Small Ruminant Nutrition

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Small Ruminant Nutrition

• Nicole Ferguson, DVM, MS

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Seminar Overview

• Anatomy and Physiology
• Nutritional Stages
• Nutritional Diseases
• Hypocalcemia
• Hypomagnesemia
• Copper toxicity
• Enzootic ataxia
• White muscle disease
• Grain overload
• Protein overload
• Bloat
• Recommendations

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Small Ruminant Anatomy
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Small Ruminant Anatomy

• Four stomachs
• Rumen
• Reticulum
• Omasum
• Abomasum
• True stomach
• Most developed stomach in the neonate
• Rumen contractions
• Should occur 2-3 times per minute

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Rumen Anatomy and Physiology

• Rumen
• Numerous protozoa of various sizes
• Neutral pH of 7-7.5
• Green-yellow color
• Aromatic
• Gram-negative rods primarily
• Papilla serve to absorb volatile fatty acids, the
  major source of energy
• Correct function requires roughage with stems of
  a minimum of 1/2-1 long

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Reticulum and Omasum

• The reticulum is closely associated with the
  rumen.
• The reticular groove is a connection from the
  mouth to the omasum, bypassing the rumen.
• This groove is active in neonates with milk
  bypassing the rumen and entering the omasum and
  abomasum when the groove is closed.
• In adults, especially with goats, liquids
  administered in the mouth may stimulate closure
  of the groove.

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Abomasum Anatomy and Physiology

• The abomasum is considered the true stomach in
  ruminants and has similarities to our stomach
  with regards to acid production.
• When the reticular groove is closed, liquids that
  bypass the rumen are absorbed in the abomasum.
• This is the largest stomach in the neonate with
  a transition from a liquid diet to a forage diet,
  the rumen becomes the largest stomach.

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Body Condition Scoring

• Not applicable to neonates
• Some scores range from 1-5
• Ideal BCS of 2.5-3
• Requires feeling the spinous processes and
  transverse processes in the lumbar region

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Nutrient Requirements

• Will vary according to age and stage of gestation
• Energy
• Protein
• Minerals
• Vitamins
• Fiber

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Nutrient Breakdown Energy

• Energy
• First limiting nutrient
• Requirements vary depending on stage and level of
  production, level of activity and intended animal
  use
• Requirement is usually met with medium- to
  high-quality forage
• Dietary deficiency
• Poor growth rate
• Low body condition score
• Decreased fiber production
• Increased disease susceptibility

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Nutrient Breakdown Protein

• Minimum of 7 required for rumen bacterial growth
  and function
• Quantity is more important than quality!
• Grass hay protein content varies from lt6-gt12
• Legume hay protein may be gt28
• Non-protein nitrogen (urea) commonly used to
  increase the protein content of a diet

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Nutrient Breakdown Minerals

• Calcium and phosphorus
• Sodium and chloride
• Magnesium
• Potassium
• Sulfur
• Copper

• Cobalt
• Iron
• Iodine
• Zinc
• Selenium

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Nutrient Breakdown Vitamins

• The rumen normally synthesizes B vitamins in
  healthy animals
• Fat-soluble vitamins are the only requirements in
  healthy animals
• A growth, bone development, vision, skin
• D requirements are met with sunlight exposure
• E antioxidant, associated with selenium, found
  in good quality forage
• K no supplementation is needed in a healthy
  animal required for normal blood clotting and
  sight

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Nutrient Breakdown Fiber

• Required component of the adult ruminant diet
• Dietary fiber content gt 50
• Rumination requires the presence of fiber!
• Limited fiber
• wool pulling
• Decreased milk production
• Pelleted roughage is not a substitute!

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Nutritional Stages

• Lamb and kid
• Yearlings
• Adult male
• Adult female
• Show animals

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Lamb and Kid

• Neonate
• Requires 10-20 of body weight in colostrum
  within 12 hours of birth
• 10-20 of body weight in milk daily (a 20 lb
  lamb or kid should receive ¼-½ gallon of milk
  divided into 4-6 feedings daily)
• Milk replacers 20 protein, 20 fat, whey
  proteins
• Creep feeding
• Must be palatable if going to be successful
• Start by 3-4 weeks of age
• Must consume 0.5 lb daily until weaning if
  increased performed is to be attained
• Should provide an additional 1 lb of weight gain
  for each 4-7 lbs of feed consumed

