Incubation Temperature for Ostrich (Struthio camelus) Eggs

Abstract

The impact of incubation temperature on egg weight loss, embryonic mortality, incubation period, hatchability, and chick weight in 394 ostrich (Struthio camelus) eggs was studied. Eggs were obtained from 3 farms in Texas. Three incubation temperatures (36.5, 37.0, or 37.5 degrees C) with relative humidity ranging from 20 to 30% were used. Results showed that incubation of fertile eggs at 36.5 degrees C increased hatchability and incubation period in comparison with other treatments. The incidence of dead in shell and total dead embryos was increased at 37.5 degrees C when compared with 36.5 degrees C. No differences in hatchability, incubation period, dead-in-shell embryos, and total dead embryos were observed between eggs incubated at 37.0 or 37.5 degrees C. Neither chick weight nor egg weight loss at 7, 14, 28, or 38 d of incubation was affected by incubation temperature, but egg weight loss at 21 d was lower for eggs incubated at 37.5 degrees C than for the other treatments. Results show that the most effective incubation temperature for the ostrich is lower than the most effective incubation temperature for most bird species.

Effects of thermal manipulation during late incubation period on post-hatch thermotolerance in ostrich

“…Increasing the incubation temperature from 36.0 to 37.2°C reduces hatchability from 73 to 44% (Stewart 1996). Similar results were found by Hassan et al (2004), who reported that mortality was increased at 37.5°C if compared to 36.5°C. The incubation period was reduced by about 2 days when the incubation temperature increased from 36.5 to 37.5°C (Hassan et al 2004).…”

“…Similar results were found by Hassan et al (2004), who reported that mortality was increased at 37.5°C if compared to 36.5°C. The incubation period was reduced by about 2 days when the incubation temperature increased from 36.5 to 37.5°C (Hassan et al 2004). However, Stewart (1996) noticed that increasing the incubation temperature from 35.0 to 36.7°C decreased the incubation period by 3 days.…”

The white colour of the Ostrich (Struthio camelus) egg is a trade-off between predation and overheating

“…An estimate of the upper thermal tolerance for short-time exposure in most species is 41°C, and for exposures lasting several hours it is 39°C (Webb 1987). In Ostriches, increased embryo mortality is reported at temperatures above 37.5°C (Hassan et al 2004;Ipek et al 2003) and reduced hatching success is reported at temperatures above 40°C (Deeming et al 1993). The high core temperatures of brown-painted eggs observed in this experiment (Fig.…”

“…The optimum temperature for Ostrich egg incubation is 36.0-36.5°C (e.g. Deeming 1993; Hassan et al 2004), and incubation temperatures above 37.5°C increase the incidence of dead embryos (Hassan et al 2004). …”

Dating North Asian surface assemblages with ostrich eggshell: implications for palaeoecology and extirpation

“…African ostriches obtain most moisture from their food and tolerate low temperatures, but drinking is important to sub-adults and newly hatched chicks are unable to thermoregulate (Brown and Prior, 1999). Industrial incubation studies indicate the importance of controlling necessary egg water loss and avoiding temperatures below 36 C (Hassan et al, 2004). The larger size of Struthio anderssoni eggs compared to S. camelus (Lowe, 1931) suggests increased egg and body size as a cold adaptation.…”