Encyclopedia Of Animal Science - R docx

Ratites: Biology, Housing, and Management
Dominique Blache
Graeme B. Martin
Irek Malecki
The University of Western Australia, Crawley, Australia
INTRODUCTION
The large flightless ostrich, emu, cassowary, and rhea, and
the small flightless kiwi, compose the ratite family. The
emu, ostrich, and rhea have been used in farming systems
in which their biology influences management and
housing. Ratite farming is in its infancy and requires
further research and development to overcome inherent
constraints before each species can reach its full
productive potential.
BIOLOGY OF RATITES
The flat, raftlike (ratis) sternum provided the name for the
family. There is no keel and the pectoral muscles are
absent or vestigial. In all except rheas, the body feathers
lack barbicels, so the plumage is loose and fluffy. The
feathers of the emu have two shafts. The rhea and the
ostrich have longer wings than the emu and they use them
during elaborate displays (Fig. 1). Female emus and rheas
are larger than males, but the male ostrich is the largest.
[1]
All extant ratites are endemic to the Southern Hemi-
sphere, whereas their ancestors were found in both hemi-
spheres.
[1]
The ostrich, emu, and rhea are found in
temperate and Mediterranean regions, but can survive in a
wide range of climates.

[1,2]
The ratites have very strong legs and their muscles
have a specific distribution and physiology due to the
mechanic constraints of bipedal locomotion. Ratites
walk most of the day and can run at considerable speed
(Table 1). They are nomadic and follow food availability,
but are territorial during the breeding season. Ratites can
also crouch, a posture between standing and sitting
(Fig. 1). The females lay eggs in this position.
[1,2]
Vigilant ratites stand with the neck stretched upward;
their heads are very mobile and can turn almost 360
degrees. Vision is believed to be very efficient because of
the elevated position of the eyes and also because of
acuity. Thus, they are able to see and detect from long
distances (few kilometers). Ratites are not active at night
and spend most of the dark phase lying.
Rheas, emus, and ostriches can be found in groups of
30 or more, but also in smaller family groups. Ratites are
very defensive when eggs or young chicks are present.
Agonistic behaviors include vocalizations, body postures,
and eventual charging.
The reproductive biology of ratites presents some
unique features. The males have a large penile organ that
erects from the cloaca and penetrates the female’s cloaca
during copulation. In females, sperm storage tubules in
the reproductive tract allow the female to remain fertile
for several days after copulation.
[3]
The mating system

varies between species. In the wild, male ostriches and
rheas form harems, but also copulate with females from
other groups, whereas emus form pairs that are stable
during the mating period.
[1,4]
Courtship is based on
vocalizations and displays or postures from both sexes
(Fig. 1). Ostriches reproduce during summer, but rheas
and emus reproduce mainly during winter. Photoperiod is
essential for the emu,
[5]
but is not that critical for the
other ratites because, when nutrition is not limited, they
breed at anytime.
[1]
Ratites nest on the ground in very
simple nests (Fig. 1). Females lay large eggs at 2 3 day
intervals. The total number of eggs laid by one female
varies between species and individuals (Table 1). The
number of eggs laid over a season seems to be strongly
influenced by the level of fat reserves and nutrition of
the female before the start of the laying period. With
the exception of the ostrich, male ratites are solely
responsible for incubating the clutch and raising the
young (Fig. 1). Female emus leave their partner during
incubation and mate with other males. Ratite chicks are
precocious and the nest is usually abandoned within 48 h
after hatching.
[1]
The digestive system is simple and in most respects

similar to that of other plant-eating birds, but ratites also
consume insects and small animals.
[1,2,6]
The esophagus is
mobile and expandable and ratites swallow their food
whole. The crop is absent in all ratites, but the structure of
the stomach varies among species.
[6]
Their appetite varies
dramatically between the breeding and the nonbreeding
seasons, leading to large variations in body weight, mostly
due to variation in fat reserves.
Encyclopedia of Animal Science 763
DOI: 10.1081/E EAS 120019782
Copyright D 2005 by Marcel Dekker, Inc. All rights reserved.
HOUSING AND MANAGEMENT OF RATITES
The allocation of space to farmed birds varies with their
age and reproductive status (Table 2). Only young chicks
need access to an indoor pen. Feeding recommendations
for ratites are not as precise as those for commercial
poultry. Nutrient requirements are based on restricted data
for ostriches and emus,
[2,6]
and there are no published data
for rheas (Table 2). Feedstuffs of plant origin are the main
constituent of the diet and, because of the requirement of
Table 1 Ratite biology
Species Emu Ostrich Rhea
Number of subspecies
a

14 2
Origin Australia Africa Southeastern America
Farming Yes Yes Yes
Sexual dimorphism Not obvious Yes Not obvious
Size (m) 1.5 1.8 1.8 2.5 1.5
Weight (kg) 45 67 80 140 15 40
Number of digits per foot 3 2 3
Running speed (km/h) 45 60 45
Breeding season Autumn winter (SD) Spring summer (LD)
b
Winter (SD)
e
Cluch size
c
(eggs) 5 45 8 36 8 56
Egg production per female 22±5 50 ± 20 16 30
Duration of incubation
d
(days) 56 42 30 44
Incubating sex Male Male and female Male
a
Only present subspecies.
b
Breeding season in ostriches varies regionally in Africa and is influenced by rain and food availability.
c
Number of eggs found in one nest.
d
Incubation under natural conditions.
e
SD short day breeder, LD long day breeder.

