Feeds Final

Review of all the old tests + feed additives/toxicology & other random info -> Spring 2024 Dr. Rude

Define Digestion

Define Digestion

the combination of mechanical, chemical, and enzymatic processes occurring in the gastrointestinal tract (GI) that prepares ingested material for absorption by reducing particle size and increasing water solubility

Define Air-Dry Basis

The feedstuff at a 90% dry matter

Define Ration

The amount of a diet consumed by an animal in a 24 hour period

What method of sample collection is best for obtaining a sample of hay for nutrient analysis? Why is it better than the other methods?

Drill core; Best representative sample of all layers of the hay

Which components of proximate analysis tell the lipid and available carbohydrate content of a feed?

Lipid: ether extract

Available CHO: NFE

Describe the procedures required for conducting a digestion trial?

1) Run a proximate analysis on the feed

2) Feed a known amount of feed

3) collect feces

4) Run a proximate analysis on the feces

5) Calculate digestibility —> (intake - excreted) / intake x 100

What time periods are recommended for diet adjustment for cattle and swine before collection data for a trial

Cattle: 8-10 days

Swine: 3-5 days

What are the limiting amino acids in most grain based diets

lysine, methionine, tryptophan, and threonine

What are the benefits of incorporating molasses into feed?

Increase palatability, hide unpalatable ingredients like urea, decreases dustiness, good binder for pellets.

What are the factors that should be considered prior to feeding wet/sprouted grains?

cost, mold, storage

What can be done to increase the feeding value of milo?

Crack, Pop, etc

What information can you give regarding the decision to feed milo regarding its feeding value?

95-98% corn. Changes to 85-90% for ruminants

Identify the guidelines for restricting usage of urea in animal diets. Why would the use of urea be restricted in a diet?

• No more than 1/3 of diet’s Nitrogen

• No more than 1% of diet or 3% of overall concentrate

• No more than 10-15% of protein supplement

• Restricted because too much urea can cause ammonia toxicity and it is not very palatable

What processing must soybean meal be subjected to for appropriate feeding value, and why must this be done?

It must be heated —> anti-trypsin factors

What are the benefits and shortcomings for using fishmeal in a diet?

Benefits: High crude protein, escape value for ruminants

Shortcomings: Product (milk, etc.) will taste fishy

What are the problems with rapeseed meal? What product was developed that eliminated these as probems?

Problems: Eructic acid (causes heart lesions), Myronase enzyme (causes goiters)

Canola oil was developed to eliminate these problems

What is the difference between native and seeded pastures

Native: Naturally occuring, need less than 20 inches rain

Seeded: Man planted, need more than 20 inches of rain

Lespedeza

Developed for the south (heat tolerant).

Annual-quality forage in late summer.

Perennial - sericea-tannin problem

What are forbes and browse?

Forbe: Non grass herb that animals eat (weeds)

Browse: The edible parts of woody vegetation

What is the difference between steam rolling and steam flaking?

Steam Rolled: Short term exposure to heat/steam

Steam Flaked: Long term exposure to heat/steam

Explain the differences among and advantages for high moisture harvesting, reconstituted high moisture grain, and acid preserved high moisture grain

HMH: When animals eat, they eat normal amount but gain more weight, so advantage is improved feed efficiency compared to hay harvested at normal moisture content.

RHM: We harvest at normal moisture content but add moisture later. Feed efficiency is slightly improved, but not like HMH, so less advantage to want to do this.

APHM: Harvest at high moisture and add acetic acid (vinegar) to preserve it. Advantage of having a longer storage period. No mold.

Why is making hay so problematic in the southeast?

For hay to dry, need less than 70% humidity. In the southeast, especially during summer months, the humidity stays much higher than 70%. Hay too wet = mold, hard to store and transport. Also drought during end of summer months. (3/4 points)

What is flushing and why is it done with gilts?

Flushing is when we increase nutrients, specifically energy, prior to breeding gilts. We do this to gilts over sows because sows are already fed to a higher energy diet for lactation. Flushing improves health, increase live embryos, and ovulation rate.

List AND describe the four methods for feed intake restriction for swine discussed in lecture?

