Introduction One of the main objectives in animal based agricultural research is improving the efficiency of how an animal converts feed into product. It is essential that when considering improving efficiency that animals experiencing environmental stressors are included because their ability to perform has been compromised. One such environmental stressor is heat stress in dairy cattle. Heat stress occurs when an animal exceeds the upper limit of their thermo neutral zone and therefore are using their energy resources to maintain a normal body temperature. The temperature humidity index (THI) is a tool that takes temperature and humidity into account to determine when cows will begin exhibiting symptoms of heat stress. Literature in the …show more content…
2009), however accounts for only 50% of the lost production exhibited when cattle experience heat stress (cite Wheelock and Rhodes 2010). The loss of the other 50% is not clearly defined but evidence suggests that it can be attributed to changes in metabolism of nutrients. Energy metabolism of heat stress dairy cattle has shown to be affected. The response though is opposite of what is seen in animals that are experiencing other forms of negative energy balance. When compared to transition cows that are also in a negative energy balance transition cows have an increase in non-esterified fatty acids (NEFA) levels indicating that adipose tissue is being mobilized (cite). Heat stress cows however do not show this increase in NEFA levels, they have shown an increase insulin. Wheelock et al. 2010 reported an increase in basal insulin of 37%. The increase insulin and absence of an increase in NEFA levels suggests that heat stress animals are not mobilizing their fat stores and are using another source, possibly protein stores in muscle, in order to correct for the negative energy balance. In addition to the increase in basal insulin dairy cattle in heat stress conditions, when administered a glucose tolerance test, exhibited a larger increase (P<0.05) in insulin in response to glucose compared to dairy cattle that were pair fed and housed in thermoneutral conditions (Wheelock et al. 2010). The increase in insulin in response to administering glucose indicates an increase in pancreatic sensitivity. This increase pancreatic sensitivity maybe a metabolic coping mechanism to deal with increased energy demands by trying to maximize glucose
Thyroid and metabolism hormones play a large role in the daily lives of all living species. Thyroid hormones regulate the metabolism and the metabolism is responsible for maintaining a specific range for the biochemical reactions that occur in the body (Martini 2014). The most important hormone for metabolic maintenance is thyroxine (T4). This hormone also plays a large role in body heat regulation. It is produced by the pituitary gland and secreted by the thyroid gland. The thyroid releasing hormone (TRH) must trigger the thyroid stimulating hormones (TSH) to release thyroid hormones to the thyroid gland. These hormones are under control of the hypothalamus, or main neural control center. Propylthiouracil (PTU) is a medication used to treat
Animal metabolism consists of the utilization of nutrients absorbed from the digestive tract and their catabolism as fuel for energy or their conversion into substances of the body. Metabolism is a continuous process because the molecules and even most cells of the body have brief lifetimes and are constantly replaced, while tissue as a whole maintains its characteristic structure. This constant rebuilding process without a net change in the amount of a cell constituent is known as dynamic equilibrium (Grolier1996). In the combustion of food, oxygen is used and carbon dioxide is given off. The rate of oxygen consumption indicates the energy expenditure of an organism, or its metabolic rate (Grolier1996).
Kellems, Richard O., and D. C. Church. Livestock Feeds and Feeding. 6th ed. Boston: Prentice Hall, 2010. Print.
... horses with EMS found that feeding grass hay that was restricted to 1.25% of the animals’ body weights in combination with soaking the feed in cold water and feeding a vitamin and mineral regimen managed to improve the condition of the effected horses. In a period of six weeks, these animals lost an average %BM of about 7% as well as improving in the circumference of their belly and body condition score. Also, the horses showed higher insulin sensitivity by the end of the study.
Normally, cows in Northern Europe in places such as Denmark live normal lives simply grazing on grass, and existing. However, there have been recent changes that have disrupted this normal activity. Generally the bluetongue virus (spread by Culicoides imicola, a biting midge) has been confined to Southern Europe and other places around the Mediterranean. But with the increase in temperature throughout the area, the midge has been allowed to migrate northward. This new pest is a nuisance and causes lots of difficulties to farmers in the area. When a cow contracts this disease, they usually also receive oral ulcers, salivation, stiffness, fever and eventually the inevitable- death (Merck Veterinary Manual NP). Because of the increase in temperature, midges have spread around the globe infecting livestock and creating terrible trouble for many farmers.
The majority of clinical cases of laminitis occur in pastures where there is an accumulation of rapidly fermentable non-structural carbohydrates (NSC) such as fructans, simple sugars or starches (Geor, 2010). Pasture-associated laminitis has major economic and welfare implications in the equine sector. Increased risk factors include insulin resistance, increased insulin secretory response, hypertriglyceridaemia and obesity (Asplin, et al., 2007; Carter, et al., 2009 and de Laat, et al., 2010). Insulin resistance has been associated with a number of problems in the horse, most notably laminitis.