(Data from author’s observations and Ref. 1.)
Fig. 1 Clockwise from the top left corner. Male ostrich with his harem; one female is incubating. Male ostrich displaying courtship.
Male emu displaying courtship. (View this art in color at www.dekker.com.)
764 Ratites: Biology, Housing, and Management
these large birds, a large amount of protein has to be
included. Most farmed ratites are fed a pelleted diet of
crushed grain and other nutrients, formulated according to
age and reproductive status.
[2,6,7]
Usually, the diet of
females is richer in energy and protein during the breeding
season than during the nonbreeding season. However, this
strategy might not be best considering that, naturally, the
birds decrease their intake during the breeding season and
replenish their reserves during the nonbreeding season. In
emus, feed intake is controlled by photoperiod and
increases dramatically, by at least 150% (up to 2 kg/
day/bird), when the breeding season ends, allowing them
to recover, within two weeks, most of the weight lost over
the breeding season.
[8]
Breeding management differs between countries and
farms, but the relative advantages of the different strate-
gies have not been compared scientifically. Ostriches
are kept in pairs, trios (one male for two females), or
colonies.
[2]
Emus can breed in pairs or in groups. Rheas are
bred in groups because of their need for harem formation.
Breeding birds are given more space because of the

possibility of fighting. Reproductive failure can be due to
behavioural problems, such as lack of pair formation.
Eggs are usually collected and artificially incubated
to avoid the assembly of a clutch because the males
become sexually inactive as they incubate. Eggs need to
be cleaned and dried before being set into incubators.
Damaged, under- and oversized eggs should be dis-
carded. Storage of eggs before incubation simplifies
hatchery management because it allows batch hatching.
Optimal conditions for artificial incubation are known
(Table 2).
[2,6,7]
Candling of ratite eggs is possible using
commercially available devices. Recommendations for
hatching conditions are not scientifically proven (Table 2),
but the eggs are usually transferred to the hatcher a few
days before hatch date because pipping starts 36 hours
prior to hatching.
Sexual maturity is reached at 18 20 months for os-
triches and emus and after 24 months for rheas (Table 2).
Vent sexing can be successfully carried out within days
after hatching with an accuracy of around 85%.
RATITE PRODUCTION
Farming of ratites has great potential that has been
exploited most often in the countries of origin of the species.
Slaughter age is around 12 16 months for emus, 10 12
months for ostriches, and 18 20 months for rheas. Methods
and regulations for slaughter are already in place in each
country, but more development is needed to decrease the
cost of slaughtering, especially plucking methods.

The products are all high quality: soft leather, meat
with low-fat and high-iron content, and a fine oil that
can be used as a cosmetic base for the administration of
topical medicines and as an anti-inflammatory agent, a
claim already supported by clinical trials for emu oil.
Ostrich feathers have been successfully marketed in
the past as a fashion item but this market has virtually
disappeared. The meat market is still small and in need of
more marketing for further expansion. There is also a need
for more scientific input into management and genetic
selection to improve productivity and product quality.
Recent developments of sperm collection and preserva-
tion, and artificial insemination techniques specific to
both ostrich and emus, provide the industry with major
tools for modern methods of selection.
[9]
CONCLUSION
Ratites are scientifically interesting because of their
unique biological characteristics. Those same character-
istics offer a unique opportunity to develop an alternative
industry that might have less environmental impact than
Table 2 Housing conditions and management of farmed emus
and ostriches
Species Emu Ostrich
Space allocation (m
2
/bird)
a
Chicks (0 12 weeks) indoor pen 0.15 0.20 0.25 0.30
Chicks (0 12 weeks) outdoor pen 0.30 0.50

Chicks (3 6 months) 6 20 10 40
Young (6 12 months) 20 40 50 250
Yearling (12 24 months) 60 100 100 330
Breeders (>24 months)
Free range 625 1000 500 2000
Breeding pairs 400 1200 600 2500
Maintenance requirement
Energy (kJ/kg
0.75
/day) 284 440
Nitrogen
b
(mg/kg
0.75
/day) 320 320
Incubation
Dry bulb temperature (°C) 35.3 36.4
Relative humidity (%) 40 25 30
Air flow (m
3
/min/40 eggs) 0.71 1.42
Air quality (% O
2
,%CO
2
) 21, 0.05 21, 0.05
Rotation of the eggs
Amplitude (degree) 180 90
Frequency (h) 4 8 1
Total egg weight lost (%) 15 15

Hatching
Dry bulb temperature (°C) 35 34
Relative humidity (%) 50 25 35
Space allocations vary according to feeding methods.
a
Based on regulations and practices used by the industry.
b
Based on nitrogen requirement of poultry.
Ratites: Biology, Housing, and Management 765
traditional, imported animal industries. These industries
exist, but still need a large amount of research and devel-
opment before they will be successful because ratites are
not simply bigger versions of common poultry and cannot
be treated as such.
[10]
REFERENCES
1. Davies, S.J.J.F. Ratites and Tinamous: Tinamidae, Rhe
idae, Dromaiidae, Casuariidae, Apterygidae, Struthioni
dae; Oxford University Press: Oxford, 2002.
2. Deeming, D.C. The Ostrich: Biology, Production and
Health; CAB International: Wallingford, UK, 1999.
3. Malecki, I.; Martin, G.B. Fertile period and clutch size in
the Emu (Dromaius novaehollandiae). Emu 2002, 102,
165 170.
4. Blache, D.; Barrett, C.D.; Martin, G.B. Social mating
system and sexual behaviour in the emu, Dromaius
novaehollandiae. Emu 2000, 100, 161 168.
5. Blache, D.; Talbot, R.T.; Blackberry, M.A.; Williams,
K.M.; Martin, G.B.; Sharp, P.J. Photoperiodic control of
the secretion of luteinizing hormone, prolactin and

testosterone in the male emu (Dromaius novaehollandiae),
a bird that breeds on short days. J. Neuroendocrinol. 2001,
13, 998 1006.
6. Tully, T.N.; Shane, S.M. Ratite: Management, Medicine
and Surgery; Krieger: Malabar, 1996.
7. Deeming, D.C. Improving Our Understanding of Ratites in
a Farming Environment; Ratite Conference: Manchester,
UK, 1996.
8. Blache, D.; Martin, G.B. Day length affects feeding
behaviour and food intake in adult male emus (Dromaius
novaehollandiae). Br. Poult. Sci. 1999, 40, 573 578.
9. Malecki, I.A.; Martin, G.B.; Lindsay, D.R. Semen
production by the male emu (Dromaius novohollandiae).
1. Methods for collection of semen. Poult. Sci. 1996, 76,
615 621.
10. Malecki, I.; Blache, D.; Martin, G. Emu biology and
farming Developing management strategies for a valu
able resource. Land Management October 2001, 20 21.
766 Ratites: Biology, Housing, and Management
Ratites: Nutrition Management
James Sales
University of Maryland, College Park, Maryland, U.S.A.
INTRODUCTION
Ratites (order Struthioniformes) are flightless birds with a
raftlike breastbone devoid of a keel, and can be classified
into the families Struthionidae (ostriches), Dromiceiidae
(emus), Rheidae (rheas), Casuariidae (cassowaries), and
Apterygidae (kiwis).
DIGESTIVE PHYSIOLOGY
Despite their similarities to other birds, ratites have

