Spring Pastures May Bring Grass Tetany

Submitted by Eileen A. Coite, Livestock Agent for Wayne County

Now that we’ve had some off and on warm days and a good dose of rain, I suspect our winter annuals will take off with spring growth.  With that in mind, it’s always a good time to remember and be cautious of grass tetany, because this is the time we may see symptoms.  Grass tetany is a disorder affecting ruminant animals, specifically cattle, sheep, and goats.  It is also commonly known as magnesium tetany or grass staggers, and most often occurs in nursing females (cows, ewes, or does) during early lactation, especially during late winter and early spring on tall fescue or small grain pastures.  As the name "magnesium tetany" implies, the disorder is a result of low levels of the magnesium mineral in rapidly growing forages, as well as an interference with the absorption of magnesium due to various factors.  Grass tetany is known to be one of the most substantial nutritional problems in grazing livestock, with estimated annual losses of up to $150 million in the US.  

The causes of grass tetany:

Late winter and early spring is time for calving (lambing, or kidding) in many herds.  Because of this, the lactating female requires additional magnesium to offset losses of the mineral through her milk production and urine. Even though the disorder is most often seen in lactating females, stocker cattle may also be affected, especially when grazing small grains. Magnesium requirements are generally greater for lactating animals, and greater for older than for younger animals.   In addition, the pastures many of these animals depend on this time of the year are low in magnesium due to many factors.  Wet soils that are low in oxygen may prevent plants from taking up sufficient levels of magnesium (Mg) regardless of levels in the soil.  Soils that are low in phosphorous, but high in potassium and nitrogen are also a problem, because this tends to counteract the uptake of magnesium.  Generally, forages containing less than .2% magnesium are more likely to cause problems. 

Grass staggers is another name for grass tetany, and for a good reason. Females that show signs of the disorder generally will have a reduced appetite, dull appearance, and stagger when moving.  Other signs include nervousness, frequent urination and defecation, muscle tremors, and excitability, followed by collapse, paddling of the legs and feet, coma, and death. The first sign will often be a dead cow that appeared healthy the last time she was checked. 

Grass tetany can be prevented by feeding ruminants supplemental hay or grain, by fertilizing pastures with dolomitic limestone, which contains magnesium, or by providing a mineral mix or supplement which contains magnesium oxide.  The supplement during these risk periods is the most practical method of prevention.  Supplementing one ounce per day greatly reduces the incidence of the disease.   This can be provided in a home-mixed mineral with 30% magnesium oxide, a commercial "high mag" mineral of 10-14% Mg, or mixed at 6% of a grain mix, fed at one pound/head/day (increase to 2 pounds/head if following an outbreak) If a high mag mineral is used, it should be the only source of salt available in the pasture.  In addition, it's important to monitor the herd and make sure that everyone is getting one ounce/day of the mineral.  Pastures containing legume forages will normally be less affected, because legumes tend to be high in Mg.  Unfortunately, legume growth is often limited in winter months, so this usually won't fix the problem.

To be safe, as mentioned above, it's a good idea to provide additional sources of Mg to your herds in the late winter/early spring when grass tetany can be a problem.  The only way to know for sure if forages are low in Mg is to have them analyzed, which can be done at the NCDA forage testing lab in Raleigh.  Grass tetany isn't hard to prevent, but sure can be devastating to a herd once affected.  

Antibiotic Use in Pork Production

Submitted by Eve H. Honeycutt, Extension Livestock Agent, Lenoir and Greene Counties

Frequently Asked Questions

Concerns have been expressed about the use of antibiotics in pork production.

The National Pork Board supports the use of antibiotics only when they provide demonstrable benefits and has urged producers to:

·      Take appropriate steps to decrease the need for their application;

·      Access the advantages and disadvantages of all uses of antibiotics;

·      Complete the Pork Quality Assurance Program and fully implement the management practices described for responsible use of animal health products into their daily operations.

·      Follow the Take Care responsible use guidelines.

Q    How are antibiotics used in pork production?

 A   Pork producers use antibiotics for three purposes:  to treat illness, to prevent   disease and to improve the nutritional efficiency of their animals.  Antibiotics  can be given by injection of individual animals or delivered through feed or  water.  Producers and their veterinarians use their experience and knowledge in combination with scientific information to decide when to use antibiotics in their pigs.

Q    What is the industry’s position on the use of antibiotics in pork production?

A    The National Pork Board believes it is essential to public health and food safety, animal health and well-being, and the environment to maintain the effectiveness and availability should be based on sound science.  The National Pork Board’s full position on Antibiotic Use in Pork Production can be found online at http://www.pork.org/Pork Science/Documents/PORKSAFETY%fact.pdf.  Additionally, the National Pork Board, through the  Pork Checkoff, launched the Take Care – Use Antibiotics Responsibly program in 2005.  This program helps assure the responsible use of antibiotics by producers. 

Q  Aren’t Antibiotics in Feed only used by large producers?

A  A 2000 survey conducted by the National Animal Health Monitoring System (NAHMS) determined that the use of antibiotics was not related to the size of operation.  In fact, a similar percentage of small producers and large producers report using antibiotics in feed.  More NAHMS information can be found online at   http://www.aphis.usda.gov/vs/ceah/ncahs/nahms/swine/index.htm.

