BIOLOGY of SWINE
1
REFERENCE
• 畜牧要覽 養豬篇 (增修版) 2001
• 太湖豬育種委員會 1990 中國太湖豬
• 朱瑞民 李坤雄 1990 豬的世界
• Boden, E. 1991 Swine Practice
• Gordon, I. 1997 Controlled Reproduction in Pigs
• Hafez, E. S. E. 2001 Reproduction in Farm Animal
• McDonald L.E. 1989 Veterinary Endocrinology and Reproduction
• Meredith, M. J. 1995 Animal Breeding and Infertility
• Pond, W. G. and Maner, J. H. 1984 Swine Production and Nutrition
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The biology of swine growth and development
Swine production is usually compartmentalized
into two phases: Breeding (reproduction) and
Growing.
A major reason for the compartmentalization is the
need to segregate young animals from older for
Disease Control.
Swine biology may be thought of a Cyclical
Process
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Chromosomes and Body Size
1. The domestic pig has 38 chromosomes (missing 2nd pair)
2. The European wild pigs has 36 chromosomes (missing 6th
and 9th pairs)
3. The hybrid pig has 37 chromosomes (single chromosomes
occupy each of the three positions in which either the domestic or
the wild animal lacks a pair)
4. The sex is determined as male by X and Y chromosomes
5. Detectable chromosome defects are observed at high
proportion of blastocysts (up to 10%)
6. The average mature weight of conventional pigs raised
for meat: 200-300 kg
7. The mature weight of the breeds of miniature pigs
developed for research: < 100 kg
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Karyotype of pig
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Behavior Traits
• Characteristics
– Notoriously curious (suckling)
– Tidy and neat housekeepers
– Smart animals
– Active food-hunters/nibblers
– Omnivore
– Low cooperation ability but with following behavior
• Rooting
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Behavior Traits (cont.)
•
•
Social dominance behavior
–
Group order in large population
–
Complicated order
–
Teat order: established teat position within the first week
Maternal behavior
–
More docile during gestation
–
Nest-building: colostrums can be milked
–
Labor: restlessness, repeated rising and lying down, milk
down
–
Farrowing begins: remaining lying down until the last pig
is born
occasionally: indifferent, hostile, bite or throw their
offspring
–
Nursing and protecting behavior
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Behavior Traits (cont.)
• Suckling behavior
– Urge to suckle
– Teat order
– Suckling pigs: sniff and nibble
• Eating behavior
– Making noise while eating
– Sniff and rooting
– Ad libitum: many small meals throughout 24 hr
(more in daytime)
– Eating and drinking alter (eat more and drink more;
drink more while it is hot)
• Activity and rest behavior
• Breeding behavior
– Standing heat
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Behavior Traits (cont.)
• Tail biting (a peculiar type of cannibalism)
Caused by:
Genetics
Environmental factors
Parasite infection
Nutrition
Curiosity
Result in:
Infection and death
Influencing growth
• Abnormal behavior
Caused by:
Nutrition deficiency
Environmental factors
Diseases
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Life Cycle of Pig
Period
Prenatal period
Suckling period
Growing –finishing period
Mature (reproductive) period
Duration
114 4 days
3 –8 weeks
90 –150 days
Age at 90 kg
120 –200 days
Age at puberty
Optimum age at first service
Reproductive longevity
Longevity
150 –200 days
7 –8 months
4 –8 years
12 –15 years
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Breeding herd biology
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Basic data to estimate growth performance
*Feed (Nutrient) Consumed
*Body Tissue Gained
*Time elapsed to market size
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Growth performance is determined by
•
Gender
•
Age
•
Genetics
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Males (red) gain protein faster than females (yellow) when fed
comparable diets over the same amount of time.
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Females (yellow) accumulate more fat over-all than males (red). But,
after about 7.6 MEI, males' fat gain begins to increase dramatically
compared to females' steady fat gain rate.
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Males gain more weight than females at a given feed amount.
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The X-axis is metabolizable energy
intake (a measure of feed quality),
the Y-axis is feed per gain. If a pig
eats less feed in order to gain a
unit of weight, it is more efficient.
The lower (red) line is considered
more efficient.
Males (red) use feed more efficiently than females (yellow).
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Growth Performance
Boars
Gilts
Barrows
Feed Intake
+
++
+++
Growth Rate
+++
+
++
Carcass Leanness
+++
++
+
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Fast growers (red) gain protein faster than slow growers (yellow). In
addition, the fast growers' protein gain does not plateau; they keep
gaining protein.
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Slow growers (yellow) gain fat faster than fast growers (red).
Remember, "slow grower" could refer to a breed which grows slowly, or
to females, for example, compared to males within a breed.
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Fast growers can reach a higher weight potential than slow growers.
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Fast growers continue to use feed more efficiently than slow
growers at any feed level or quality.
