Livestock

Ash can trash your forage value

Written by Dr. Jim White on .

When reviewing the numbers on a forage analysis, most producers pay close attention to the crude protein and fiber levels of hay they’re feeding to their livestock. But are you checking the ash?

The ash content in harvested forages can have a significant role in animal performance. In the lab, the amount of ash in a forage sample is determined by burning off the organic material and weighing the residue that is left. Much of the ash will be made up of minerals, such as phosphorus, potassium, calcium, magnesium and others. These minerals are essential for both plants and livestock.

However, a potentially large fraction of ash in the feed can be from soil contamination. This shows up principally as silica, which is not digested by the animals. Silica isn’t necessarily detrimental, but it does dilute the nutrient content and contributes nothing to feed value. Ash takes the place of nutrients on approximately a 1-to-1 basis. Further, added ash can bring greater mold and yeast counts, which are soil-borne organisms.

High forage ash content is consistent with drought, dry weather and dusty conditions as well as flooding, wet soils and mud. Heavy rains have the potential to splash soil particles onto forage. Rodents, gravel roads and aerobic deterioration have also been associated with higher ash values.

Looking at large numbers of samples from the lab, we see the ash content range from 5 to 18 percent. Values trend in the lower end of that range for grasses and haylage. The objective is to keep external soil contamination below 3 percent of the mass, which roughly means the forage should test under 11 percent ash. Values above that represent external sources and are negatively associated with forage quality and animal performance.

The way forage is harvested can increase the external component of forage ash content. A June 2017 article in Hay and Forage Grower offers these management practices that can minimize ash percentage:

  1. Consider different cutting height. Though a low cutting height offers more yield potential, it also results in more soil being incorporated into the forage. A cutting height of 3 inches for alfalfa and 4 inches for grass is a good compromise.
  2. Make wide swaths. This will not only speed the drying rate but also keep the wilting forage on top of the stubble and off the ground.
  3. Use flat knives on disc mowers. These create less suction and introduce less soil into the forage than angled knives.
  4. A mower’s cutterbar setting affects the amount of dirt pulled into the cut crop. Be sure to keep the angle of the cutterbar as flat as possible. If the cutterbar is tipped too far forward, it will force the knives to scalp the soil surface.
  5. Make sure rakes and tedders are properly adjusted and maintained. The goal is to move forage, not the soil. This is easiest when the tines are adjusted so they barely touch the ground, where they will hit a sheet of paper, but not scrape dirt.
  6. Rake as little as possible. Often hay has to be raked, but use strategies that minimize hay movement over the ground. Mergers are much more effective in this regard as the hay is actually picked up before being moved. The forage mat should be flipped, with the intent of allowing sunlight to hit earlier shaded material.
  7. Widening the swath or windrow can reduce the ash level. Packing all of the cut crop into a narrow, heavy windrow usually causes it to sink through the stubble and sit directly on the ground. A wider swath will spread the weight of the cut crop across a larger surface area, helping it sit on top of the stubble.
  8. Control rodents. In addition to the damage they do to fields and plants, their dirt mounds are easily incorporated into forage windrows.
  9. Keep storage areas clean. Dirt can be added at the storage and loading site as easily as in the field. Keep silage bags and silo piles on well-drained, solid surfaces.

It is important to note that the sum of minerals on most forage reports is not total ash content because mineral analysis usually does not include silica, which is the largest proportion of ash. So look for an “ash” value on the report. The greater attention to ash content has now led many forage laboratories to offer a neutral detergent fiber (NDF) analysis that is ash-free. This is designated as NDFom or aNDFom on the forage analysis report. For samples with low ash, the NDF and the NDFom will be similar.

Raising dairy heifers to their highest potential

Written by Dr. Jim White on .

Producers who are successful in raising heifers follow similar management practices. They feed high-quality feedstuffs and don’t feed too much forage too soon. They feed to maximize animal productivity. They have good records on animal performance and health.

One of the most important factors is avoiding the post-weaning lag. Some producers observe diminishing animal performance when calves are moved from hutches to group pens. Calves that are eating 2 pounds of starter feed a day often will fall behind when moved to the group housing, but those eating 6 pounds do not. Waiting for a couple of weeks to introduce hay to group-housed calves is usually helpful. The rumen won’t be fully developed until the calves are 400-450 pounds, so they will be 4-6 months old before the rumen is large enough and developed enough to handle a diet high in forage. Forage quality and availability need to be adequate. Clean, fresh water needs to always be available.