1) Individually feed to meet individual needs

2) Feed a high fiber diet so they feel more full, eat less, and don’t act grouchy from being hungry (aka same nutrients but in less feed)

3) Feed an appetite regulator like CaCl at 3.5% or salt

4) Feed every 3 days. Must separate gilts from sows. On the day you feed them, give gilts 24hr access and sows 8hr access

What are the advantages for feeding fat to lactating sows?

Increases piglet’s liver glycogen, adds more fat in colostrum, helps to increase piglet’s survivability, and increases fat in piglets

What are the disadvantages for feeding fat to lactating sows?

Not known to increase piglet birth weight or weaning weight. Also expensive.

Starter diets and whey—what to know

Starter: 3-6wk of age, feed as creep ration. 18-20% CP, contains 10-20% dried whey to enhance digestible CHOs, at least ½ of grain should be corn and add appropriate antibiotics

Whey is high in lactase. Amylase increases throughout growth so they need lactose from the whey as they no longer get milk from mom

Why (or when) are swine diets formulated for amino acid content and not crude protein?

Balancing for AA is cheaper than balancing for crude protein, Usually done by commercial operations. It is more specific to meet the pig’s limiting AA needs (Lysine, Threonine, Methionine, and Tryptophan). Decreases the need for expensive SBM.

What are the advantages to feeding broiler litter to beef cows?

High in CP, easy access/very available in south, inexpensive

What are the disadvantages to feeding broiler litter to beef cows?

Public perception, variable ash content, hard on equipment

What is done to broiler litter before being used as a feed, why and how is this accomplished?

Pathogenic bacteria has to be killed. Accomplish by composting, ensiling (acid fermentation) deepstacking, and heating to 120 F

What is creep feeding in beef cattle?

Feeding an expensive diet to calves for extra nutrients/energy where the cow (mom) cannot access it.

Advantages to creep feeding calves?

Increased weaning weight which brings more $$, decreased weight loss on the cow/mom, minimize stress and shrinkage at weaning

Disadvantages of creep feeding calves?

Expensive, debatable if heifer calves need to since weight gain isn’t earning us $ for replacement heifers

When is NPN best utilized by cattle?

When soluble Nitrogen is low in diet, when it is a low forage diet, when there is lots of access to easy fermented carbs (not cellulose) and when there are low protein needs

When is NPN least used by cattle?

Stressed, high protein requirements, lots of soluble nitrogen in diet (legumes), high forage diet, and low easily fermentable carbs (lots of cellulose)

What are “associative effects” and when is there one with feedlot cattle diets? What can be done to avoid this?

An associative effect is when one feedstuff positively or negatively impacts how an animal uses the nutrients of another in the diet.

In feedlot, a negative associative effect is when you feed calves 60-75% concentrate diet which is too high for them. We can avoid this by 1) preconditioning calves before taking them to the feedlot, 2) using phase feeding → two phase system for 400lb calves where you feed concentrate at 50-60% until they reach 800lbs. one phase system for 800lb+ at 75% concentrate through marketing

How can forage intake be stimulated for dairy cows?

• Feed a variety of forages

• feed multiple times a day

Why are forages important for dairy diets

• stimulate rumen and digestive tract function

• milk fat production → high acetate production from the roughages → why we keep concentrates less than 65% of the diet

When determining the amount of concentrate mixture fed to a dairy cow, what factors need to be considered?

• amount of forages

• lactation requirements of the cow

• composition of milk

What are two things taking place, metabolically, when a ewe has pregnancy toxemia (ketosis). Describe them in detail.

High blood and urine ketone levels

low blood sugar

depleting glycogen reserve

lack of appetite

just giving glucose wont work in ruminants

propylene glycol is the best → use steroids

high producing cow → needs glucose from milk → begins using body fat → acetoacetic acid, B-Hydroxybutyrate, and acetone → ketosis

Cattle prone can be fed high quality before calving and increase substantially after parturition

Describe how dry cows should be nutritionally managed

Feed at 2% DM, feed forages (quality less of concern), 2 weeks before breeding feed high energy, high intake, and low calcium (help prevent milk fever)