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Weanlings

• Early weaning at 3-4 weeks of age
• Preferably delay until 8-12 weeks of age
• Stressful!
• Accustom animals to drinking out of a water
  trough and eating out of a bunk prior to weaning
• Offer free-choice good-quality hay for the first
  2 days of weaning
• Introduce to a concentrate feed offered at 1 of
  body weight per day

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Finishing

• Can finish on high-quality forage
• Feedlot or dry lot situations
• Open areas
• Confinement bars
• Combination
• Stepwise feeding program where lambs and kids get
  more grain as they get larger
• High grain diet during this period may predispose
  to urinary stones, enterotoxemia and bloat

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Finishing

• Slowly introduce animals to this diet over 2-4
  weeks and vaccinate against problematic diseases
• High risk of production diseases

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Yearlings

• Small-framed animals can have acceptable
  conception rates at 55-60 of their projected
  mature weight
• Large-framed animals can have acceptable
  conception rates closer to 70 of their mature
  weight.
• Breeding at a mature weight rather than as a
  yearling will maximize the lifetime production of
  that animal.
• Most females gain 0.25-0.5 lb daily from weaning
  until breeding.

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Yearlings

• Keep the body condition score between 2.5 and
  3.5.
• Most males gain 0.75 lb daily during this period.
  
• Monitor males for production-related diseases!

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Adult Male

• Maintain prebreeding BCS of 3-4 as they will lose
  weight during the breeding season
• Feed a concentrated energy-protein supplement 4-6
  weeks before breeding season
• 1-2 lb of concentrate daily is reasonable
• Outside of breeding season, maintain on a
  maintenance feed

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Adult Female

• Maintenance
• Pasture or range settings suffice
• Breeding
• Flushing increased nutrition (energy) before and
  during early breeding increases the ovulation
  rate
• Do not overcondition!
• Provide lush pastures or supplement with 0.33-1
  lb of 10-20 crude protein grain/head/day
• Start 2 weeks before male is introduced and
  continue for 2-3 weeks after
• BCS of 2.5-3 are optimal

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Adult Female

• Early-middle gestation
• Requirements not greatly increased over
  maintenance
• Maintain BCS of 2.5-3 and monitor every 2-3 weeks

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Adult Female

• Late gestation
• 70 of fetal growth occurs during the last 6
  weeks of gestation
• Substantial increase in energy needs
• Feed between 1/3-1 lb grain daily per head
  depending on size of animal
• Maintain BCS of 2.5-3
• Promote adequate energy intake
• Ewes 2.2 lbs daily during final 4 weeks
• Does 1-2 lbs daily during final 4-6 weeks

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Adult Female

• Lactation
• Peak milk production 2-3 weeks after birth
• Rapid decline 8-10 weeks after birth
• Requires adequate levels of proteins prior to
  lactation
• Addition of fat to increase the energy density of
  the diet (do not exceed 4-5 of the diet)

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Hypocalcemia

• Primarily a problem in dairy goats
• Ewes susceptible in late gestation and early
  lactation
• Greatest calcium demand for non-dairy animals is
  3-4 weeks prior to birth
• High producing dairy goats have problems after
  birth
• Signs
• Stiff gait, tremors, tetany, constipation,
  decreased rumen contractions, etc.
• Diagnosis
• History and signalment
• Serum Ca lt 4-5 mg/dl

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Hypocalcemia

• Treatment
• 50-100 ml of a 23 calcium borogluconate solution
  IV
• 50-100 ml of calcium chloride SQ
• Monitor heart rate stop if slows or the rhythm
  changes!
• Prevention
• Diet low in calcium
• Low cation-anion ratio

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Hypomagnesemia

• Grass tetany
• Problem in animals grazing lush pastures during
  early spring
• Reduced absorption of magnesium due to high
  nitrogen and potassium levels in the forage
• Clinical signs
• Ewes 2-4 weeks after lambing
• More common in ewes with twins
• Excitability, convulsions, muscle spasms,
  increased respiratory rate, dead in pasture

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Hypomagnesemia

• Diagnosis
• Serum magnesium lt 1.5 mg/dl or post-mortem
  magnesium levels in CSF, urine or anterior eye
  chamber fluid
• Treatment
• 20-25 calcium borogluconate and 50 ml of 4-5
  magnesium
• Prevention
• Offer high-magnesium mineral supplements before
  growth of lush forage and before lambing