America is one of the world’s largest producers of beef. According to Raloff (2002), approximately 36 million beef cattle are raised in America each year, and approximately two-thirds are treated with hormones (para.2). Farmers use these hormones to increase the rate of growth in their cattle. By increasing the cattle’s growth rate, the farmers can produce more beef and still making more money, they can sell it at an inexpensive rate to the consumers. The hormones that may be administered to beef and dairy cattle may already be produced, in small amounts, naturally in their own bodies or synthetic. According to the U.S. Department of Food and Drug Administration (2002), “the accepted naturally occurring hormones that may be administered to beef and milk producing cattle are estradiol, progesterone, testosterone, and the synthetic hormones that are accepted are zeranol, trenbolone acetate, and melengestrol acetate.” None of the hormones listed above are acceptable in the industries in Europe to give for the food and milk productions.
The horse’s protein requirements vary depending on age and function.
For their body size, goats are slightly more efficient than cows; it takes less feed for a dairy goat to produce a gallon of milk than for a cow to produce a gallon . F...
The differences between conventional and grass-fed beef clearly indicate which beef is a better option. Conventional cattle are crowded into feedlots where each cow is confined and is covered in their own manure. Conventional cattle are also fed corn and soybeans which can cause ulcers and promote an overgrowth of Clostridium perfringens. Antibiotics and hormones are also given to conventional cattle to promote growth and prevent disease. Grass- fed cattle
It all begins with what kind of environment the cow is living in and how it’s being fed, which determines the health of the cattle. In the past when calves are born, they feed off their mother’s milk and later on graze on grass for pretty much the rest of their lives; and in the winter, they would feed on hay. Now in the present, cows are packed into feedlots, get little exercise and practically live in their own manure. Cattle living in this type of situation make them more prone to all sorts of diseases and illnesses. While they are packed in the feedlots, they are fed foods that are high in protein in order to fatten and muscle out the cattle, which causes the cattle to grow and mature at a faster rate. According to Kamb, “In farming communities, a variety of protein sources were readily available, from soybeans or peanuts or cottonseed. Or, from chicken feces, poultry feathers, cow blood or other parts of pigs, hor...
Sweating and Heat Loss Investigation Aim To find out whether heat is lost faster over a sweaty body compared to a dry body. Apparatus 2 Boiling tubes 47ml max 2 Measuring jug 50ml max A Beaker 250ml max 2 thermometers Paper towels A kettle to boil water A stopwatch 2 magnifying glasses (8x) 2 corks with a small hole through the centre A test tube rack Preliminary work In my preliminary work, I need to find out how much water to use, whether the tissue should be wet with hot/cold water, how often the readings should be taken, how accurate should the readings be, how many readings should be taken and what my starting temperature should be. My results are as follows. Starting temperature of 40°c Time (secs) Wet towel (°c) Dry towel (°c) 30 36 38.9 60 35 38.5 90 34 37.9 120 33.9 37.5 150 33 37 180 32.6 36.9 210 32.3 36.8 240 31 36.5 270 30.4 36 300 30.3 35.9 Starting temperature of 65°c Time (secs) Wet towel (°c) Dry towel (°c) 30 51.1 53 60 48.2 51.9 90 46.4 51 120 46 50 150 44.3 49 180 42.9 48.4 210 42.6 46.9 240 41.7 48 270 40.2 47.5 300 39.3 47 Starting temperature of 60°c Time (secs) Wet towel (°c) Dry towel (°c)
Cattle have poor depth perception and because of this they often refuse to cross a shadow or drain gate. “Cattle can distinguish smell and will baulk at the smell of blood and offal” (Currie, 1995). Cow ears are very sensitive but they can be calmed by the sound of soothing music but can also be stressed by yelling or other loud noises. It is found that dairy cows are more sensitive to sound and touch than beef breeds (Lanier et al, 2000). One method used to calm cattle down is cutaneous sensitivity. They like to be scratched in difficult to reach areas such as under the neck and behind the
National Cattlemen's Beef Association, "The Environment and Cattle Production: Fact Sheet”, www.explorebeef.org (accessed Jan. 13, 2011)
According to Health and Safety executive (HSE), (n.d), heat stress is a component of climate change “that causes the body temperature to fail”, and is a global problem which affects agriculture and livestock. The effect of heat stress on Livestock’s has become greater for animals such as dairy cows and beef cattle. When animals are under distress due to temperature rise, they usually cut back on their feeding practices; have a rise in body temperature and faces weight loss. Milk production, milk fat, protein content and the progression of breeding are also affected, especially in dairy cows. When heat stress occurs, dairy cow...