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Gross Anatomy and Carcass Measurement
1. Different numbers of vertebrae
ribs
thoracic vertebrae
lumbar vertebrae
2. Increase the no. of rib
Decrease the no. of lumbar vertebrae
3. Additional ribs
4. Carcass merit
back fat
ham weight
loin eye
breeds of larger size
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Plasticity of the Pig
Changes in the general shape and type of pig
1. High degree of heritability of body type
2. Short generation interval of pig
3. High prolificacy
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Hair and Skin Color
Skin pigmentation generally is associated with hair color
Categories of coat color:
1.
Tortoise-shell patterns: due to a series of triple alleles
a.
Complete extension of black self black
b.
c.
Partial extension of black black spotted ex. Berkshire
Complete restriction of black self red ex. Duroc
ex. Unbelted
Hampshire
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Hampshire
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Berkshire
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Berkshire
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Duroc
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Hair and Skin Color (cont.)
2.
White patterns:
a.
b.
c.
d.
Self white
Slaty or dirty white on dark skin
White belt
White responsible for the white feet, nose and tail
 Self white dominant over most black and red breeds
 The width of the white shoulder belt of Wessex
Saddleback and presumably of the Hampshire
is associated with three genotypes
•
•
•
homozygous belted: medium to wide belt
heterozygous belted: narrow to medium belt
homozygous black: no belt
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Hair and Skin Color (cont.)
3. Color patterns:
The complex nature of coat color inheritance in pigs
white, black, red, gray, brown and all combinations
among crossbred pigs
4. Longitudinal stripes
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Hair and Skin Color (cont.)
Categories of hair types:
1. Curly (woolly) hair: Conastras (Brazilian) pigs
a. Not associated with a particular color or sex gene
but under the influence of a single complete
dominant gene
b. The hair shaft is oval or flat
2.
Sparse hair: Extremadura breed of Spain and Tatu breed of
Brazil
Controlled by an incompletely dominant gene for hair
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Digestion in Swine
 Simple stomached
 Omnivorous –eats both animal and plant
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Mouth
Esophagus
Stomach
Pyloric sphincter
Liver
Gall bladder
Duodenum
Small
intestine
Jejunum
Pancreas
Ileum
Cecum
Large intestine
Colon
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Digestion in Swine (cont.)
I. Mouth
1. Used primarily for grinding feed
2. Saliva
a. pH of 7.4 moistens feed and helps in chewing and
swallowing
b. Produced by 3 pairs of glands parotid, mandibular, and
submaxillary
c. Ptyalin (salivary amylase)
 Pig is the only farm mammal with any amount of the
enzyme
 Starts breaks down starch. Of little value because feed
does not stay in mouth very long and pH of stomach too
acidic for action in stomach
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Digestion in Swine (cont.)
II. Stomach
1. Simple Stomach –monogastric
2. Capacity about 2 gallons (7.6 L)
3. Gastric juice same as for monogastric
a. Mucin
b. HCl
c. Pepsin
d. Gastric lipase
e. Rennin –not found in pig
4. Digestion of protein starts in stomach, completed in SI
5. Fat digestion in small intestine
6. Requires about 24 hrs to empty stomach
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Digestion in Swine (cont.)
III. Small intestine
1. About 60 ft (18.3 m) in length and 2.5 gallons (9.5 L).
2. Fxn = Continue process of digestion with:
a. Pancreatic juice
b. Bile
c. Intestinal juice
d. Movement of intestinal wall
3. Absorption in jejunum and smaller extent in ileum
4. Pancreatic juice
a. Enzymes for proteins, fats, and CHO
b. Buffers –sodium carbonate and bicarbonate
5. Pancreas also produces insulin –CHO metabolism
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Digestion in Swine (cont.)
IV.Protein digestion
1. Trypsin (pancreas)
a. Initially secreted as tryspinogen activated by Ca
ions and enzyme enterokinase
b. Breaksdown protein into amino acids and peptides
2. Chymotrypsin (pancreas)
a. Secreted as chymotrypsinogen, activated by tryspin
b. Breakdown proteins to peptides and amino acids
3. Carboxypeptidase (pancreas)
a. Secreted as procarboxypeptidase, activated by trypsin
b. Acts on peptides, breakdown to amino acids
4. Aminopeptidases (brush border)
a. Act on small peptides, breakdown to amino acids
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Large
Protein
HCl
Parietal cells
Unfolded
Protein
Chief cells
Pepsinogen
Pepsin
Smaller
Protein
Trypsinogen
Pancreas
Enterokinase (BB)
Chymotrysinogen
Trypsin
Smaller
Protein
Chymotrypsin
Smaller
Protein
Procarboxypeptidase
Brush border
Carboxypeptidase
Amino & di/tripeptidases
(enterocytes)
Absorption
Smaller
Protein
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AA, di & tripeptides
Digestion in Swine (cont.)
V. Fats (Lipid)
1. Bile (produced in liver, stored in gall
bladder)
a. Emulsifies fat
b. Digestion and absorption of fat
c. Aids in absorption of water soluble vitamins
d. Activates lipase
2. Pancreatic Lipase (Pancreas)
a. Converts fats into fatty acids and glycerol
b. Action most effective after fats have been
emulsified by the bile
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Digestion in Swine (cont.)
