) has found that the most stable form is the trivalent state, which is the one involved in glucose tolerance factor (GTF).

One such form of organic chromium is chromium propionate manufactured by Kemin. Chromium propionate is the only source of chromium permitted in cattle diets as a result of a regulatory discretion letter issued by the US FDA in July of 2009. Chromium is a critical trace mineral required for healthy cattle. For rapidly growing animals or animals suffering from physiological stress (whether due to disease challenges, demands of high production or reproduction or heat) glucose utilization and its consequent impact on the utilization of dietary sugars is particularly important in a complete ration to maintain an animal's wellbeing. The predominant physiological role of chromium is to potentiate the action of insulin. As the active component of GTF, chromium is needed as a cofactor for insulin in moving glucose from circulation into peripheral tissues as such GTF.  

Chromium propionate supplementation at 5 mg chromium per day showed an increase in milk yield with the passage of time. These results show the essential role of chromium on improving the metabolic process for milk production. Chromium may promote the activity of IGF receptors, which have structural and functional homology to the insulin receptor and has direct effect on mammary synthetic capacity for consistent milk production responses. It is valid to consider chromium an essential dietary micronutrient, at least for stressful environments, high producing or intensively-reared ruminants.

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