feeding sheep and goats

Sheep and Goat Industries

• Sheep population in US – 5.05 million

  • Very important species historically

  • Wool vs. meat driving the industry

  • Numbers declining in US

• Goat population in US – 2.47 million

  • Important species worldwide (1 billion)

  • Numbers increasing US (over past decade)

Major Considerations

• Biological type – more diversity with sheep than with other food animals, and its market driven, not fads

• Many different management systems, from intensive to very extensive, resulting in just as much diversity in feeding programs that are applied

What is Wool?

• Fiber is made of 19 different amino acids combine into a keratin-like protein linked in polypeptide chains

Essential Amino Acids

• Phenylalanine

• Valine

• Threonine*

• Tryptophan*

• Isoleucine

• Methionine*

• Histidine

• Arginine

• Leucine

• Lysine 

• Another important one is cysteine

• Methionine and cysteine include sulfur in their chemistry

Grazing Programs for Sheep

• Behavioral and physiological considerations

  • Highly selective grazers, prefer legumes and broadleafs to grasses

  • Mouth construction

  • Flock together

• Susceptible to parasites

• Easy to fence sheep in a pasture

• Harder to keep predators out of pasture

Diet Selection of Livestock

• A mixture of grass and legumes

• Woody material

Sheep and Pasture

• Weaned lambs should get the best pasture; mama ewes from these lambs can tolerate lower quality forage

• In drought or overstocked conditions, wean lambs early and put them in a drylot

  • Accelerated Lambing Programs

• Utilize stockpiled forage

Consider Companion Grazing with Sheep

• With cattle

• Advantages:

  • Reduces parasitic infestation

  • Each will eat around the others’ droppings

  • Assures more uniform use of the pasture

Biological Functions that Drive the Feeding Program

• For all food animal production systems, not just sheep, there are two productive functions that are most important and determine nutrient requirements:

  • Estrus

  • Ovulation rate

Components of Reproduction

• In estrus or not –

  • Postpartum anestrous

  • Seasonality of estrous activity

• Ovulation rate – determines potential number of lambs born

  • Flushing

Practical Aspects of Energy Status in Ewes

• ENERGY – most important component in sheep diets

  • BW changes with physiological state

• BCS – evaluated by palpating rib/spine

Change in Energy Requirement (Also Body Weight) at Different Stages of Production of a Ewe

• Dry period = non lactating

Sources of the Heat Increment of Pregnancy in Sheep

Ewe Feeding Programs for Maintenance/Early Gestation

• Average quality pasture or hay

• No grain supplementation

• Always mineral supplementation

• Goal: to maintain, if not gain, body condition for upcoming pregnancy or lactation

Ewe Feeding Programs for Late Gestation, Lactation

• Excellent quality pasture/hay plus some grain

  • Beware of pregnancy disease

• Grain silage, plus protein and mineral

  • Supplementation

• Goal: to support fetal growth/milk production and control body weight loss due to fat mobilization
  

• Early lactation is the time of highest nutrient requirements in the entire production cycle; nursing twins takes lots of feed

  • 40% to 50% more milk is produced when nursing twins

  • Ewes cannot eat enough feed to support this level of production, so they lose weight

• A general recommendation is to provide high quality forage, plus 1 pound of grain for each lamb a ewe is nursing

Daily Ewe Feed Requirements – 155 lb ewe; DM Basis (NRC Table)

Grain vs Pasture for Finishing

• Grain feeding:

  • Faster gain

  • Less parasites

  • Higher QG and DP

  • Higher cost of gain

  • Preferred by American consumers

• Pasture finishing:

  • Less labor

  • Lower cost

  • “Natural” production

  • Product composition

  • Limited by season

  • Requires the best quality forage

  

Nutrient Requirements – Percent Protein Varies the Most

• Younger lamb = higher protein content in diet

Protein Deficiency in Sheep

• Reduced appetite and feed intake

• Reduced birth weights and growth

• Reduced colostrum and milk production

• Decreased hormonal production

• Decreased fertility

• Reduced wool growth

Non-Protein Nitrogen (NPN)

• Nitrogen supplied to the animal in a non-protein state

  • Urea or biuret

• Requires microbial synthesis (ruminants)

• Crude protein equivalent

  • % nitrogen from NPN times a factor of 6.25

Protein (Nitrogen) Utilization by the Ruminant

• Ammonia = key central product

• Corn = fattening feed

  • Higher TDN content

• Oats = growing feed

  • More fiber

  • Higher protein content

Why No NPN Additions to Creep Feeds?

• How old are the lambs/kids?

• Do they have a functioning rumen yet?

• Do they have a typical microbial population in their rumen yet?

• Can they utilize NPN to make AA?

Lambs Fed High Grain Diets

• Beware of:

  • Urinary calculi

    • Imbalance of Ca:P ratio

    • Add limestone to diet

  • Polioencephalomalacia

    • Created thiamine deficiency

    • IV and IM injections of thiamine hydrochloride and lots of TLC

  • Enterotoxemia (overeating disease)

    • Vaccinate

  • Pregnancy disease (ketosis)

    • Energy deficiency

  •  White muscle disease

    • Se/Vitamin E deficiency

  • Toxic or poisonous plants

Special Considerations with Sheep

• Selenium deficiency

  • Mineral supplements should contain up to 90 ppm Se, which is maximum allowed by FDA

• Copper toxicity (<17 ppm Cu)

  • Cu accumulates in liver – kills the cells

Goats

• Cu requirements

• Differences in grazing

• Fencing

• Susceptible to similar diseases and conditions as sheep