Yolk sac utilization in ostrich (<i>Struthio camelus<i/>) chicks : research communication

Abstract

The mass of residual yolk sac expressed as a percentage of initial mass of the egg from which the chick hatched decreased sharply in the first 2 days post-hatching. A gradual reduction occurred between 3 and 10 days after which a sharp decline was noted between 11 and 13 days post-hatching. The highest number of chicks with unabsorbed yolk sac was noted on day 5 post-hatching followed by days 6 and 7. Chick mortality followed the same pattern. The dynamics, causes and clinical consequences of yolk sac utilization are discussed.

The composition of egg yolk absorbed by fasted ostrich (Struthio camelus L.) chicks from 1 to 7 days posthatching and for ostrich (Struthio camelus L.) chicks from 1 to 16 days posthatching on a prestarter broiler diet

“…There was no difference in the hatching weight between individual chicks {P = 0.56; Table 1) although the average hatching weight was much lower than that reported in previous studies that ranged from 1.4 to 1.6 kg (Keffen and Jarvis, 1984;Mushi et al, 2004). This discrepancy may be due to the inherent characteristics of the particular eggs that were sourced for the trial.…”

“…In contrast, this trial indicated that ostrich chicks only absorb 30% of the yolk over the first 4 d posthatch, 67% after 8 d posthatch, and only deplete the yolk reserve after 14 d posthatch. This observation is supported by the study of Mushi et al (2004) on ostrich chicks that suggested yolk reserves were considered retained beyond 13 d posthatch.…”

“…The trial continued for 16 d, as it had been reported that yolk was still present in 12-d-old chicks (Mushi et al, 2004). Chicks were kept under similar conditions to those used in the first trial, except for the provision of a poultry prestarter diet (AFCRI Animal Feeds, South Africa).…”

“…It was concluded that yolk utilization was more efficient in chicks that received feed and water after hatching, and that starvation has a negative effect on the development of the digestive tract and digestive enzymes. Much less work has been done on yolk utilization in ostrich chicks (Bertram and Burger, 1981;Deeming, 1995;Mushi et al, 2004), especially with regard to the influence of feeding and starvation on yolk utilization.…”

Ultrasonographic features of the regressing yolk sac of normal captive Brown kiwi chicks (Apteryx mantelli) vary with age

“…Normal yolk sac resorption and diseases of the yolk sac have been studied in other avian species. 6,10,11,12,13,14 Currently there are varying reports of the normal length of time for yolk sac utilization, ranging from 4 to 15 days, with precocial species such as the ostrich (Struthio camelus) being at the higher end of this range. 6,12,15,16 Of all birds, kiwi lay the biggest eggs relative to their size (ca.…”