RIZZI ET AL: OSTRICH EGG PRODUCTION
333
triches (Struthio camelus) on a farm situated in
northern Italy at 187 m above sea level from
March to June 1999. Each trio was maintained
in an outdoor enclosure (0.5 hectare) that had a
covered area. Enclosures were covered with
sand. Each breeder consumed 1 to 1.7 kg/d of
a pelleted diet fed ad libitum and composed as
follows (% as fed): 13% moisture, 18% crude
protein, 2.6% ether extract, 9.5% crude fiber,
12.5% ash, and 0.45% methionine. Moreover,
the birds were allowed access to fresh chopped
(2 to 3 cm) alfalfa.
Eggs were collected and weighed just after
laying, which normally occurred in late after-
noon. The laying date and enclosure number
were marked on each egg. After being washed
and disinfected with a Virkon S solution, eggs
were stored at room temperature (15 to 18°C)
with RH between 70 to 75% for a period not
exceeding 12 d. Eggs were set in a 250-egg
capacity Victoria I36 electronic incubator at
36°C and 25 to 35% RH and were turned hourly
throughout the incubation period.
not weighed. Overall fertility of the 99 eggs
produced was 69.7% (Table 1). This result was
consistent with those found on Australian farms
[4] but was lower than the 78.2 and 73.4%
reported for ostrich eggs imported from Zim-
babwe [5] and ostrich farms in Italy [6], respec-
tively. A difference was found among the five
trios, the fertilities being 93.7, 55.5, 90.9, 0,
and 73.7%, respectively.
Hatchabilities of eggs set and fertile eggs
were 51.5 and 73.9%, respectively (Table 1).
Hatchability of eggs set was lower than the
70% expected and reported for artificial incuba-
tion of ostrich eggs by Dzoma and Dorrestein
[7]. However, in Italy, a similar hatchability
(55%) had already been reported [6]; in other
trials, hatchability varied from 37.2% [5] to
68.5% [8]. Hatchability varied greatly among
the four trios, with hatchabilities of fertile eggs
being 73.3, 90, 86.7, and 35.7% and hatchabilit-
ies of egg set being 68.7, 50, 78.8, and
26.3%, respectively.
In ostriches under farming conditions, fer-
tility is affected by factors such as genotype,
nutrition, climate, laying period, age, behavior,
and mate compatibility [7, 9]. The difference
in fertility among the trios were probably due
to the birds, because environmental conditions
and nutrition did not vary among trios. How-
ever, it was not possible to assess the reproduc-
tive efficiency of each bird, because birds were
maintained in trios. The performances of Trios
3 and 4, the best and the worst, respectively,
could have been associated with reproductive
disorders in males or females as well as to
mating behavior. The Trio 5 showed the lowest
hatchability (26.3% for eggs set and 35.7% for
fertile eggs), although fertility was 73.7%.
Factors that affect hatchability include incu-
bation parameters (temperature, humidity, and
egg turning), length of egg storage, egg size,
and shell thickness and porosity [6, 7, 10]. Egg
size and porosity may be affected by season,
hen immaturity, nutrition, and genetics [4]. Be-
cause incubation conditions were the same for
all eggs, egg size as well as shell quality might
have caused reduced hatchability in Trio 5, as
their eggs were lighter during incubation in
comparison with those from the other trios.
Embryonic mortality from set to hatch was
26.1% and greater losses (14.5%) occurred dur-
Eggs were candled at 13, 26, and 38 d using
a 150-W candling lamp. At 38 d, eggs were
transferred into a Victoria H24 hatcher set at
36°C and 42 to 45% RH. All eggs were weighed
at collection, setting, and at each candling. At
hatch, chicks were identified by a subcutaneous
microchip and weighed. Egg weight loss from
set to the third candling was determined as fol-
lows: egg weight loss (%) = [(egg weightat set
−
egg weightDay 38)/egg weightat set] × 100. Chick
weight as a percentage of egg weight at set was
also determined.
Egg weight at set and at each candling, chick
weight at hatch, egg weight loss, and chick
weight percentage were analyzed using the gen-
eral linear models procedure of SAS software
[3]. The statistical model included the following
factors as sources of variation: trio, laying
month, and, as covariates, egg weight at collec-
tion and storage time. Significant differences
among means of each factor were determined
by nonorthogonal contrasts.
RESULTS AND DISCUSSION
In total, 99 eggs were collected and set, but
at collection and set the weight was recorded
for 89 eggs only. Fifty-one chicks hatched, but
one chick died within a few hours and was