developed unique characteristics, such as modifications in
the gastrointestinal tract, in order to survive in their
natural habitat.
[1]
Ratites do not have teeth or a crop (the
feed storage organ in other avian species). Ostriches,
emus, and rheas could be considered monogastric her-
bivores, which means they are simple-stomached animals
that have developed the ability to utilize forage. Whereas
fiber fermentation appears to take place in the large
intestine (colon) of the ostrich, the distal ileum serves as a
fermentation organ in the emu. The most distinctive char-
acteristic of the gastrointestinal tract of the rhea is the
relatively large cecum (Table 1).
RATITE DIETS
Many different diets have been utilized in commercial
ostrich production, varying from single ingredients such as
alfalfa, to compound diets with several ingredients
including vitamin/mineral mixtures, since the domestica-
tion of the ostrich as a farm animal around 1865 in South
Africa.
[2]
The first book on ostrich feeds and feeding was
already published in 1913 by Dowsley and Gardner.
[3]
Reliance on compound, commercial, manufactured diets,
mostly in a pelleted form, has become the norm since the
spread of ostrich farming to countries outside South Africa
around 1990 and the recognition of emu farming as being
technically feasible in Australia in 1987.

[4]
At the few pilot
operations for the domestication of the rhea as a
commercial farm animal in South America, a variety of
compound pelleted diets, consisting mainly of alfalfa and
corn meal, are fed.
[5]
NUTRIENT REQUIREMENTS
The inaccuracy of earlier extrapolation of nutrient
requirement specifications for poultry to ostriches and
emus soon became evident from various nutrition-related
problems encountered by commercial ratite farmers.
[6]
Studies by Cilliers
[7]
and O’Malley
[4]
revealed significant
information on the energy and amino acid requirements of
these two species (Tables 2 and 3).
It is evident that different diets, each with different
nutrient concentrations, have to be fed at different stages
of the life cycle; for example, a starter diet up to three
months of age, a grower diet till slaughter age, and a
breeder diet for breeder birds.
Mineral Requirements
Currently, dietary mineral, as vitamin, specifications for
ratites are based on suggestions. A major problem in
ostrich feeding is that calcium is very often overfed,
with the result of depressed uptake of zinc and

manganese. Although a total dietary calcium concentra-
tion of 2.0 to 2.5% is recommended for ostrich layers in
intensive production systems, excellent laying and
fertility results have been achieved with dietary calcium
levels as low as 1.6% on a dry matter basis.
[8]
Under
intensive farming conditions, leg problems seldom occur
in young ostrich chicks fed a diet with calcium levels
around 1.5 to 1.6%.
[9]
NUTRITION OF CHICKS
Although the rearing of young ostriches is a well-
established practice, high mortalities are often encoun-
tered.
[9]
Ostrich feed and water should be available from
day one after hatch. A chopped fresh alfalfa or grass
topping on feed will stimulate chicks to start eating. It was
also found in rhea chicks
[10]
that the first few chicks
required frequent stimulation, for example, by poking with
a finger or pencil at the food, to induce proper feeding.
Many ostrich producers supplement the starter diet or
water of the newly hatched ostrich with a booster pack
containing: 1) electrolytes that will ensure that the correct
Encyclopedia of Animal Science 767
DOI: 10.1081/E EAS 120019784
Copyright D 2005 by Marcel Dekker, Inc. All rights reserved.

ratio of sodium to potassium will be consumed and that the
absorption of moisture will be normal during these early
stages of life; 2) acidification substances that will lower
the pH of the digestive tract and enhance its adaptation to
high-protein starter diets; 3) amylase, protease, and
cellulase enzymes to ensure more efficient digestion
of starch, protein, and fiber; and 4) vitamins A, D, E,
and B complex to ensure immunity against infections and
other diseases.
[8]
It is well known that ostrich chicks have
poor resistance against infectious and other diseases. The
supplementation of any product, for example, yogurt, that
might stimulate immunity is highly recommended.
CONCLUSION
Ratites are unique in that they resemble the characteristics
of avian species with nutritional adaptations similar to
that of ruminants. Despite studies on ratites that enable the
modeling of energy and amino acid requirements, dietary
Table 2 Estimated dry matter intake (DMI),
a
energy (TME
n
), and protein and amino acid requirements for maintenance and growth
of African black ostriches
AGE
(Days)
LW
(kg)
ADG

(g/b/d)
DMI
(g/b/d)
TME
n
(MJ/kg
DMI)
Prot
(g/kg
DMI)
Amino acids (g/kg DMI)
Lys Meth Cys Arg Thr Val Isoleu Leu His Phe Tyr
30 4.0 105 220 15.2
b
239 10.6 3.1 2.8 9.8 6.5 7.9 8.7 14.5 3.6 8.5 4.4
60 11.0 233 440 17.5
b
272 12.5 3.6 3.3 11.5 7.6 9.3 10.3 17.0 4.3 10.0 5.1
90 19.5 283 680 15.3
b
224 10.8 3.2 2.8 10.1 6.6 8.2 9.0 14.7 3.8 8.7 4.5
120 28.5 300 820 14.9
b
207 10.6 3.2 2.7 9.9 6.4 8.1 8.8 14.3 3.8 8.5 4.5
150 39.5 367 1220 12.5
b
174 9.1 2.7 2.3 8.5 5.5 7.0 7.6 12.3 3.3 7.3 3.9
180 52.1 420 1490 12.2
b
168 9.0 2.7 2.3 8.5 5.5 6.9 7.6 12.2 3.3 7.2 3.9