Group size can be a factor. Smaller groups mean fewer friends to deal with and usually cause less stress. Providing adequate shelter also helps. Protecting calves from weather extremes reduces their feed needs and improves performance. Calves will lay down in a dry, draft-free, well-bedded area, if available. Ambient temperature, moisture, hair coat and wind directly influence the calves’ nutrient needs. This is a winter time concern as well as a summer concern.

From the time heifer calves are weaned until they reach about 450 pounds is not the time to skimp on feed quality. They can gain 2.5 pounds a day and have been shown to have better lactation performance when provided adequate amounts of quality rations. The principle of “that which is cheapest wins” is always a temptation, but reducing ration costs doesn’t need to come at the cost of animal performance. For example, if I feed too much forage to small calves, their average daily gain (ADG) drops. When I divide the daily feed cost by a smaller amount of gain, I often see an increase in cost of gain. That will get a nutritionist fired.

Pre-weaning starter feeds, such as MFA StandOut, and grower feeds, such as MFA Trendsetter, will have:

  • Palatable and digestible sources of protein, proving adequate metabolizable protein
  • Adequate energy
  • Vitamins and minerals
  • Refined functional carbohydrates
  • Appropriate feed additives, e.g. Rumensin, Shield Technology

Adequate heifer growth means heifers achieve height and weight goals. They should be ready for breeding at the targeted time. Moving heifers to the breeding group should be based on weight and hip height, rather than age. The current recommendation is to breed heifers at about 55 percent of the dam’s mature bodyweight.

Holsteins should be 51 to 52 inches at the hip and 750 pounds before being put in the breeding group. Jerseys are smaller and should be 40 inches at the hip and 600 pounds. Even though we see some heifers—one out of every five or six—start to cycle at 9 months of age, it is recommended to not breed heifers younger than 10 months.

The ADG objective of a bred heifer is about 1.75 pounds per day. If we feed high-energy diets—particularly if the diet is high energy and low in protein, such as high-yield corn silage or a feedlot type diet—the heifers will get fat. This is particularly detrimental. With these types of feedstuffs, heifers may need their feed restricted. Feeding about 85 percent of free-choice intake achieves the performance goals but does not over-condition them. For bred heifers on a grass forage base, I tend to see 66 to 85 percent of the diet as forage.

Holstein heifers should be eating about 22 pounds of dry matter a day when they are ready to calve; Jersey heifers will be eating about 17 pounds. The preference is to have heifers on the close-up diet the last month of pregnancy. The close-up diet should be more concentrated than the grower diet. At the end of pregnancy, the fetal tissue and mammary gland are soaking up a lot of nutrients. The heifer has continued nutrient needs for growth and maintenance. Her dry matter intake declines as calving approaches. If she can’t eat enough to meet the energy and protein need, she will start to mobilize muscle and fat. This is not good. Excessive weight loss predisposes the animal to fatty liver. Ensure the diet is adequate.

Effective electrolytes can be the solution for scours

Written by Dr. Jim White on .

Calf scours is one of the most important and costly calf health issues affecting dairy operations in North America. According to the USDA, scours, diarrhea and other digestive problems are responsible for more than half of all pre-weaned heifer calf deaths. The National Animal Health Monitoring Survey attributes six in 10 deaths of calves under the age of 2 months to calf scours. Calves that scour in the first 14 days of life are at a higher risk for mortality due to secondary infection during the first 90 days of life.

Calf scours is caused by any number of micro-organisms, ranging from viruses, such as rotavirus or coronavirus, to bacteria, such as E. coli, salmonella or protozoa. Scours can also be incited by nutritional challenges, including changing dietary inputs, unpasteurized waste milk, transport and vaccinations. Climatic factors such as wet environments, freezing temperatures and wind chill make calves particularly susceptible.

Whatever the cause, scours severely dehydrates newborn calves, whose bodyweight is around 70-percent water. Calves can lose 5 to 10 percent of their bodyweight in water within a single day of scouring. More than 14 percent loss of water can cause death.

Unfortunately, once a calf starts scouring, replacing lost fluids is not enough. An effective oral rehydration program must give the calf sufficient amounts of fluids, offer an effective solution for correcting acid-base balance and provide nutrition.

