OlSm Applied Pouluy Science, Inc
STORAGE
TIMEAND OSTRICH
EGG
HATCHABILITY~
H.R. WILSON’, A. R. ELDRED, and C. J. WlLCOX
Department of Daity and Poultry Science, University of Florida, P.O. Bar 110920,
Gainesville, FL 32611-0920
Primary Audience: Ostrich Producers and Hatcheries,Extension Personnel,
Researchers
evidence is available to support these reDESCRIPTION
OF PROBLEM
commendations. In wild ostriches the first
Storage of hatching eggs for a few days
before the beginning of incubation is usually
a desirable management practice so that
batches of eggs are set once or twice a week
and groups of chicks subsequently hatch together. It is recommended that most avian
eggs be stored for 7 days or less prior to incubation [l, 21. However, species variation
exists. For example, storing for 14 days may
severely reduce hatchability of chicken eggs
[l], but may only slightly affect hatchability
of bobwhite quail eggs [3]. Suggested storage
times of ostrich eggs [4] are similar to those
for chicken eggs; however, little experimental
eggs of a clutch may be in the nest for 18
to 21 days before incubation begins, which
reportedly leads to high embryonic mortality
[5ldue to both storage time and sun exposure.
The maximum acceptable time and optimum
environment needs to be determined for
storage of ostrich eggs. To develop efficient
and larger-scale commercial operations,
ostrich breeders need reliable information on
this and many other topics to make sound
management decisions. The objective of the
present study was to determine the effects of
pre-incubation storage time on ostrich egg
hatchability.
1 Florida Agricultural Experiment Station Journal Series Number R-05425
2 To whom correspondence should be addressed
Field Report
217
WILSON et al.
FIELD
REPORT
EXPERIMENT 1
A small pilot study was conducted in
which procedures and equipment were tested
and adjusted, and in which the researchers
gained experience in the incubation and handling of ostrich eggs. Local ostrich farms furnished eggs which were collected the evening
they were laid, dry cleaned upon collection,
stored at 55 to 60°F on the farm for 0 to
14 days, brought to the University of Florida
hatchery, and placed in an incubator upon
arrival. Incubation was in a Natureform incubator [6] with ostrich setting racks. The incubation temperature was 975°F and humidity
varied from 15 to 22% RH. H a t c h was in a
Natureform incubator equipped with ostrich
hatchingbaskets. During hatching the temperature was %.5"Fwith approximately 20%RH.
Eggs were weighed and candled at setting,
weekly thereafter, and at day 38 when the eggs
were transferred to the hatcher. Chicks were
weighed as soon as possible after hatching.
Some chicks were given minimal assistance in
hatching.
A total of 68 eggs were set, 62 of which
were fertile. Hatchabilityranged from 76.7%
for eggs stored 1 4 days to 44.4% for eggs
stored 12-14 days (Table 1). Data collected
from this admittedlysmall sample indicated a
potential detrimental effect due to egg storage
time and a need for further study. Egg weight
loss to day 38 averaged 17.4%, the upper end
of the normal range for ostrich.
EXPERIMENT 2
Eggs were furnished by eight local
breeder farms. Eggs were collected in the
evening after normal oviposition time followed by an early morning check for eggs laid
late. Eggs were dry cleaned when collected
TABLE 1. Effects of storage time on hatchability of
ostrich eggs (Experiment 1)
STORAGE
NUMBER
% Fertile
57.1
9-1 1
12-14
9
44.4
and stored on the farm at 55 to 60°F from 0
to 15 days, depending on the day of oviposition. Eggs were deliveredto the University
of Florida hatchery and held overnight at
68 to 70°F. Settings were made on 14-day
intervals in a Natureform incubator with
ostrich setting racks. Hatching was in the
same type incubator equipped with ostrich
hatching baskets. Incubator temperature was
975°F the first half of the study and 97.3"F
thereafter. Humidity varied from 15 to 22%
RH but was mostly 18 to 20% RH. Hatcher
temperature was %S"F with humidity set at
u)% RH until hatching began, changed to
40% RH during hatching, then returned to
20% RH when the hatch was considered
complete. Eggs were weighed and candled
at setting, weekly thereafter, and on day 38
when the eggs were transferred to the hatcher.
Chicks were weighed as soon as possible after
hatching and again when they were removed
from the hatchery. Some chicks were given
minimal assistance in hatching. A total of
453 eggs were set over 20 settings, with 285, or
63%, being fertile.
Large differences occurred in fertility
(%-loo%) and hatchability of fertile eggs
(19-76%) from different farms. A significant
linear decline (b=-0.39) in hatchability was
found as set number increased (or as breeding season progressed). This type of seasonal
decline commonly occurs in commercial
chicken breeder flocks and will vary with
strain, male:female ratios [7l, and many other
factors. These factors were considered in the
analysis [8]. A consistent, linear decline
(P< .08) in hatchability occurred as storage
time increased (Figure 1). Means are also
shown for data grouped by 3-day intervals
(Table 2). This pattern was similar to that
observed in Experiment 1 and comparable
to that seen in most domestic species studied
[I, 91. If additional studies confirm this pattern, it would indicate that current recommendations for 7 days or less of storage for
maximum hatchabilityof ostrich eggs are valid.
There is also a need for study of storage time
and storage condition interactions.