210 63.4 375 1630 11.3 148 8.5 2.6 2.1 8.0 5.1 6.6 7.2 11.4 3.1 6.8 3.7
240 73.3 330 1710 10.8 135 8.2 2.5 2.0 7.8 5.0 6.4 7.0 11.0 3.1 6.6 3.6
270 82.4 305 1760 10.7 130 8.3 2.6 2.0 7.9 5.0 6.5 7.1 11.1 3.1 6.6 3.7
300 91.0 287 1800 10.8 128 8.4 2.6 2.0 8.1 5.1 6.7 7.2 11.2 3.2 6.7 3.8
330 96.3 177 2160 8.0 85 6.3 2.0 1.5 6.1 3.8 5.1 5.4 8.4 2.4 5.0 2.9
360 99.9 120 2210 7.4 74 5.9 1.9 1.3 5.7 3.5 4.8 5.1 7.8 2.3 4.7 2.7
390 103.5 120 2250 7.4 74 5.9 1.9 1.4 5.8 3.6 4.8 5.2 7.9 2.3 4.7 2.7
420 107.0 117 2250 7.5 75 6.1 2.0 1.4 5.9 3.7 4.9 5.3 8.1 2.4 4.8 2.8
450 110.0 100 2250 7.5 73 6.1 2.0 1.4 5.9 3.7 5.0 5.3 8.0 2.4 4.8 2.8
480 112.3 77 2250 7.3 69 6.0 1.9 1.3 5.9 3.6 4.9 5.2 7.9 2.4 4.8 2.8
510 114.2 63 2250 7.3 67 6.0 1.9 1.3 5.9 3.6 4.9 5.2 7.9 2.4 4.7 2.8
540 116.0 60 2250 7.3 67 6.0 2.0 1.3 5.9 3.6 5.0 5.3 8.0 2.4 4.8 2.8
570 118.6 87 2250 7.7 74 6.4 2.1 1.4 6.2 3.8 5.2 5.6 8.4 2.5 5.1 3.0
600 120.3 57 2250 7.5 68 6.2 2.0 1.4 6.1 3.7 5.1 5.4 8.2 2.5 4.9 2.9
LW live weight; ADG average daily gain; DMI dry matter intake; TME
n
true metabolizable energy corrected for nitrogen retention; Prot protein;
Lys lysine; Met methionine; Cys cystein; Arg arginine; Thr threonine; Val valine; Isoleu isoleucine; Leu leucine; His histidine; Phe phe
nylalanine; Tyr tyrosine.
a
Based on a diet with a TME
n
(ostrich) content of 11.25 MJ/kg.
b
In calculating TME
n
requirements from results obtained for seven month old birds, similar energy contents were assumed for younger birds. This
assuption is incorrect, resulting in an overestimation of dietary energy requirements.
(From Ref. 7.)
Table 1 Comparison of the digestive tract of ostriches, emus, and rheas

Region
Length (cm) Relative length (% of total)
Ostrich Emu Rhea Ostrich Emu Rhea
Small intestine 512 51 140 36 90 61
Cecum 94 7 48 6 2 21
Colon 800 28 40 57 7 17
(From Ref. 1.)
768 Ratites: Nutrition Management
recommendations on minerals and other nutrients are still
based on data from other avian species. Different dietary
nutrient concentrations are needed through the successive
stages of the life cycle. Low immunity in the digestive
system of the ratite chick until the age of three months is
one of the reasons for high mortalities.
Of the commercial ratite species (ostriches, emus,
rheas), nutritional research has mainly concentrated on the
ostrich. Due to similarities in the digestive system,
information obtained with ostriches could probably be
extrapolated to the rhea, the least studied species.
REFERENCES
1. Angel, C.R. A review of ratite nutrition. Anim. Feed Sci.
Technol. 1996, 60, 241 246.
2. Drenowatz, C.; Sales, J.; Sarasqueta, D.V.; Weilbrenner, A.
History & Geography. In Ratite Encyclopedia; Drenowatz,
C., Ed.; Ratite Records, Inc.: San Antonio, TX, USA, 1995;
3 29.
3. Dowsley, W.G.; Gardner, C. Ostrich Foods and Feed
ing; Crocott & Sherry: Grahamstown, South Africa,
1913.
4. O’Malley, P.J. An Estimate of the Nutritional Require

ments of Emus. In Improving Our Understanding of
Ratites in a Farming Environment; Deeming, D.C., Ed.;
Ratite Conference: Oxfordshire, UK, 1996; 92 108.
5. Sales, J.; Navarro, J.L.; Bellis, L.; Manero, A.; Lizurume,
M.; Martella, M.B. Carcass and component yields of rheas.
Br. Poult. Sci. 1997, 38, 378 380.
6. Cilliers, S.C.; Angel, C.R. Basic Concepts and Recent
Advances in Digestion and Nutrition. In The Ostrich:
Biology, Production and Health; Deeming, D.C., Ed.; CAB
International: Wallingford, Oxon, U.K., 1999; 105 128.
7. Cilliers, S.C. Feedstuffs Evaluation in Ostriches (Struthio
camelus). Ph.D. Thesis; University of Stellenbosch: South
Africa, 1995.
8. Smith, W.A.; Sales, J. Feeding and Feed Management.
In Practical Guide for Ostrich Management and Ostrich
Products; Smith, W.A., Ed.; An Alltech Inc. Publica
tion, University of Stellenbosch Publishers: Stellen
bosch, South Africa, 1995; 8 19.
9. Verwoerd, D.J.; Deeming, D.C.; Angel, C.R.; Perelman,
B. Rearing Environments Around the World. In The
Ostrich: Biology, Production and Health; Deeming,
D.C., Ed.; CAB International: Wallingford, Oxon, U.K.,
1999; 191 216.
10. Kruczek, R. Breeding Darwin’s rheas at Brookfield Zoo
Chicago. Int. Zoo Yearb. 1968, 8, 150 153.
Table 3 Estimated dry matter intake (DMI),
a
and protein and amino acid requirements for maintenance and growth of emus
AGE
(Weeks)