Q: Are there other factors besides

antibiotic use that impact

animal health?

 A: Yes. The use of animal health products,

including antibiotics, is only one part

of a comprehensive herd health program.

Biosecurity, diagnostics, vaccination, facility maintenance and animal care contribute to the farm’s animal health picture.

Q: What is “antibiotic resistance”?

A: “Antibiotic resistance” refers to bacteria that are able to with- stand exposure to antibiotics and, in fact, survive. As is the case with every living organism, bacteria respond to threats in their environ-ment to survive as part of their natural evolution. One such response

is the development of resistance following exposure of the bacteria to antibiotics. Some medical doctors and veterinarians are concerned about antibiotic resistance because it might limit the effectiveness of antibiotics to fight infections.

Q: What else is the industry doing to make sure that resistance doesn’t become a big problem?

A: Pork producers are committed to protecting public health and preserving animal health and well-being by using antibiotics responsibly as outlined in the Take Care – Use Antibiotics Responsibly program. Over 50 million pigs are produced each year by producers who have endorsed this proactive program. We encourage you to learn more about the specifics of the Take Care program by calling (800) 456-PORK or going to pork.org.

Pork.org or the Pork Checkoff Service Center

@ (800) 456-PORK.

Q: Is it safe to use antibiotics in food animals?

A:  Yes. The U.S. Food and Drug Administration (FDA) does not approve the use of antibiotics until they undergo a vigorous review for safety to animals, humans and the environment. The FDA approval process assures food products from animals treated with antibiotics are safe. Pork producers and veterinarians are committed to protecting public health, animal health and animal well-being through the responsible use of antibiotics.

Q: Is the use of antibiotics in farm animals increasing antibiotic resistance in humans?

A: The extent to which antibiotic use in animals actually affects human health is difficult to impossible to measure. We don’t have good, scientifically definitive ways to measure it. However, one panel of experts estimates that 96 percent of antibiotic resistance in humans is due to human use of antibiotics and not transferred from animal uses.

Risk assessments have been conducted on many animal antibiotics to determine the potential  for antimicrobial resistance.  While one can never completely eliminate risk, the assessments determined the risk from using these products was extremely low and the social benefits of using antibiotics outweigh the miniscule risk of antimicrobial resistance.

Q: Would antibiotic resistance in humans end if antibiotic use on

farms was eliminated?

A: No. A recent Institute of Food Technologists’ expert panel report stated that correlating the risk of antibiotic use in animals and antibi- otic resistance in humans is not possible without more research.3 Two key findings include:

•            Meat from livestock raised with and without antibiotic use was shown to contain antibiotic-resistant bacteria.

•            Antibiotic-resistant bacteria develop from many factors including human use of antibiotics and routine household use of disinfec- tants like antibacterial soap. Use of antibiotics in animals is only one small contributing factor in the overall picture.

Q: How do consumers know that the food products they consume are safe?

A: The FDA does not allow the use of antibiotics in farm animals un- til it can prove meat consumed from treated animals is safe. Further, the FDA has mandated a withdrawal time for each antibiotic used. Specifically, food or milk from animals that have been treated with an antibiotic may not enter the food supply until a predetermined amount of time has elapsed since the animal’s last dosage. The withdrawal period is specified for each drug.

Random and on-going samples of meat and milk are tested to ensure adherence to the withdrawal regulations. Samples found to be non- compliant are destroyed and the producer faces stiff penalties.

Q: Isn’t the real issue the use of antibiotics for nutritional efficiency?

A: The appropriate use of antibiotics for treatment, prevention and nutritional efficiency does not negatively impact food safety. There are animal health and societal benefits to using antibiotics to increase nutritional efficiency. Experience in Europe, where the political decision has been made to ban this type of antibiotic use, shows that there is some disease prevention benefit to using antibiotics at nu- tritional efficiency levels. And, even after 8 years, there has been no demonstrated human health benefit to a ban of this type. In addition, animals that convert feed efficiently consume less feed and produce less waste. That means more corn available for the production of renewable fuels and less manure for the producer to manage.

Q: What about organic meats? Are they safer?

A: No. The nutritional and safety profiles of organic meats are not different than conventionally-raised product. Only growing, handling and processing methods differ. There have been many studies that have proven that bacteria, even those resistant to antibiotics, can be found in both types of meat.

 

Getting That New Bull

Submitted By: Emily Herring, Extension Livestock Agent, Pender County

A good way to ensure you are purchasing a good, sound bull would be by making sure a Breeding Soundness Exam (BSE) has been performed.  If one has not been performed on the bull you want to purchase yet you could get a licensed veterinarian to perform the exam.  The BSE will determine the capability of a bull for breeding purposes. A standard BSE will consist of a physical examination, examination of reproductive organs, and evaluation of semen. A bull must pass a normal physical and reproductive exam, have greater than 30% sperm motility, and greater than 70% sperm morphology.  A ’satisfactory’ rating means that the bull has passed all three criteria and is able to service the herd. If the veterinarian was not able to pass the bull on all three guidelines but feels that the bull’s condition may improve with time, he will give a ’deferred’ rating. Then the vet may suggest that you have your bull re-evaluated within 60-80 days to allow enough time for new sperm to be created. An ’unsatisfactory’ bull didn’t pass the BSE and is not suitable for breeding. Breeding soundness exams are usually fairly inexpensive and would strongly recommend one especially if you are using a new or unproven bull.

