A “Stress Free Summer” For Poultry Producers
The stress of summertime heat can bring down egg production in layers and breeders, increase feed conversion ratio (FCR) in broilers and affect the overall performance of birds. Typically, poultry producers may see up to a 10 percent drop in production during summer months. With India’s current drought conditions and hotter-than-normal predicted temperatures, producers are expecting to see a 25 to 30 percent productivity drop this summer
Here are some guidelines poultry producers can use for a “Stress Free Summer”:
Poultry farms that are surrounded by trees and in a breezy area will have fewer problems in summer season. Beyond the location of your farm, roof insulation and increased ventilation with fans can help broilers withstand moderately hot weather. Producers should avoid overcrowding and provide shade to overhead water tanks and pipe systems.
In extremely hot weather, shade and breeze may not be sufficient; and evaporative cooling systems such as sprinklers, foggers or pad cooling may be necessary. These systems can help bring down temperatures significantly when relative humidity is low. Use of fans without an evaporative cooling system may be harmful in extremely hot weather if only hot air is blown into the house.
Feed withdrawal from 9 a.m. to 4:30 p.m. can be effective in reducing heat stress mortality. Feed intake and digestion produce nearly seven percent additional body heat which can last four to five hours after feed intake. This should not coincide with the hottest part of the day, typically 2 to 3 p.m. If biosecurity is poor, feed withdrawal may lead to coccidiosis or necrotic enteritis. Necessary medicines should be kept on hand in case a disease arises.
To compensate for reduced intake in the summer, feed should be made denser with nutrients, vitamins and minerals. As the hot season progresses it may be necessary to fine-tune feed formula throughout the summer. The following elements should be included in a summer feed formula to help control heat stress:
- Crude proteins. Crude protein levels in feed should not be increased and protein from vegetable sources should be used. Proteins in general, and those from animal sources, in particular, have higher heat increment values which produce more internal heat. Secondly, vegetable proteins (soya, sesame, sunflower) are preferred in the summer because they are rich in arginine. Under heat stress, arginine absorption is low which can result in plasma amino acid imbalance and increased catabolism of amino acids adding to body heat. While keeping protein levels the same, crucial amino acids may be increased to compensate for reduced feed intake.
- Fats. Fat should be increased by two to three percent at the cost of carbohydrates without changing ME. Fats are good in summer because they have a lesser heat increment value, which provides a better cooling effect in the body.
- Vitamin C and chromium. Because of the release of corticosteroids in heat stress, there is increased demand for Vitamin C by adrenal glands for the controlled production of hormones needed for gluconeogenesis. In heat stress, there is also reduced synthesis and partial depletion of Vitamin C.
If laying hens are exposed to high ambient temperatures, the supplementation of chromium and ascorbic acid has been shown to improve the retention of minerals such as iron, calcium, phosphorous and zinc (Sahin and Sahin, 2002). In the same study, the authors also observed a reduction in nitrogen excretion and have suggested the combination of chromium and ascorbic acid to be a protective stress management strategy. The reduction in loss of minerals was presumed to be due to the protective effect of chromium and ascorbic acid on pancreatic tissue against oxidative damage, thereby improving the secretion of digestive enzymes. Sahin et al. (2003) observed improved weight gain, feed intake and lower corticosteroid, glucose and malonaldehyde concentrations of birds on supplementation of chromium and ascorbic acid combination.
- Sodium bicarbonate. Sodium bicarbonate can help increase water intake, and reduce systemic acidosis. It can be given through feed instead of drinking water. In vegetarian feed, the inclusion of sodium bicarbonate at 0.4% (4 kilograms per ton) and sodium chloride 0.25%( 2.5 kilograms per ton) would properly balance sodium and chloride levels in feed.
- Betain (osmolyte). When added to feed, Betain (0.5 to 1 gram per ton) helps in maintaining water balance in the body cells against an extracellular osmotic gradient. Electrolytes also have a similar action and are better given through water.
- Antioxidants. During heat stress, there is excessive oxidative metabolism and release of free radicals in the body. Free radicals can damage all types of biological molecules, including cells of vital organs and the immune system. Including Vitamin C in animal feed can help capture and neutralize free radicals. Similarly, antioxidants including BHA, BHT and EQ protect fats and oils in feed from oxidative rancidity.
Birds reject warm water, which can accentuate heat stress. Cool water (10 to 12o C) should be continuously supplied to birds, watering space should be doubled and overhead tanks and pipe systems should be properly covered to keep the water cool. Providing fresh cool water at noon is very effective for internal cooling and reducing symptoms of stress.
Beyond hot weather challenges, other diseases may arise in the summer. Here are precautions to take for disease management in poultry:
- Regularly sanitize drinking water, clean water tanks and flush pipe systems. This can help limit bacterial counts in water, which may be increased with water levels going down in summer.
- Use litter conditioner to maintain litter dryness. Because there is increased intake and excretion of water by birds, litter can become wet and cause ammonia problems in poultry houses.
- Keep vaccinations cold. Carry out vaccinations in cool hours of the day, and ensure vaccines are kept cold during transportation, storage and administration.
- Administer immunostimulants three days after each vaccination.