LW
(kg)
ADG
(g/b/d)
DMI
(g/b/d)
Prot
(g/kg DMI)
Amino acids (g/kg DMI)
Lys Met Met+Cys Thr Isoleu Leu
0 2 0.5 14 35 119 6.5 1.8 5.9 5.8 5.0 13.1
2 3 0.8 59 88 170 9.8 2.8 6.7 7.9 6.7 17.4
3 4 1.3 80 140 151 8.7 2.5 5.7 6.9 5.9 15.2
4 6 2.3 106 220 137 7.9 2.2 4.8 6.2 5.4 13.7
6 8 3.9 124 259 146 7.7 2.3 5.0 6.7 5.8 14.7
8 10 5.9 153 368 133 7.1 1.8 4.1 6.1 5.3 13.3
10 12 7.8 121 374 116 6.4 1.8 4.1 5.4 4.7 11.8
12 16 10.7 145 561 94 5.3 1.5 3.4 4.4 3.8 9.7
16 20 14.6 134 603 90 5.0 1.5 3.6 4.2 3.7 9.4
20 24 18.2 125 630 89 5.0 1.6 3.8 4.2 3.7 9.4
24 28 23.8 92 597 91 5.2 1.6 4.1 4.4 3.8 9.8
28 32 23.8 95 545 114 6.7 2.1 5.1 5.5 4.8 12.3
32 36 26.1 71 544 116 7.0 2.1 5.3 5.7 4.9 12.6
36 40 28.0 58 614 110 6.9 2.1 5.1 5.4 4.7 12.0
40 44 30.0 80 604 134 8.7 2.5 6.0 6.6 5.6 14.6
44 48 32.5 110 820 113 7.5 2.2 5.0 5.5 4.7 12.3
48 52 35.7 117 851 112 7.3 2.2 5.0 5.4 4.7 12.1
52 56 38.8 104 829 114 7.6 2.2 5.1 5.6 4.8 12.4
56 60 41.5 87 1,051 88 5.8 1.7 3.9 4.3 3.7 9.6
60 62 43.1 72 1,026 88 5.8 1.6 3.9 4.3 3.8 9.6

62 63 44.0 98 1,175 84 5.6 1.6 3.6 4.1 3.6 9.2
LW live weight; ADG average daily gain; DMI dry matter intake; TME
n
true metabolizable energy corrected for nitrogen retention; Prot protein;
Lys lysine; Met methionine; Cys cystein; Thr threonine; Isoleu isoleucine; Leu leucine.
a
Based on a diet with gross energy content of 11.5 MJ.
(From Ref. 4.)
Ratites: Nutrition Management 769
Religious Foods: Jewish and Muslim Laws
for Animal Slaughter/Welfare
Joe M. Regenstein
Cornell University, Ithaca, New York, U.S.A.
Carrie E. Regenstein
University of Wisconsin, Madison, Wisconsin, U.S.A.
Muhammad M. Chaudry
Islamic Food and Nutrition Council, Chicago, Illinois, U.S.A.
INTRODUCTION
The kosher dietary laws determine which foods are fit or
proper for consumption by Jewish consumers who observe
these laws. The halal dietary laws determine which foods
are lawful or permitted for Muslims. The kosher and halal
dietary laws both deal extensively with animal issues.
More details about these laws and the additional require-
ments not covered in this article can be found in other
sources.
[1–7]
KOSHER DIETARY LAWS
Allowed Animals and the
Prohibition of Blood

Ruminants with split hoofs that chew their cud, the
traditional domestic birds, fish with fins and removable
scales, and a few grasshoppers are generally permitted.
Everything else is prohibited.
Ruminants and fowl must be slaughtered according to
Jewish law by a specially trained religious slaughterer
using a special knife that is very straight, very sharp, and
at least twice the neck diameter in length. These animals
are subsequently inspected for various defects. In the
United States, a stricter inspection requirement requires
smooth lungs (Glatt), i.e., less than two perforations or
adhesions. The meat and poultry must be further prepared
by properly removing certain veins, arteries, prohibited
fats, blood, and the sciatic nerve. Therefore, only the front
quarter cuts of red meat are generally used. To remove
more blood, red meat and poultry are soaked and salted
within a specified time period. All animal ingredients for
kosher production must come from kosher-slaughtered
animals. Thus, fats or oils used for kosher products are
mostly obtained from plant sources.
Prohibition of Mixing Milk and Meat
‘‘Thou shalt not seeth the kid in its mother’s milk’’
appears three times in the Torah (the first five books of the
Holy Scriptures) and is therefore considered a very serious
admonition. Meat has been rabbinically extended to
include poultry. Dairy includes all milk derivatives.
To keep meat and milk separate requires that the
processing and handling of all food products and
production equipment that are kosher fall into one of
three categories: meat, dairy, or pareve (neutral).

Pareve includes all plant products plus eggs, fish,
honey, and lac resin (shellac). Pareve foods can be used
with either meat or dairy, except that fish cannot be mixed
directly with meat. Some kosher supervision agencies do
permit products without meat but made on meat equip-
ment to be listed as ‘‘meat equipment (M.E.).’’
Equipment Koshering
There are three ways to make equipment kosher and/or
to change its status. Which procedure is required de-
pends on the equipment’s prior production history.
Converting pareve equipment to use for meat or dairy
does not require kosherization. The first and simplest
equipment kosherization occurs with equipment made
from materials that have only been handled cold. These
require a good caustic/soap cleaning. However, materials
such as ceramics, rubber, earthenware, and porcelain
cannot be koshered.
Heating above 120°F is usually defined rabbinically as
cooking. To kosher these items, the second form of
equipment kosherization requires that the equipment be
thoroughly cleaned with caustic/soap. The equipment
must be left idle for 24 hours and then flooded with
boiling water in the presence of a kosher supervisor. For
ovens or other equipment that use fire, the third form of
770 Encyclopedia of Animal Science
DOI: 10.1081/E EAS 120021146
Copyright D 2005 by Marcel Dekker, Inc. All rights reserved.
equipment kosherization involves heating the metal until
it glows with the rabbi present.
HALAL DIETARY LAWS

Prohibited and Permitted Animals;
Prohibition of Blood
Meat of pigs is strictly prohibited, and so are carnivorous
animals and birds of prey. Some of the animal and birds
are permitted only under special circumstances, e.g.,
horsemeat may be allowed under certain distressing
conditions. Animals fed unclean or filthy feed, e.g.,
sewage or tankage protein, must be fed clean feed for
three to 40 days before slaughter. Eggs and milk must
come from permitted animals. According to Quran, blood
that pours forth is prohibited from being consumed
whether from permitted or nonpermitted animals and
any derivatives.
For seafood, some groups accept only fish with scales
as halal, while others consider everything that lives in
water, all or some of the time, as halal. Animals that live
both in water and on land (e.g., amphibians) are not
consumed by most Muslims.
The status of insects is unclear, except that locust
is specifically mentioned as halal. The use of honey
was very highly recommended by Prophet Muhammad.
Other insect products are generally acceptable; however,
some consider shellac and carmine makrooh offensive to
their psyche.
Proper Slaughtering of Permitted Animals
There are special requirements for slaughtering the
animal. It must be a halal species slaughter by a sane,
adult Muslim with the name of Allah pronounced at
slaughter. The throat is cut in a manner that induces
rapid and complete bleeding, resulting in quick death.