Describe the causes of entertoxaemia in sheep

Also called overeating disease or pulpy kidney disease When high amount of readily available carbohydrates are consumed, clostridium perfringens type D is released, toxins thrive and multiply in this environment

Describe the critical periods of feeding for feeding ewes

• Flushing - period 2 weeks before breeding when we increase nutrients, especially energy, to increase ovulation rate

• Last 6 weeks of gestation - growing fetuses, manage for pregnancy toxemia

• First 8 weeks of lactation - feed based on number of lambs

List the methods for preventing milk fever, and provide a disadvantage for each method

1) Low Ca diet 2-3 weeks before calving (Disadv: difficult to find this kind of diet)

2) Vit D prior to calving (Disadv: toxic→ must know exact calving date)

3) decrease DCAD (ratio of cation to anion in diet). (Disadv: salts are not palatable)

What is polioencephalitis and how is it a problem for sheep?

Deficiency of thiamine. When grain diet is overconsumed, bacteria lyses and causes thiaminase enzymes to be released which deplete thiamine levels in the sheep. Causes circling, head pressing, disorientation, blindness, and destroys brain grey matter which leads to death.

Supplement

A feed or feed mixture combined with another feed or feed mixture to provide supplemental nutrients to enhance the animals performance

Diet

The whole bag of feed → the mixture of feedstuffs for many rations (servings) for that animal

Concentrate

A feedstuff that is usually high in energy and contains less than 18% crude fiber. Ex. corn, wheat, soybean meal

Of the components of proximate analysis, which contribute information regarding following content of the feedstuff?

CP

CHO

Minerals

Crude protein: Kjeldahl Nitrogen

Carbohydrate: Crude Fiber and Nitrogen Free Extract

Mineral: Ash

What does TDN stand for and what does it tell about a feedstuff?

Total Digestible Nutrients

Tells us how many lbs of nutrient which we can convert to calories

What is the difference between a marker and an indicator?

Marker: feed a known amount with ration at beginning and end of collection period. (Ideal markers should be: inert, contain no element under investigation, will not diffuse). It tells us the amount of fecal output

Indicator method: similar to marker, but unknown amount fed. just concentration of it in feed. Adv: dont have to collect all of feces → looking for the indicator in a sample of feces. Ex of indicators: chromic oxide, lignin, naturally occurring chromagin compounds.

Apparent Digestibility formula

When converting the % nutrient of feed to be fed from DM basis to as fed basis, does the value increase or decrease?

decrease

What is the most common legume used in livestock diets in the US?

Alfalfa

What is soilage?

(green chop) fresh forage that is cut and chopped in the field then fed to pinned animals (mostly dairies)

Adv: minimize nutrient losses compared to hay, minimize wastage, less fencing, produces maximize yield per acre

Disadv: special equipment, labor, weather related problems for harvesting

What are the most commonly used grains in livestock feeds in the US?

corn, barley, oats, milo

Grinding is the most common processing done to feedstuffs. What is the most commonly used apparatus for grinding?

hammermill

What determines the quality of a protein source?

The amino acids being present in the correct ratio and amount

What are the first steps when balancing a ration?

Determine nutritive value of ingredients

Know how much the animal can eat (intake) and what nutrients the animal requires

Convert to an air dry basis (90%)

When balancing a ration, the units for animal rquirements should always be in which form?

Amount needed on a daily basis

If a diet is deficient in the following, which feedstuffs are you to use to meet the requirements?

Ca:

Ca & P:

Ca: Limestone

Ca & P: Limestone and Dicalcium Phosphate

If you are going to substitute tankage meal (50% CP) for cow peas (20% CP), what is your NET increase in protein?

50-20 = 30%

What is free choice feeding? What is a disadvantage of using this method of feeding?

Free choice feeding the pig has access to feed 24/7 but in separate bowls of ingredients (high moisture corn in one bowl, other ingredients in another). Disadvantage: pigs will eat more of one bowl than another

What are the difference between a grower diet and a finisher diet for pigs?

Grower: 14-16% CP, usually fed from 40-120lb, focused on gaining muscle

finisher: 12-14% CP, fed 120lb-market, focused on gaining fat for consumer

What are two concerns when using whole soybeans in swine diets?

