Planning a Nutritious Diet for Heat-stressed Cows

Article Summary:

In response to summer heat, the digestion process slows down to regulate the body temperature, which results in less feed intake by heat-stressed cows. Your cow needs a balanced intake of carbohydrates, proteins, minerals, vitamins, fats, and water every day. We recommend three nutritional strategies for your heat-stressed cows: increase their fats and protein intake; feed them fibre and optimum amounts of starch; use feed additives. Benefit from planning today!

You might have noticed how you don't feel like eating anything in summer. If you have, you are not alone. Let me tell you an interesting ingenious fact behind it.

As the temperature in our surroundings rises, our body tries to regulate our temperature by trimming down functions that generate heat. One such function is the digestion of food which slows down in summer. There you have it, an amazing built-in mechanism to stay cool in summer. The same is true for cows.

So, exposure to summer heat followed by heat stress brings us to the topic of how to maintain a cow's health. After all, high-quality milk yield depends on the nutritional value of feed intake.

To walk through the summer, we would need a comprehensive nutritional plan for dairy and beef cows. We would talk about the nutrition a healthy cow needs in her daily diet. Also, how heat stress can lead to nutritional deficiencies in cows and how progressive farms are dealing with it.

We will discuss three nutritional strategies to feed heat-stressed cows. Without further ado, let’s take the plunge.

So, what are we aiming at?

The aim behind the summer nutrition plan is to consider the following factors when making a diet plan for cattle;

1. Cows need their required metabolisable energy through daily intakes
2. They need essential nutrients through their diet, every day
3. They ought to conserve energy for higher milk production
4. They need to fight off the heat stress and maintain a balanced diet

List of Nutrients your cows need in their daily feed ration

We are what we eat, says the adage. It is surprisingly more true for cows; a balanced, healthy and nutritious diet is primary to high quality and a good quantity of milk production. Now that we know the importance of nutrients, we are going to list them down and ensure your cow is fed on the best feed.

1. Water:
   No one can go on a single hot summer day without water. It is by far the most essential component of a balanced diet for cows and cannot be stressed enough.
   Note that water need is temperature-dependent; an increase of 4C increases the water intake by cows to 6-7 litres a day. That being said, the high yielding cow would drink 160-200 litres of water on a hot summer day.
   Let me say this again, ensure your cows are super hydrated.
2. Carbohydrates:
   Carbs make up 70% of the diet of cows. Both fibrous and non-fibrous carbs are the source of energy for cows. The fibrous component comes from dry matter while the non-fibrous component comprises sugars, fructans, starch, organic acid, and pectin.
   Carbohydrates are the main component of a cow’s diet. Fibre boosts rumen health by maintaining rumen pH. Sources of carbs are forage, roughages, grains, and sugars.
3. Proteins and amino acids:
   Protein comprises crude protein content, amino acids, dipeptides, nucleic acids, NH3, and other non-protein nitrogen compounds. Cows need proteins and amino acids to produce enzymes, milk proteins, immunoglobulins, muscles and body tissues.
4. Fats:
   Fats, if fed the right way, lead to higher quantities of milk production. Fats are in everything a cow eats, except for water and minerals. For instance, carbs have 3% fat, oilseeds like canola, soybeans etc. have 20% fat, lest we forget, sunflower seeds have 45% fat!
   Point to remember: Fat content in a cow's feed should not exceed 8% of total dry matter.
5. Minerals:
   The list of minerals a cow need is a long one. Calcium is the most essential for lactating cows. It's added in feed in the form of calcium carbonate. Other macrominerals are sodium, potassium, chlorides, magnesium, and sulfur. Deficiencies of trace minerals like copper, zinc, iodine can cause various health problems. So, read about recommended percentages of these minerals here.
6. Vitamins:
   Cows require vitamins in recommended amounts. Some crucial vitamins are A, D, E etc. Cows are given supplements to fulfil the needs of vitamins. Consult your vet for a supplement program.
7. Bonus:
   Raising a cow for high milk yields starts from raising healthy calves and heifers. Read a detailed guide on components of a balanced diet and where to find them in our informative article.