Generally, at least three of the four passages, i.e.,
carotids, jugulars, trachea, and esophagus, must be cut
to give zabiha or dhabiha meat (meat acceptable for
Muslim consumption).
Although kosher meat is similarly slaughtered, a prayer
is not said over each animal. Thus, most Muslim scholars
do not accept kosher meat as halal. In the absence of halal
meats, individual Muslims may choose to purchase kosher
meat products.
Islam places great emphasis on humane treatment of
animals, especially before and during slaughter. Some
conditions include giving the animal proper rest and
water, avoiding or reducing stress, not sharpening knives
in front of animals, and using a very sharp knife. The
animal may only be dismembered after the blood is
drained completely and the animal is lifeless. Animal-
derived food ingredients must be made from Muslim-
slaughtered halal animals.
Hunting of wild halal animals is permitted for the
purpose of eating, but not for pleasure. Allah’s name
should be pronounced when ejecting the tool rather than
when catching the hunt. On catching, the animal must
immediately be bled by slitting the throat. If the blessing
is made at the time of pulling the trigger or shooting an
arrow and the hunted animal dies before the hunter
reaches it, it would still be halal as long as slaughter is
performed and some blood comes out. Fish and seafood
may be hunted or caught by any reasonable means
available as long as it is done humanely.
The requirements of proper slaughtering and bleeding

are applicable to land animals and birds. Fish and other
water creatures need not be ritually slaughtered. Similarly,
there is no special method of killing locust.
The meat of animals that die of natural causes,
diseases, from being gored by other animals, by being
strangled, by falling from a height, through beating, or
killed by wild beasts, is unlawful to be eaten, unless such
animals are slaughtered before they become lifeless. Fish
that dies of itself, if floating on water or lying on shore, is
halal as long as it shows no signs of decay or deterioration.
An animal must not be slaughtered in dedication to
other than Allah, or immolated to anyone other than Allah
under any circumstances.
GELATIN
Gelatin is probably the most controversial kosher and
halal ingredient. Gelatin can be derived from pork skin,
beef bones, or beef skin along with fish skin and bones.
Currently available gelatins even if called kosher are
not acceptable to the mainstream kosher supervision
organizations or to halal consumers. However, limited
kosher hide gelatin is available. Similarly, at least two
sources of certified halal gelatin are available.
BIOTECHNOLOGY
Rabbis and Islamic scholars currently accept products
made by simple genetic engineering, e.g., chymosin
(rennin) used in cheese making. The production con-
ditions in the fermenters must still be kosher or halal, i.e.,
the ingredients and the fermenter, and any subsequent
processing must use kosher or halal equipment and
ingredients of the appropriate status. A product produced

in a dairy medium would be dairy. Mainstream rabbis may
Religious Foods: Jewish and Muslim Laws for Animal Slaughter/Welfare 771
approve porcine lipase made through biotechnology when
it becomes available, if all the other conditions are kosher.
The Muslim community is still considering the issue of
products with a porcine gene; although a final ruling has
not been announced, the leaning seems to be toward
rejecting such materials. If the gene for a porcine-derived
product were synthesized, i.e., it did not come directly
from the pig, Muslim leaders are prepared to accept it. The
religious leaders of both communities have not yet
determined the status of more complex genetic manipu-
lations and, therefore, such a discussion is premature.
ANIMAL WELFARE
In the United States, the Food Marketing Institute
(representing the major supermarkets) and the National
Council of Chain Restaurants (in conjunction with the
production agriculture trade associations) has undertaken
to develop a set of minimal animal welfare standards. As
part of that process, a kosher/halal standard and audit
requirements have been developed, based on the Amer-
ican Meat Institute’s requirement for upright slaughter.
[8]
In addition, the Northeast Sheep and Goat Program at
Cornell University has developed a low-cost, upright
holding pen for small animals, and has identified a
commercial knife appropriate for halal slaughter. The
Cornell program is currently developing a poster on on-
farm humane/halal slaughter that will be available in a
number of different languages (e.g., English, Arabic,

Persian, Spanish).
CONCLUSION
As consumers continue to refine their food requirements,
more companies may well choose to provide kosher and
halal food products in the marketplace.
REFERENCES
1. Chaudry, M.M. Islamic food laws: Philosophical basis
and practical implications. Food Technol. 1992, 6 (10),
92.
2. Chaudry, M.M.; Regenstein, J.M. Implications of bio
technology and genetic engineering for kosher and halal
foods. Trends Food Sci. Technol. 1994, 5, 165 168.
3. Chaudry, M.M.; Regenstein, J.M. Muslim dietary laws:
Food processing and marketing. Enc. Food Sci. 2000,
1682 1684.
4. Regenstein, J.M. Health aspects of kosher foods. Activ.
Rep. Min. Work Groups Sub work Groups R & D Assoc.
1994, 46 (1), 77 83.
5. Regenstein, J.M.; Regenstein, C.E. An introduction to the
kosher (dietary) laws for food scientists and food processors.
Food Technol. 1979, 33 (1), 89 99.
6. Regenstein, J.M.; Regenstein, C.E. The kosher dietary
laws and their implementation in the food industry. Food
Technol. 1988, 42 (6), 86, 88 94.
7. Regenstein, J.M.; Regenstein, C.E. Kosher foods and food
processing. Enc. Food Sci. 2000, 1449 1453.
8. Regenstein, J.M.; Grandin, T. Animal welfare Kosher and
halal. Inst. Food Technol. Relig. Ethnic Foods Div. Newsl.
2002, 5 (1), 3 16.
772 Religious Foods: Jewish and Muslim Laws for Animal Slaughter/Welfare

