5. Nutritional and Metabolic Diseases

1. Forages: Energy, Protein, Fiber
a. Hay - Grass or Legume
Grass hay usually lower in protein than legume (alfalfa = lucerne) hay
Goats more selective than sheep, will pick out best parts - eat leaves but not stems
Forage analysis for goats requires analysis of hay as fed and of what remains in manger.
Off 10-25% extra roughage to maximize consumption.

b. Silage
Often higher in protein because cut earlier in growth phase (weather considerations)
Goats can pick out corn kernels from leaves/stalks
Poor quality silage with pH > 5 or dirt mixed in is risk of listeriosis

c. Root Crops
British feed turnips - easy to stockpile in field
Require good incisor teeth!

d. Pasture and Browse
Goats prefer shrubs and tree leaves to grass
Higher mineral content - goats seem to need more minerals in their diet than sheep
Goats can survive in dry period by climbing trees and eating leaves.
Goats blamed for deforestation
Many garden/ornamental shrubs are toxic (Rhododendron, Taxus)
Very good (lush) pasture often supports more parasites - frequent pasture rotation may be necessary.
 Alternate grazing with harvesting hay or silage.
 Grazing sheep with goats or with cattle increases use of pasture plants.
 Exposure to abomasal and intestinal parasites and to paratuberculosis may increase with mixed grazing.

e. Requirements for Activity
Animals on pasture need more energy and protein than those kept in barn
At least 20-25% more if light grazing, more if long distances.

f. Requirements for Growth
Protein requirements higher for younger animals
20-30% protein in milk replacer (kid - lamb)
Feed ewe 500 g grain /day for each lamb being raised
Group ewes according to how many lambs they are raising, provide adequate trough space for all to eat.
Delay weaning of goat kids until 9 kg, or else get growth setback
Large lambs and kids get more parasites than nutrition from their mothers ? wean to clean pasture.
Weaned goat kids fed 500g grain/day to allow breeding at 7-8 months of age.

g. Requirements for Milk Production
Better quality forage.  Also need more salt.
As with dairy cows, 17% protein in total diet.
Feeding more concentrate (grain) risks indigestion
Maximum 1 kg grain at a meal.
Feed lactating ewes 500 g concentrate per lamb being raised per day.
Could feed 3 meals a day to high producers, but rumen stays healthier with better forage.

2. Water and Minerals
a. Water
Desert breeds of goats can survive 4 days between drinks.
Non lactating animals on good pasture get enough water from grass and dew.
Otherwise need clean water ad lib.
Prevent freezing of water supply in winter.

b. Salt with Trace Minerals
Because animals consume NaCl according to their requirements, other trace minerals can be mixed with NaCl to regulate consumption.
Loose salt is consumed more readily than a salt block
Usually need to supply on pasture as well as in the barn.

c. Iodine Deficiency - Goiter
Some geographic regions, including southern Germany, northeastern USA, Himalayan mountains, are deficient in iodine.  If the grain or mineralized salt is not supplemented, abortions, weak lambs and kids, poor haircoat, and goiters occur.  Growth and fertility are reduced.  Normal requirements are 0.8 ppm dry matter in lactating females and 0.2 ppm for others.  The requirement increases ( to 2 ppm in lactating goats) if plants of the Brassica genus are fed.
Rapidly growing lambs and kids (especially Nubians) sometimes develop a swelling in the neck in the region of the thyroid gland.  This ectopic thymus begins to decrease in size after 2 months of age.
Thymus often remains in the thorax of adult goats; thymoma is a common neoplasm of older goats.

d. Vitamin E - Selenium
Deficiency of one or both of these antioxidants can result in nutritional muscular dystrophy ("white muscle disease"), retained placenta, poor haircoat with dry scales, and reduced immune response.
Deficiency occurs when the soil is deficient in selenium, and when the ration is based on silage or old hay.  Supplementation on a daily basis in the concentrate or salt is better than injections.
In problem herds, vitamin E/selenium injections are often given at birth and at one month of age, as little selenium in found in the milk.
Rapidly growing animals develop white muscle disease, with stiff limbs or heart failure (often sudden death) or inhalation pneumonia.