While dehydration significantly contributes to the overall poor condition of calves, it must be noted calves with diarrhea die from:

  1. Acidosis  
  2. Septicemia
  3. Hyperkalemia
  4. Hypoglycemia  
  5. Hypothermia

Electrolytes provided to scouring calves not only need to drive the rehydration of the calves but must also address the associated conditions.

An important concern for treatment of scours is the acidic nature of the blood caused by dehydration. Calves that suffer moderate to severe acidosis are less apt to eat and drink on a free-choice basis. Providing alkalinizing agents early on to scouring calves is paramount in their survival from a scour-causing infection. The challenge is that those same life-saving alkalinizing agents aren’t palatable. Thus, treatment of scours with an oral electrolyte solution must be done in tandem with our knowledge of calf behavior. To rehydrate calves and minimize on-farm labor requirements, calves must willingly drink an electrolyte solution, and it’s our job to provide a flavor, taste and formula calves will find appealing.

Be sure to detect dehydration early and correctly and ensure consistency in how the product is delivered. The industry has thought about electrolytes largely one way: dry powders. Arguably, the dry powders acted as a hindrance in providing the calf with all the critical nutrients it needs to recover from scours.

Scouring calves need fluid therapy, but what that fluid delivers can be the difference between life and death. Proper rehydration results from the supply of key nutrients at the proper concentration with the right alkalinizing agents to keep your animals drinking, eating and producing.

Characteristics of an effective oral electrolyte include:

  • Sufficient sodium to replace fluids and restore blood flow. The optimal concentration is 90 to 130 mM (millimolar, a unit of concentration of a solution) per liter.
  • Supplemental electrolytes such as potassium, which should be at 10 to 30 mM per liter, and chloride should be at 40 to 80 mM per liter.
  • An excess of strong cations such as sodium, potassium, calcium, magnesium compared to the concentration of strong anions—chloride, bicarbonate, D-lactate.
  • Neutral amino acids and/or fatty acids such as glycine, acetate or propionate to encourage absorption of the sodium and fluids in the intestine.
  • Alkalinizing agents such as acetate or propionate to correct an acidotic blood pH.
  • Non-milk energy sources to provide energy to hypoglycemic calves.
  • Particle concentration to provide additional energy for scouring calves not receiving milk. The optimal concentration of 600 mOsm/L (milliosmoles per liter, which measures solute particles contained in a solution).

Work with your veterinarian and nutritionist to develop protocols for treating calf scours, including the use of an effective electrolyte supplement.

Give cattle a break

Written by Dr. Jim White on .

Earlier in my life, I lived on the Iowa-Minnesota-Dakota border. Up there, snow is part of the economy, and we would get aggressive about dealing with it. Here in Missouri, people tell me, “God put the snow here, and he will get rid of it, too.” But coming from the North, I know that God is OK with snow in June. That snow needs to go.

When it comes to managing cattle in the winter, one way to reduce cold stress is to ensure they have a windbreak or shelter belt. This provides both protection and snow management. Mitigating the effects of wind chill helps reduce feed needs, illness, stress and health costs. We also see better gains in calves and improved body condition in cows. Windbreaks are particularly helpful to calving and young animals.

Natural shelter belts may have trees that don’t have much foliage in the winter and early spring to stop wind. If you plant a shelter belt, use two rows of tall trees and two rows of smaller trees. For the most protection, include conifers. (I am channeling my inner Norskie.)

If building a windbreak with boards, use vertical 2x4s with a 0.75-inch to 1-inch gap between them for an 80-percent solid structure. You can also use rigid rib steel sheets that are 30 inches wide. These are wide enough for calves to hide behind. When placed 36 inches on center, they have adequate gap, and they go up fast. Windbreaks made with slabs are cheap and work well for this application.

If the windbreak is less than 65-percent solid, then you start to lose the sheltering effect. There’s more air coming through rather than being pushed up and over. You want to create a dead zone for the air to protect the cattle. A stream is a good example. If there is a rock in the stream, the water goes around the rock. Right behind the rock, there is an “eddy,” an area where there is still water. This is how you get turned around in your canoe on a river. You nose the craft around the rock, put it into the eddy and the current pushes the stern faster, turning you around.