Rumen Microbiology
Todd R. Callaway
United States Department of Agriculture, Agricultural Research Service, College Station, Texas, U.S.A.
Scott A. Martin
University of Georgia, Athens, Georgia, U.S.A.
R. C. Anderson
Tom S. Edrington
David J. Nisbet
Kenneth J. Genovese
United States Department of Agriculture, Agricultural Research Service, College Station, Texas, U.S.A.
INTRODUCTION
The ruminant animal is able to digest feeds due to a
mutually beneficial relationship with microorganisms in
the rumen (forestomach). These diverse microorganisms
degrade and ferment feedstuffs and in turn, provide the
animal with usable nutrients. The ruminal fermentation is
important to the success of ruminant animals, but is
inefficient. Therefore, strategies have been sought to
improve the efficiency of the ruminal fermentation.
THE RUMINANT ANIMAL
The ability of the ruminant animal to utilize low-quality
fibrous feedstuffs (e.g., grasses and forages) to produce a
high-quality end-product (i.e., meat, milk, and wool) is
the result of a mutually beneficial relationship between
the mammalian host and the fermentative microbial
population inhabiting the rumen (forestomach).
[1]
Animals
equipped with a rumen include cattle, buffalo, sheep,
antelope, gazelle, duiker, reindeer, deer, giraffe, and

goats; other animals that consume grass (e.g., horses and
donkeys) are not considered true ruminants, but rather
utilize a postgastric fermentation. Mammals do not pro-
duce enzymes that degrade cellulose (a primary fibrous
component of plant materials), but ruminants are able to
degrade cellulose via fermentation because of the pres-
ence of the rumen and its resident microbial population.
Ruminant animals are characterized as having teeth
on the bottom jaw, and a hard dental pad on the top.
This arrangement of teeth results in incomplete masti-
cation (chewing) of ingested feed. Feed is swallowed
and deposited into a large pouch (the rumen) at the end
of the esophagus. The rumen is a large chamber (can
compose up to 30% of the mass of the animal) that is
anaerobic (does not contain oxygen) and populated by a
very large, diverse population of microorganisms
(bacteria, protozoa, fungi, and viruses). These micro-
organisms degrade feeds through the process of fermen-
tation (described subsequently). Feedstuffs in the rumen
are continuously broken down into smaller and smaller
pieces by microbial activity as well as regurgitation and
remastication (a process known variously as ruminantion,
or chewing the cud). As feed is broken down to pieces
less than 1mm in size, it passes out of the rumen and
then to the abomasum (or true stomach) for further
degradation and to the intestine for digestion by mam-
malian enzymes.
FERMENTATION: ANAEROBIC DIGESTION
Fermentation is defined as the process of substrate
degradation in the absence of oxygen. The best known

(to humans) fermentations involve the production of beer,
wine, or vinegar (acetate), which is also an important end-
product of ruminal and intestinal fermentations. Nearly
all feed protein and carbohydrates can be degraded by
bacteria via ruminal fermentation to produce volatile
fatty acids (VFA) and microbial cells (Fig. 1). The VFA
are absorbed by the host animal and provide the animal
with a source of carbon and energy for maintenance and
productive functions. The most important VFA to the
animal are acetate (vinegar), propionate, and butyrate.
Microbial cells (bodies) are washed out of the rumen
along with the small feed particles and are also digested,
providing the ruminant animal with an excellent source of
high-quality protein (especially essential amino acids), as
well as B vitamins as a by-product of fermentation. Thus,
the ruminant provides the microorganisms a hospitable
environment and food in exchange for the microorga-
nisms providing nutrients derived from a low-quality feed
to the animal truly, a mutualistic relationship.
Encyclopedia of Animal Science 773
DOI: 10.1081/E EAS 120019789
Copyright D 2005 by Marcel Dekker, Inc. All rights reserved.
Although the ruminal fermentation is generally bene-
ficial to the animal, in some cases, the end-products of the
ruminal fermentation can be detrimental to the animal, or
even to the environment. Some bacteria ferment specific
amino acids (tryptophan) and produce 3-methylindole,
which can be inhaled by the animal, resulting in
asphyxiation (bovine emphysema). Other problems that
can be traced to production of harmful end-products of the

rumen fermentation include bloat (swelling of the rumen
caused by gas production) and lactic acidosis (accumula-
tion of strong acid in the rumen, which damages the
tissues of the rumen and inhibits the beneficial fermen-
tation). Some of the ammonia produced from ruminal
protein fermentation is not utilized by the animal, but is
excreted in the urine and directly impacts the environment
(environmental nitrogen pollution). Methane is a powerful
greenhouse gas produced by ruminal microorganisms that
is eructated (belched) by all ruminant animals.
MICROBIAL ECOLOGY OF THE RUMEN
The rumen is one of the most densely populated and diverse
microbial ecosystems. It is composed of bacteria and
protozoa (single-celled microorganisms), fungi (multicellu-
lar), and viruses. These flora and fauna break down
feedstuffs by sequential colonization and synergistic effort
(i.e., fungi and bacteria can colonize grass fibers, and break
them down to constituent parts, which are further degraded
by bacteria to produce VFA and more bacteria) (Fig. 1). The
most well-understood members of the ruminal ecosystem
are the bacteria and, to a lesser degree, the protozoa.
Well over 200 species of bacteria have been isolated
from the rumen. However, because the rumen microbial
population is very dense, many bacterial species present at
very low populations probably have not been isolated. The
bacterial population is extremely dense and has been
estimated to be as high as 10
10
cells/ml of ruminal fluid
(that is, 10,000,000,000 bacteria/ml). Considering that the

ruminal volume of a cow is 75,000 ml or greater, it is no
surprise that the rumen has been characterized as the
world’s largest fermentation process.
[2]
Ruminal bacteria can ferment nearly all dietary
components, and are often grouped based on their fer-
mentation substrate and/or the end-products of their
metabolic activity (Table 1).
[3]
Some bacteria are general-
ists and can ferment many substrates fairly well (e.g.,
Butyrivibrio), while other bacteria are highly selective in
what they can utilize (i.e., Anaerovibrio), but can ferment
very rapidly. Some bacteria specialize in degrading
cellulose, others primarily degrade protein in the diet,
and still other species produce methane.
Protozoa are larger, multicellular microorganisms.
They can ingest and ferment feedstuffs as well as bacteria
and smaller protozoa and play a role in nitrogen cycling
within the rumen. The exact role of protozoa in the rumen
is still unclear, although they provide a home for some
bacteria to attach to and can share a mutualistic
relationship with these bacteria. Ruminal fungi are
thought to help initiate the degradation of forage and
to quickly utilize oxygen ingested with feedstuffs; how-
ever, the true significance of ruminal fungi is unclear.
Whatever their role in the microbial ecosystem, each
microbial species has adapted to fill a specific niche in this
complex environment.
USE OF ANTIMICROBIALS TO ENHANCE