e. Zinc Deficiency
Excess calcium in the diet interferes with zinc absorption.
Major signs of zinc deficiency are skin crusts (parakeratosis) especially on the coronary bands and around the eyes, salivation, and reduced fertility, especially in male sheep and goats.

f. Copper Toxicity
Common in sheep, rare in goats.  Goats need more copper than sheep do!
Excessive copper or too little molybdenum allows copper to accumulate in the liver.  At a time of stress, the copper is suddenly released from the liver and causes a hemolytic crisis. The sheep is off feed and stands with arched back (kidney pain).  All tissues, including the sclera and internal fat, are yellow (icterus) to brownish if methemoglobin also present.  The liver is swollen and orange.  Urine is dark (coffee colored) because of hemoglobinuria and the kidneys are bronze/black with severe nephrosis..
Treatment of clinical cases is rarely successful (ammonium molybdate, sodium sulfate, penicillamine) but correct diet and treat remainder of herd with oral ammonium molybdate and sodium sulfate for 3 weeks.

g. Copper Deficiency
See lecture of 5.7.00
inadequate copper or excess molybdenum
congenital form: uncoordinated from birth, head tremor, nystagmus, opisthotonos, unable to suckle,
 may be stillborn
delayed swayback appears when several weeks or months old; hind limbs sway, spinal cord
demyelination, chromatolysis of neurons in ventral horns - irreversible
non-neurologic signs include loss of wool crimp, depigmentation, anemia, illthrift, diarrhea,
osteoporosis, low fertility

h. Cobalt Deficiency
A component of vitamin B12, necessary for rumen microbes to make this vitamin.
Signs of deficiency include poor appetite and production, weight loss, weakness, anemia.
Diarrhea common, related to disturbed digestive flora and increased susceptibility to parasites.
White liver disease = hepatic lipodystrophy in lambs, because of disruption to carbohydrate metabolism.

3. Differentials for Nutritional Deficiencies - see lectures of 3.7.00 and 4.7.00
a. Starvation versus Parasitism
b. Liver Flukes
c. Coccidiosis in lambs and kids, especially under 6 months of age.
d. Paratuberculosis, Internal Caseous Lymphadenitis, CAE
e. Social Hierarchy and Tooth Problems

4. Pregnancy Toxemia
a. Pathogenesis
Increased energy demands in last 6 weeks of pregnancy.
Dry matter intake decreases as uterus enlarges.
Problems if twins (or more) and overly fat ("estate ketosis") or under fed ("starvation ketosis")

b. Clinical Signs
Depressed, off feed, separates from group.  May grind teeth or appear blind. Scanty feces.  Ketones in urine.  Eventually unable to rise.  Toxemia when fetuses die.

c. Treatment
Early case - glucose IV, B vitamins, 60 ml propylene glycol 2 to 3 times a day orally, increased energy in feed.
More severe cases need more intravenous fluids (5 liters) with sodium bicarbonate, dexamethasone, some give insulin.
Severe case needs cesarean section.  Response to hormonal induction will be too slow.  Might delay cesarean overnight to allow corticosteroids to prepare fetal lungs (surfactant).  If animal does not react to needle used for local anesthesia, prognosis for survival of mother or lambs/kids is poor.

d. Prevention
Do not allow animals to become obese before or during pregnancy.  Increase grain to 500 g (to 1 kg) in late pregnancy.  If know number of fetuses from ultrasound, feed according to singles versus twins versus triplets.
Avoid any management practice that puts late pregnant animals off feed, including overfeeding grain.

5. Hypocalcemia
Muscle weakness and collapse, often with head stretched out on the ground and hindlimbs extending behind the sheep.  Often resembles severe pneumonia.
Occurs in late pregnancy (especially if increased exercise from forced walking or dog attack) or lactating animals.  At time of parturition, weakened uterus may delay delivery of fetuses or placenta.
Goats may collapse acutely with very low blood calcium values at 1 to 3 or 4 weeks after parturition.  Some of these animals have been fed excessive grain.
Treat with slow intravenous infusion of calcium; may supplement with calcium subcutaneously

6. Disturbances of Rumen Function, Grain Overload
a. Enterotoxemia - see lecture of 5.7.00
Excess carbohydrates in the diet reach the small intestine.  Here Clostridium perfringens type D, normally present, overgrows and produces the epsilon toxin that causes acute collapse and death in unvaccinated animals.
Goats also have a chronic form with recurrent dullness, decreased appetite and production, diarrhea, and weight loss.  Oral sulfonamides may help to treat these animals.