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Copper Toxicosis

• More common in sheep
• Results from chronic accumulation in the liver
  due to getting excess dietary Cu in relation to
  molybdenum or sulfate
• Sources of excess Cu
• Trace mineral mixtures and feeds for cattle and
  horses
• Clinical signs absent during accumulation phase
• Acute disease
• Off feed, lethargy, depression, diarrhea,
  weakness, hemolysis, jaundice, port-wine colored
  urine

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Copper Toxicosis

• Diagnosis
• Blood Cu levels 10-20 x normal (50-200 µg/dl)
• Kidney Cu levels postmortem (gt 100 ppm)
• Liver Cu levels postmortem (gt 350 ppm)
• Treatment
• Usually unsuccessful
• Prevention
• Avoid high dietary Cu, high Cu-Mo ratio,
  Cu-containing foot baths, etc.

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Enzootic Ataxia

• Neurologic disease seen in lambs and kids due to
  copper deficiency in the ewe/doe diet
• Weakness and ataxia (swaying when walking)
  between 2 weeks and 3 months of age
• Diagnosis by doing copper levels in serum
• Many of the changes due to copper deficiency are
  irreversible
• Treatment not attempted

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White Muscle Disease

• Nutritional muscular dystrophy
• Deficiency of selenium and/or
• vitamin E
• Affects skeletal and heart muscle
• Most common in young, rapidly growing animals
• Clinical signs
• Heart form down, respiratory distress, death
• Muscle form most common, stiff gait, tremors,
  firm muscles, painful

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White Muscle Disease

• Diagnosis
• Clinical signs
• Elevated muscle enzymes
• Selenium deficiency
• Vitamin E deficiency
• Treatment
• Vitamin E/selenium injection short acting
• Prevention
• Selenium and vitamin E supplemented in feed
• Selenium/vitamin E injection
• Dams before birth
• Kids/lambs after birth

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Grain Overload

• Rumen acidosis
• Forage-fed animals suddenly introduced to a high
  concentrate diet
• Fermentation of carbohydrates ? decrease in rumen
  pH ? lactic acidosis ? death of rumenal protozoa
  ? fluid from circulatory system drawn into the
  rumen ? dehydration and shock
• Chronic changes
• Liver abscesses
• Laminitis
• Fungal rumenitis

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Grain Overload

• Clinical signs
• Anorexia, depression, weakness
• Severe dehydration, toxemia
• Colic, distended abdomen, diarrhea
• Diagnosis
• Rumen pH lt 5.5
• Few protozoa
• Large gram-positive rods

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Grain Overload

• Treatment
• Correct shock, dehydration, acid-base
  abnormalities
• IV fluids with 5 sodium bicarbonate
• Anti-inflammatories
• Rumen transfaunation
• Thiamine supplementation
• Systemic antibiotics
• Penicillin
• Prevention
• Introduce concentrate feeds slowly over 2-3 weeks
• Rumen buffers
• Minimum crude fiber content of 20

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Protein Overload

• Urea-ammonia toxicity
• Dull, depressed, muscle tremors, frequent
  urination and defecation, excess salivation,
  increased respiration, ataxia, tetanic spasms and
  death
• Treat with vinegar and water via stomach tube
• Do not feed excessive levels of protein or
  non-protein nitrogen

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Bloat

• Frothy bloat
• Diets promoting formation of stable froth
• Ingestion of legume forages or hay, lush cereal
  grain pastures
• Free gas bloat
• Diets promoting excessive gas formation
• Grain diets in animals unadapted to diet
• Failure to eructate
• Esophageal obstruction
• Various other conditions
• EMERGENCY!

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Bloat

• Pass stomach tube of free gas bloat
• Frothy bloat administer DSS or poloxalene, hand
  soap, vegetable oil
• Prevention
• Limit access to above dietary changes
• Add ionophores (monensin) to diet

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In Summary
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Nutritional Recommendations

• Free choice fresh, good quality water
• Each ewe/doe with at least 1 foot of water trough
  space
• Energy
• Structural carbohydrates bulk of diet
• Fat 4-5 maximum
• Protein
• Minimum of 7 dietary crude protein needed for
  normal rumen bacterial growth and function
• Minerals
• Calcium-phosphorus ratio between 11 and 21
• NaCl at 0.5 of diet

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Nutritional Recommendations

• Make feed changes slowly!
• Avoid excessive carbohydrates and protein in diet
• Ensure appropriate stocking density for forages
• See handout on herd health for stocking
  recommendations

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Any Questions?