FERMENTATION EFFICIENCY
The microbial fermentation allows ruminant animals to
utilize low-quality feedstuffs; however, the process of
fermentation is inherently inefficient. It can often require
more than five pounds of feed to produce one pound of
animal gain (meat) or milk. This low-feed efficiency
makes ruminant production in feedlots and dairy farms
quite expensive. Therefore, methods to improve the effi-
ciency of the ruminal fermentation have been examined.
Antibiotics are antimicrobial compounds that kill or
stop the growth of bacteria. Often, antibiotics are used to
treat bacterial diseases in humans or in animals. In some
cases, antibiotics have been used to try to increase the
efficiency of the fermentation or to reduce pathogenic
bacteria (both human and animal) in the gastrointestinal
tract. For example, Tylosin is currently fed to cattle
to reduce the incidence of Fusobacteria necrophorum
(a bacterium responsible for liver abscesses in cattle);
Fig. 1 Activity of the rumen.
774 Rumen Microbiology
neomycin sulfate has been suggested to be used in feedlot
cattle to reduce the human pathogenic bacterium Esche-
richia coli O157:H7.
[4]
However, the use of antibiotics as animal growth
promotants has come under increased scrutiny due to
problems associated with antibiotic resistance (discussed
elsewhere in this encyclopedia). In response to this issue,
the European Union has recently (2003) enacted a ban on
the use of all antimicrobial feed additives in animal

rations; it remains to be seen if the United States will
follow suit. Therefore, the use of antibiotics, especially
those used in human medicine, to enhance the efficiency of
the rumen fermentation is not widespread or encouraged.
Ionophores are the most widely used compound that
can increase the efficiency of ruminant production.
[5]
Ionophores are antimicrobials (but not antibiotics) that
inhibit Gram-positive bacteria. Because the rumen is
populated by both Gram-positive and -negative bacteria,
the Gram-negative bacteria gain a competitive advantage
in the rumen. Due to this shift caused by ionophore
treatment, ruminal methane, ammonia, and lactic acid
production is reduced, and animal growth efficiency is
increased. This increase in efficiency has led to the
widespread use of ionophores in most feedlot cattle in the
United States.
BACTERIAL PATHOGENS IN THE RUMEN
Because the rumen is ideally suited for microbial growth,
it is no surprise that pathogenic bacteria can also inhabit
the rumen. E. coli O157:H7 and Salmonella (many
serotypes) are foodborne pathogenic bacteria that have
been isolated from the rumen. Both Salmonella and E. coli
O157:H7 can pose a risk to humans via direct animal
contact or through consumption of contaminated meat
products. Additionally, some Salmonella serotypes can
cause severe illness in the host animal. Processing plants
do an excellent job of controlling the spread of these
pathogens after slaughter; however, foodborne illnesses
that are associated with ruminant-derived food products

still occur. Therefore, recent research has focused on
strategies to reduce these pathogens in animals prior to
entry into the food chain.
CONCLUSION
Our knowledge of rumen microbiology has grown
immensely over the past 50 years, yet many people still
regard the ruminal fermentation processes as a black box.
Table 1 Groups of important ruminal bacteria, and the dietary components they are capable of fermenting
Dietary component Group of bacteria Important genera
Forage Cellulose fermenting species Ruminococcus
Fibrobacter
Butyrivibrio
Forage Hemicellulose fermenting species Butyrivibrio
Bacteroides (Prevotella)
Ruminococcus
Forage Pectin fermenting species Butyrivibrio
Bacteroides (Prevotella)
Succinovibrio
Streptococcus
Grain Starch fermenting species Streptococcus
Bacteroides (Prevotella)
Succinomonas
Lactobacillus
Any Protein fermenting species Clostridium
Peptostreptococcus
Bacteroides (Prevotella)
Butyrivibrio
Megasphaera
Any Fermentation acid utilizing species Megasphaera
Selenomonas

Anaerovibrio
Any Lipid utilizing species Butyrivibrio
Any Methane producing species Methanobacterium
Methanobrevibacter
(Adapted from Ref. 3, among other sources.)
Rumen Microbiology 775
Like any other well-developed ecosystem, the rumen is
very complex and changes imposed upon the fermentation
can have unintended repercussions throughout the eco-
system, which may have a profound effect on the animal.
Therefore, technologies to improve the efficiency of the
ruminal fermentation proposed for the future (including
introduction of designer bacteria or super-bugs that can
address any perceived shortcomings of the ecosystem)
need to be approached with caution. Future directions of
research into the area of rumen microbiology will
certainly include the use of genomics (sequencing of the
DNA of ruminal microorganisms). The recent complete
sequencing of the genome of predominant cellulose
degrading bacteria will surely allow a greater understand-
ing of the complex ruminal ecosystem.
ARTICLES OF FURTHER INTEREST
Digesta Processing and Fermentation, p. 282
Digestion and Absorption of Nutrients, p. 285
GI Tract: Anatomical and Functional Comparisons,
p. 445
GI Tract: Animal/Microbial Symbiosis,p.449
REFERENCES
1. Hungate, R.E. The Rumen and Its Microbes; Academic
Press: New York, NY, 1966.

2. Weimer, P.J. Cellulose degradation by ruminal micro
organisms. Crit. Rev. Biotechnol. 1992, 12, 189 223.
3. Yokoyama, M.G.; Johnson, K.A. Microbiology of the
Rumen and Intestine. In Microbiology of the Rumen and
Intestine; Waveland Press: Englewood Cliffs, NJ, 1988;
125 144.
4. Elder, R.O.; Keen, J.E.; Wittum, T.E.; Callaway, T.R.;
Edrington, T.S.; Anderson, R.C.; Nisbet, D.J. Intervention to
reduce fecal shedding of enterohemorrhagic Escherichia
coli O157:H7 in naturally infected cattle using neomycin
sulfate. J. Anim. Sci. 2002, 80 (Suppl. 1), 15.
5. Russell, J.B.; Strobel, H.J. Effect of ionophores on ruminal
fermentation. Appl. Envir. Microbiol. 1989, 55, 1 6.
776 Rumen Microbiology