VI.Carbohydrates
1. Pancreatic Amylase
Converts starch to maltose
2. Brush Border enzymes
a. Maltase
Converts maltose to glucose
b. Sucrase
Converts sucrose to glucose and fructose
c. Lactase
Converts lactose to glucose and galactose
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Digestion in Swine (cont.)
VII.Large Intestine
1. 16 ft in length, capacity 2.5 gallons
2. Consists of colon and cecum terminates as rectum
at anus
a. Cecum : ~10 in long, capacity 0.5 gallons
b. Colon : ~16 ft in length, capacity 2 gallons
3. Function = Absorb water and act as reservoir for
waste materials
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Glossary
1. Anus - the last part of the digestive tract through which
undigested food passes out of the body
2. Bile - a secretion of the liver which aids in the digestion of fats
3. Bile Duct - a duct which carries bile from the gall bladder to
the small intestine
4. Cardiac Valve - a valve which prevents food from passing
from the stomach back up into the esophagus
5. Carbohydrates - the main nutrients which supply energy to the
body (starch and cellulose)
6. Cecum - a "blind gut" located between the ileum and the large
intestine
7. Duodenum - the first section of the small intestine
8. Enzymes - substances that speed up chemical reactions within
the body
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Glossary
9. Esophagus - a tube which carries food from the mouth to the
stomach
lO. Fats - energy nutrients which supply 2.25 times as much
energy as carbohydrates
11. Gall Bladder - a sac-like structure which serves as a storage
compartment for bile
12. Ileocecal Valve - the valve separating the ileum and the
cecum
13. Ileum - the terminal portion of the small intestine
14. Jejunum - the intermediate or middle portion of the small
intestine
15. Liver - a gland in the body which performs a number of
functions including the secretion of bile
16. Monogastric - having only one stomach (non-ruminant)
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Glossary
17. Pancreas - a gland which secretes digestive juices necessary
for the digestion of fats, carbohydrates, and proteins
18. Pancreatic Duct - a duct which carries secretions of the
pancreas to the small intestine
19. Polygastric - having more than one stomach (ruminants)
2O. Pyloric Valve - the valve separating the stomach and the
small intestine
21. Proteins - the nutrients which supply the building materials
from which body tissue and many body regulators
are made
22. Rectum - the terminal portion of the large intestine
23. Saliva - an enzyme secreted from the mouth which begins
carbohydrate digestion
24. Villi - tiny finger-like projections located along the wall of the
small intestine which aid in food absorption
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Blood and circulation
* blood volume of the pig: percentage of B.W. decreases
with age
80-90 mL/kg B.W. newborn pig
95-100 mL/kg B.W. after nursing
70-75 mL/kg B.W. 2-3 wks old
30-35 mL/kg B.W. mature obese swine
* blood pressure increases with B.W.
systolic: 50-60 mm Hg at birth
140-160 mm Hg at maturity
diastolic: 30-45 mm Hg lower than
systolic pressure
* heart rate declines with B.W. and age:
200 beats per min at birth
80 beats per min or less at maturity
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Blood and circulation
* cardiac output declines with age:
150 mL/kg B.W. per min in pigs from 7-50 kg
30-40 mL/kg B.W. per min at maturity
Iron deficiency anemia increases cardiac output
* inability of the pig to withstand severe exertion
* limited ability to dissipate heat
(spare sweat glands and large subcutaneous fat insulation)
* relatively small heart (wide variation)
* relatively small blood volume
* unstable circulatory physiology
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Hematology
* Hematopoiesis begins during fetal life
Hemoglobin
and hematocrit
are indices of
iron nutrition
* RBC (erythrocytes)
Suckling period
 source of supplemental iron for hemoglobin synthesis
 milk iron is deficient
microcytic hypochromic anemia
Life of RBC is 70 days
* WBC (leukocytes)
Fewer in number, wider normal range and lower
average concentration in the newborn animal than
RBC
50% lymphocytes; 38% neutrophils, 5% esosinophils,
2% basophils;
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Serum proteins
* poorly supplied in the newborn pigs until the first
colostrum is ingested
plasma proteins 2.4 g/100 mL blood before nursing
serum proteins 7 g/100 mL blood by 8-10 wks old and
remain until and during mature life
* serum proteins initially provided by colostrum, soon
produced by liver (large amount), spleen and bone
marrow
* ration of albumin to globulin is an index of protein
nutrition
prolonged protein deficiency
maintain serum gamma globulin at the same absolute
level albumin is reduced to almost zero
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Dentition
Needle teeth
* At birth: 8 teeth,
teeth including 4 incisors and 4 canines
* The full complement of temporary teeth (deciduous
teeth): 28,
28 including 12 incisors (3 pairs on upper and lower
jaws), 4 canines (one pair on upper and lower jaws), 12
molars (3 pairs on upper and lower jaws)
* The permanent teeth: 44,
44 including 3 pairs of incisors, 1 pair
of canines, 4 pairs of premolars and 3 pairs of molars, upper
and lower jaws
from 3 or 4 months to 18 or 20 months
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