Actual weight loss of eggs at day 38
was 0.5 to 2.0% less than that projected based
on weight loss at 7 days. This reflects a higher
weight loss during the first week of incubation than in subsequent periods. Similar
observations have been made in broiler
JAPR
218
OSTRICH EGG STORAGE
O I
0
I
I
I
I
I
1
2
3
4
5
I
I
I
I
I
1
I
I
I
I
6 7 8 9 10111213141516
Days Storage
RGURE 1. Decline in hatchability of ostrich eggs with increased storage time. The standard error of the
regression coefficient (-0.01303)is 0.00735 (Experiment 2).
1
chicken eggs [lo] and in ostrich eggs [ll,121. weight, expressed as a percentage of initial
Actual %-day weight loss of eggs that hatched egg weight, averaged 63.6%, with a normal
averaged 13.2%, ranging mostly from 9 to 1 distribution pattern of weights ranging from
16% (Figure 2). This compares to an average 1 56 to 69% (Figure 3). The most common
loss of 13.5% for eggs that survived to 38 dayb weights were 61 to 66%, a range similar to
but did not hatch. Weight losses of more than
those of most domestic species [13]. Some
chicks remained in the hatcher for less than
20% resulted in weak embryos and were det1hr post-hatch, whereas others remained for
rimental to hatching success. Weight losses of
10% or less resulted in edematous embryos up to 4 days. This variation occurred because
of differences in incubation times for eggs
that usually were malpositioned and needed
from a farm and the producer's schedule for
assistance in hatching. Greater embryonic
losses would be expected at the extremes of
chick pickup. Average chick weight when
the weight loss range [12].
removed from the hatcher was 889 g
Average initial egg weight was 1473 g
(C.t!=13.6), reflecting a posthatch loss of
(C.t!=12.9) and average chick weight was
weight. A few chicks were in the range of 50
947 g (C.V. = 12.7). Newly-hatched chick
to 55% of initial egg weight at this stage.
,
NUMBER
HATCH^
MORTALITY
%
Wk of Incubation'
1-3
58
67.2
3.5
4-6
7-9
10-12
13-15
56
64.8
3.8
54
55.4
4.9
60
46
53.3
4.5
52.3
45
STORAGE
DaVS
Field Report
219
WILSON et al.
n
8
W
rn
rn
0
1
7.9
8.0-8.9
9.0-9.9
10.0-10.9
11.0-1
1.9
12.0-1
2.9
13.0-1
3.9
1 4.01 4.9
1 5.01 5.9
1 6.01 6.9
1 7.01 7.9
18.0-1
8.9
19.0-19.9
> =20
5
0
10
15
20
25
30
35
Number of eggs
FIGURE 2. The W a y egg weight loss of ostrich eggs that subsequently hatched (Experiment 2)
56-57
58-59
60-61
62-63
66-67
68-69
0
10
20
30
40
50
Number of chicks
FIGURE 3. Ostrich chick weight at hatch as a percentage of initial egg weight (Experiment 2)
60
70
JAPR
OSTRICH EGG STORAGE
220
Weight loss posthatch averaged 1.35 g/hr with
most values being 0.5 to 2.0 glhr. Edematous
chicks that were allowed to dry down in the
able to walk than those removed immediately
from the hatcher. Placing chicks on "artificial
turf"during this time was helpful in preventing
REFERENCES
ANDNOTES
1. Kosin, LL,1964. Recent research trends in hatchability - related problems of the domestic fowl. World's
Poultry Sci. J. 20254-268.
9. Landauer, W., 1967. The hatchability of chicken
eggs as influenced by environment and heredity. Monograph 1(Revised). S t o m Agr. Exp. Sta., Stom, CT.
2. Wilson, H.R, 1991. Physiological requirements
of the develo ing embryo: Temperature and turning.
10. Vick, S.V., 1. Brake, and TJ. Walsh, 1993. Relationship of incubation humidi and flock a e to hatchability of broiler eggs. Poultry &. 72:251-25e(.
Pages 145-159 in: Avian Incubation. S.G. Tullett, ed.
Butterworth-Heinemann, Boston, MA.
3. Wilson, H.R, 1984. Hatchability of bobwhite quail
: Effect of storage time and temperature. Poultry Sci.
6eK71S-1718.
4. S(ewarI, J.S., 1992. Ratite incubation. Pages336-339
in: 1992 Proc. Assn. Avian Vet., New Orleans, LA.
5. Bertram, B.C.R and kE Burger, 1981.Aspects oi'
incubation in ostriches. Ostrich 523643.
11. Deeming, D.C., L Ayres, and F.J. Ayrrs, 1993.
Observations on the commercial roduction of ostrich
-(
in the United kngdom: Incubation.
Vet. Rec. 132602407.
12. Deeming,D.C., 1995. Factors affecting hatchability
during commercial incubation of ostrich (Struthio
eggs. Br. Poultry Sci. 36:51-65.
m)
g?fep0;Z;
6. Natureform, Inc., Hatchery Systems, Jacksonville,
FL 32202.
13. WUson, H.R, 1991. Interrelationshi
chick size, pthatching growth, and hatcha ility.
Poultry Sa.J. 475-20.
7. WUson. H.R and R H . Harms 1971.Male to female
and egg production-type breeders.
ratios for broilerBr. Poultry Sci. 12%7-331.
14. Harvey, W.R., 1990. User's Guide for LSMLMW
and MIXMDL PC-2 Velsion. Mimeo ph Report,
The Ohio State University, Columbus, Of?
8. Statistical analysis was by ordinary least
analysis of variance usin computer programs o f I % G
. Mathematical mofel included farm, set number,
storage time. In preliminaly analyses, no two-factor
interactions could be detected between main effects and
they were deleted from subsequent analyses.
ACKNOWLEDGEMENT
Financial support from the American Ostrich
Research Foundation, Houston, T X is gratefully acknowledged.