A solid windbreak is not the first choice, either. It reduces wind speed right next to the windbreak, and snow will dump against it. This reduces the protected area for cattle to bed or stand behind. It is better to have a porous windbreak that is 70 to 80 percent solid. The protected zone behind a windbreak extends 10 to 20 times its height. For example, a 10-foot-tall fence slows the wind for about 100 to 150 feet behind it. If it is a straight windbreak, and the wind is coming head on, this creates a triangular protected zone.

It’s a double whammy if cattle get wet. Their critical temperature is higher, and wind magnifies the cold stress. A dry winter hair coat is good insulation against the cold. When the hair is standing up, fluffy with air spaces between the hairs, the insulation effect is substantial. However, wet hair is flat and changes the cow’s thermal neutral zone. Wet winter hair has the same insulation capacity as summer hair. That is, cattle will get cold at 60 degrees when wet.

Some of the coldest days for cattle are when the temperature may be higher but it’s wet. In the Atlas storm of October 2013 in the Dakotas, a substantial number of cattle died. The reason for the mortality was that it rained first and then got cold. The cattle had wet hides and were unable to stay warm. It didn’t get really cold, just cold enough they couldn’t maintain body heat without that insulation. They were chilled too much for too long.

Bottom line, if you can keep cattle dry and out of the wind during the winter, it will improve their health and well-being. Windbreaks can be part of the solution.

Watering in a winter wonderland

Written by Dr. Jim White on .

The hot, dry days of summer may be when proper hydration seems to be most essential to livestock, but the truth is that winter watering is just as critical. Those cold, blustery days when you most want to stay inside by the fire are the days it pays to watch your water.

Just like essential minerals, water adds zero energy to the diet, yet it is critical for survival and exploiting the nutritional value of feed. And no matter how much snow is on the ground, it is not an adequate water source for livestock.

Among cattle, the water-drinking champs are wet milk cows. A high-producing cow might suck down 25 gallons of water a day. It’s common to see cows drink three times the weight of feed in the form of water. The requisite volume of water needed is often an afterthought, particularly in the winter. True, water requirement is reduced in the winter, but it remains substantial.

Adequate water intake is necessary for:
•    Transporting nutrients and excretions.
•    Chemical reactions and its solvent properties.
•    Regulating body temperature.
•    Maintaining shape of body cells.
•    Lubricating and cushioning joints and organs.

Lack of water has serious consequences, including reduced feed intake, lower productivity, weight loss due to dehydration and increased excretion of nitrogen and electrolytes such as sodium and potassium. Serious dehydration can even lead to death.

Ensure adequate water availability at all times to maintain hydration and normal metabolic activity. Some things can reduce water intake, even when availability is adequate. Check and monitor water intake regularly. In fact, evaluate water consumption as closely as you calculate dry matter consumption—it is that important. If water intake is less than expected and availability is good, then determine if there is anything that may be decreasing the water’s palatability. Cattle have a keener sense of smell than humans. Physiochemical factors that have been shown to influence water intake include total dissolved solids; sulfur, sulfate, sulfite and sulfide; chloride; iron; nitrate; manganese and fluoride. Water may also harbor pathogenic bacteria such as salmonella.

In addition, poor water quality can cause problems with facilities and equipment. For example, dissolved solids can cause water flow and waterer challenges. High iron might permit iron bacteria to grow, plugging water lines and systems.
Follow good management practices by flushing and cleaning waterers routinely. Feed, fecal bacteria and water-borne contaminants should be regularly cleaned out. Water quality in wells may be inconsistent. Mineral levels and total dissolved solids may fluctuate during the year.

If you suspect water quality is an issue, start with a livestock water analysis. You may need to treat the water with a shock treatment, filters, reverse osmosis or other means. More drastically, you may need a new well or switch to using municipal or rural utility water.

All water from natural sources contains impurities. Some of these impurities adversely affect the usefulness and suitability of water, while others may improve its palatability. Pure water is tasteless, colorless and odorless. It also feels slick on the skin. Because pure water is one of the best solvents available, it picks up impurities easily. Water may be cleansed or polluted as it flows over or filters through soil or other material. It may pick up or lose bacteria and dissolve or lose chemicals, minerals and sediment. The belief that flowing or soil-filtered water has purified itself is false and leads to an unjustified feeling about water safety. Clear water is not necessarily safe, just as colored or turbid water is not necessarily unsafe.

Water that is safe to drink is not necessarily nice to drink. To ensure livestock stay properly hydrated year round, make sure their water source is both safe and palatable.

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