Three Nutritional strategies for heat-stressed cows

We already talked about heat stress in great detail and laid down a working plan to keep cows cool when it's reigning heat. We also discussed the impacts heat stress can have on the mating behaviour of cows. It is time to carve feeding plans for heat-stressed cows.

Heat stress reduces dry matter intake by 10-20%. This low intake of feed combined with the energy-intensive heat dissipation process leads to nutritional deficiencies, thus worsening the negative effect of heat stress.

Three strategies to cope with heat stress.

1. Increased amounts of fats and proteins in the diet
   This nutritional strategy works well for high yielding cows. It also works for cows that are under great metabolic stress. We can use supplementary fat sources, like vegetable oils, while the amino acid requirement is fulfilled by proteins. Take into consideration the following points when utilizing this strategy:
   • Cows digest fats more efficiently than starches and fibres. Fats produce less metabolic heat.
   • Do not feed too much fat as it will negatively impact the microbial digestion in the rumen and further lower the feed intake in cows.
   • More than 6% and less than 8% is ideal in total dry matter.
   • Carefully manage the ratio of saturated fat vs unsaturated fat through the feed.
   • Remember, summer pastures are lower in protein content, and microbial function in the rumen is compromised. To address this, feed only high quantity protein sources. They are easily digested in the small intestine and help offset lower microbial activity in the rumen. Thus, high fat and protein feed makes an excellent diet for heat-stressed cows.
2. High-quality fibre and optimum amounts of starches in the diet
   Since daily dry matter intake is reduced in summer, managing the quality and quantity of fibres and starches can assist offset the effects of heat stress. Consider the following tips when adding fibre for heat-stressed cows:
   • Feed only high-quality fibre, it will enhance the nutrient density and sustain rumen stability. Thus, assisting heat stress management.
   • High-quality fibre produces less metabolic heat. In comparison, low-quality fibre produces excess heat, does not fulfil the nutrient need, and gives unnecessary dietary bulk.
   • High-quantity of high-quality fibre makes it possible for the cow to return to good health after the hot period ends.
   • Using mixers in combination with fibres adds flexibility to the feed.
   Starches make a good source of glucose, plus heat-stressed cows have a greater need for glucose consumption. Forethought must be given when selecting the source of starch.
   • Use a form that ferments slowly and then provides a steady supply of glucose.
   • Slow starch fermentation assists in feed digestion, reduces rumen energy yield and allows glucose formation in the liver.
   • Excessive starch fermentation reduces the risk of ruminal acidosis.
   • Fast starch fermentation quickly releases energy and brings down rumen pH.
   • Rumen digests starch. The leftover starch from the rumen is digested in the small intestine where it produces glucose used by gut tissue.
   Thus, high-quality fibre combined with the right amounts of starch improves the cow’s ability to fight off heat stress while maintaining a sustainable intake of essential nutrients. Heat stress also affects the cow’s ability to digest grains. Farm management can depend on manure screening to assess the efficiency of grain digestion. This can help farms make an informed decision when planning a nutritional diet.
3. Using feed additives for heat-stressed cows
   Feed additives can assist cows in coping with the effects of heat stress in many ways. Some of these additives are rumen modifiers, niacin, betaine and yeast metabolites. They help cows in many ways;
   • Rumen modifiers assist by positively changing the balance between the population of different microbes in the rumen. They also change the proportion of volatile fatty acids these microbes produce in the rumen.
   • Some common rumen modifiers are; monensin, tylosin, virginiamycin, etc. We recommend consulting your nutrition advisor before using any rumen modifiers or the best results.
   • Cow produce ~2.5kg/day of saliva rich in bicarbonate. This saliva is a natural buffer against altering stomach acidity. It also helps keep rumen pH within an optimal range and supports good gut bacteria.
   • Heat-stressed cows not only have low amounts of bicarbonate in their saliva, but they also drool. This drooling means natural buffering is compromised and there is a risk of lower rumen pH.
   • Therefore, including buffers in the diet of heat-stressed cows is also necessary. Consult your nutritionist for recommended daily feed rates.

These three nutritional strategies can save your cows from heat stress while ensuring a high milk yield of good quality. Make a nutritional diet plan today. This brings us to the end of the article.

Act now and until we meet again, Happy Feeding!

- The Dedicated Team of Pasture.io, 2021-12-22