b. Mild Indigestion
Avoid any sudden change in amount or quality of grain or forage.

c. Rumen Acidosis, Lactic Acidosis
Excess grain in unadapted rumen digested to release more volatile fatty acids than can be absorbed.  This permits overgrowth of Streptococci, which produce more acid and as pH drops Lactobacilli take over.  When pH drops below 5.5, difficult for rumen to correct with just saliva and hay diet.
Animal becomes dehydrated as fluid pulled into the rumen, which becomes splashy.  Sample rumen fluid with sound or needle to check pH and verify overgrowth of gram positive cocci and rods.
Treat with IV fluids, bicarbonate, B vitamins.  Oral oxytetracyline - one dose of 500 mg.

d. Polioencephalomalacia - see lecture of 5.7.00
Blindness, nystagmus, dorsomedial strabismus, eventual convulsions.
Upset of rumen flora leads to thiamine deficiency.
May follow apparent milk indigestion with diarrhea.
Treat with thiamine 10 mg/kg three times a day.
Outer layers of cerebrum fluoresce under ultraviolet light.

7. Urolithiasis
a. Anatomy
A problem only for the male and castrated male.
Urethral process extends beyond glans penis, unless animal was castrated before puberty and
adhesions to prepuce remain.
Urethral process is narrowest part of the urethra.
Urethra also constricted at sigmoid flexure.
Urethral recess (diverticulum) prevents catheterization of the bladder.

b. Clinical Signs
Very common in pet pygmy goats in USA.
Acute case - abdominal pain, off feed, straining to urinate ("constipation"), pulsation of urethra.
If obstruction incomplete, dribbles bloody urine, maybe crystals on prepuce.
If  urethra ruptures, swelling of  prepuce and subcutaneously over ventral abdomen ? "water belly"
If bladder ruptures (at apex), straining may stop but animal becomes more depressed.
Fluid wave in distended abdomen.
Bad odor to breath

c. Examination
Any male or castrated male sheep or goat that is off feed or depressed or straining as if to urinate or
defecate is presumed to be obstructed until seen to urinate!
A completely obstructed animal may eat briefly after transport to the clinic.
Creatinine is better blood test for obstruction than serum urea, as long as rumen still functioning to
metabolize urea.
Set animal up on its rump, with upper body slightly forward of vertical ? sheep easier than goat.
Alternate position is with the animal on its back, hind feet pulled forward to the ears.
Avoid xylazine if possible - cleared through the urine.
Penis easily exteriorized from prepuce if mature, intact male.
May see accumulation of "sand" or distinct calculus (round and brass colored if calcium carbonate) in
urethral process.
May be impossible to exteriorize penis in fat wether, castrated before puberty.
Ultrasound for size of bladder, free abdominal fluid. - or abdominal centesis lateral to prepuce.
Animal that is not obstructed will often urinate after examination and blood sampling.

d. Surgical Correction
If obstruction in urethral process, amputate with scissors and give anti-inflammatory or muscle relaxing drug.
Usually multiple calculi remain in bladder, so give urinary acidifier (ammonium chloride).
Sometimes can pass catheter part way into urethra and flush out calculi, but must first cut off urethral process.  Still have problem of more calculi in bladder.
Perineal urethrostomy under epidural anesthesia is quick to do but opening usually constricts closed in a few months ? not satisfactory for pet animal.
Cystotomy to remove all calculi from bladder and placement of mushroom catheter for several weeks while calculi in urethra dissolve and urethra heals is preferred treatment.
Surgeons now experimenting with percutaneous bladder catheterization under ultrasound examination.

e. Prevention
Especially important in Angoras and pets (many castrated males)
Clean water at all times, unfrozen.
Free access to salt
Minimal grain feeding if possible.
Calcium:phosphorus of 2:1   alfalfa hay helps in grain fed animals.
Avoid excessive total minerals or protein in diet.
Ammonium chloride at 2% of grain.
Avoid oxalate containing plants.
Some suggest delaying castration - does make urethra easier to examine, even if effect on urethral diameter may be minimal.
Advise selection of female goats as pets.

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