When thinking about purchasing a new bull, a few things need to be taken into consideration: 

• Look at your herd and establish long-term goals. Evaluate strengths and weaknesses of what you currently have and look for a bull to improve your stock.
• Find a reputable source to purchase from. You are investing in genetics and health that will have an effect on your herd and profit for years to come.
• Pick a bull with enough stature to get your calves in medium grade with good muscling and length. Check feet and legs for structural soundness.
• Expected Progeny Difference, or EPD’s, are a set of numbers that will compare how one bull’s genetics matches up to others of the same breed. These numbers will determine a specific bull’s genetic value on traits like birth weight, weaning weight, and calving ease.
• Select a bull that has either had a breeding soundness exam or is reproductively sound from external appearance. Avoid bulls with a small scrotal circumference or any obvious deformities.

There will be a Breeding Soundness Exam Day held at Harold and Jerry Flanagan's Farm in Farmville, NC on Wednesday March 16 at 9 am.  For more information, call Eve Honeycutt at 252-521-1706 or Jerry Flanagan at 252-341-2697.

Nutrient Requirements for Goats

Submitted by Eve H. Honeycutt

Extension Livestock Agent, Lenoir and Greene Counties

Compiled from the publication, ““Forage Needs and Grazing Management

for Meat Goats in the Humid Southeast” by Luginbuhl, Poore, Mueller, and Green.

The goat is not able to digest the cell walls of plants as well as the cow

because feed stays in their gastrointestinal tract for a shorter time period. A distinction as to what is meant by "poor quality roughage" is necessary in order to make decisions concerning which animal can best utilize a particular forage. Trees and shrubs, which represent poor quality roughage sources for cattle, because of their highly lignified stems and bitter taste, may be adequate in quality for goats. Goats will avoid eating the stems, but don't mind the taste and will benefit from the relatively high levels of protein and cell solubles in the leaves of these plants. On the other hand, straw, which is of poor quality due to high cell wall and low protein, can be used by cattle but will not provide maintenance needs for goats because goats utilize the cell wall even less than cattle.

Goats must consume a more concentrated diet than cattle because their digestive tract size is smaller relative to their maintenance energy needs. When the density of high quality forage is low and the stocking rate is low, goats will still perform well because of their grazing behavior, even though their nutrient requirements exceed those of most domesticated ruminant species. 

High quality forage and/or browse should be available to does during the last month of gestation and to lactating does, to developing/breeding bucks, and to weanlings and yearlings. Female kids needed for reproduction should be grazed with their mothers during as much of the milk feeding period as possible and not weaned early. When the quantity of available forage and/or browse is limited or is of low quality, a concentrate supplement may be considered to maintain desired body condition, depending on cost: benefit. Whole cottonseed makes an excellent supplement for goats when fed at no more than 0.5 lb/head/day. Dry does and non-breeding mature bucks will meet their nutritional requirements on low to medium quality forage (10-12% protein and 50-60% TDN).

Providing free choice a complete goat mineral or a 50:50 mix of trace mineralized salt and dicalcium phosphate is advisable under most situations. Selenium is marginal to deficient in all areas of North Carolina. Therefore, trace mineralized salt or a complete mineral mix containing selenium should always be provided to the goat herd year around. It is sometimes advisable to provide a mineral mix that contains 20-25% magnesium oxide to reduce the risk of grass tetany when heavy milking goats are grazing lush small grain or grass/legume pastures in early lactation. Copper requirements for goats have not been definitively established. Growing and adult goats are less susceptible to copper toxicity than sheep, however, but their tolerance level is not well known. Young, nursing kids are generally more sensitive to copper toxicity than mature goats, and cattle milk replacers should not be fed to nursing kids. Mineral mixes and sweet feed should contain copper carbonate or copper sulfate because these forms of copper are better utilized by the goat than copper oxide.

Suggested Supplemental Feeding Program For Goats

When goats are raised on browse, abundant forage should be made available to allow goats to be very selective and to ingest a high quality diet that will meet their nutritional requirements. When forage or browse is limited or low in protein« 10%), lactating does (and does in the last 30 days of gestation) and developing/breeding bucks should be fed 1.0 Ib/day of a 16% protein mixture (77:20:2.5:0.5 ground corn : soybean meal :goat mineral: limestone). Alternatively, ground corn and soybean meal can be substituted by whole cottonseed for lactating does. Low to medium concentration of protein (> 10%) will meet requirements of dry does and non-breeding bucks. When forage or browse is limited or low in protein ( < 10%), weanlings and yearlings should be fed .5 to 1.0 lb/day of the 16% protein mixture. Goats can be forced to eat very low quality feed including twigs, tree bark, etc., but producers should be aware that this practice will hurt the productivity of superior meat and fiber goats.