Antitrypsin factor denatured by heat

Low protein

When are the critical 100 days for nutrionally managing cows?

The critical 100 days for nutritionally managing cows is 30 days before calving and 70 days after calving

What is necessary for pre-conditional calves?

Preconditioning: preparing calves for feedlot adaptation before it leaves the production site.

Necessary: Wean and start on grain at least 1 month prior to sale. Adjust to feed bunks and water troughs. Feed a diet similar to feedlot. Castrate, dehorn, and treat for grubs/worms no less than 3 weeks before sale. Vaccinate for IBR, parainfluenza, pastruella spp., and clostridial spp. 3 weeks before sale.

Optimal: Vaccinate for leptospirosis, bovine viral diarrhea (BVD), and bovine respiratory disease

What proportional body weight should heifers be at breeding?

60-65% of mature weight by breeding at 15 months

What is usually the most (first) limiting nutrional factor in sheep diets?

energy

Why is optimal production preferred in sheep rather than maximum?

At max production, we get extra fat deposition which is a bad flavor and texture to consumers in the US. It is also not efficient or economical to max production and can lead to nutritional disorders for the sheep.

What is the specific bacteria which causes entertoxaemia in sheep?

Clostridium Perfingens Type D

What factors dictate the feedstuffs used in the concentrate fed to a dairy cow?

Cost, availability, and what forage is being fed (if forage is high in protein then feed low protein concentrate and vice-versa)

As presented in lecture, what are the “types” of protein in a dairy ration?

True protein and NPN

If a dairy ration has a UFP of +5, what can be done to the ration?

UFP: Urea Fermentation Potential

If a dairy ration has a UFP of +5, it means that 5 grams of urea/kg of DM can be converted to microbial protein

This value is dependent upon the energy in the diet. A negative value indicates no protein would be synthesized with the energy available.

What can be done to prevent ketosis in dairy cattle?

Cattle prone can be fed high quality before calving & increase substantially after parturition

Why are concentrates limited to less than 65% of dairy diets?

Concentrates are limited to less than 65% because if they are greater than 65% it will affect the breakdown of VFAs which will interfere in milk production (acetate is important for milk fat)

What do ruminal microbes need to make microbial protein?

Carbon skeleton, Nitrogen, and energy

Energy formulas

What are the two types of grinders for feedstuffs?

Hammermill and Burrmill

How to make a pellet

Heat, pressure, and moisture

Carbonaceous concentrates are fed for…

energy

Proteinaceous concentrates are fed for…

protein

First rule of toxicology

Everything is toxic in improper amount, dose, frequency, and duration

Chemical name for fungi that grows on bahia, rye, barley, and dallisgrass

Ergot

Ergot symptoms

staggers in cattle, vasoconstriction, gangrene, high BP

most common ergot source

dallisgrass

How to treat ergot toxicity

remove it

Fescue toxicity is caused by:

endophytic fungus in the seed

Symptoms of fescue toxicity in horses

Hoof and tail tip slough off, abortions, agalactia (decreased milk prod), increased gestation length

Symptoms of fescue toxicity for every animal

Decreased ADG, decreased feed intake → side effects of having a high body temp

How to prevent fescue toxicity:

feed genetically modified fescue that is free of the toxin

Drugs (doesn’t work very well)

graze to decrease seed production

Slaframine causes what

slobbers (high slobber and diarrhea) and can lead to bloat

Slaframine is in what grasses?

red and white clover

Sweet clover poisoning is tied to…

dicoumarol (brand name: warfarin) which blocks the function of vit K so blood can’t clot

Cyanide poisoning is associated with what blood color?

Bright red

Nitrate poisoning is associated with what color blood?

chocolate brown

Cyanide poisoning explained:

Electron transport stops, no energy is converted, blood will have high amount of oxygen which is where the red color comes from. Water speeds this up.

Cyanide poisoning is from what plants?

Sorghums (J Grass, Milo, etc.) and choke cherries

Nitrate poisoning explained

Nitrate gets reduced to nitrite, the nitrite binds irreversibly with hemoglobin to form methemoglobin which causes anoxia (no oxygen) so no oxygen. Once bound, it cant be unbound. No oxygen = chocolate color blood