Relationships of Incubational Hatching Egg Characteristics to Post-hatch Bodyweight and Processing Yield in Broilers17 March 2014
After examining the relationships between hatching egg characteristics during incubation and subsequent growth and processing yield in a modern broiler strain, researchers in the US recommend monitoring of mean daily percentage of incubational weight loss, especially during the first half of the incubation period.
The characteristics of broiler hatching eggs have the potential to effect broiler post-hatch growth and processing yield, according to D. Peebles of Mississippi State University and co-authors there and at Clemson University in a paper published in Journal of Applied Poultry Research.
They investigated the association of set egg weight (SEW), length of incubation (LI) and mean daily percentage of incubational weight loss (MDPEWL) of embryonated Ross × Ross 708 broiler hatching eggs with subsequent post-hatch bodyweight and processing yield.
Sixty Ross × Ross 708 broiler hatching eggs were randomly set on each of eight replicate tray levels of an incubator.
Weight loss of individual embryonated eggs between 0 and 10.5, 10.5 and 18.5 and 0 and 18.5 days of incubation was determined for the calculation of MDPEWL. Furthermore, on 18.5 day of incubation, embryonated eggs were transferred to a hatcher unit where they were individually monitored for hatch every 12 hours for determination of LI.
Chicks were placed in corresponding replicate floor pens and were grown out from 0 (21.5 days of incubation) to 49 days post-hatch.
Live bird bodyweight as a percentage of SEW on 21.0 days of incubation and days 0 and 49 post-hatch, and bird sex on day 49 post-hatch were determined.
After commercial processing, carcass weight as a percentage of SEW, and carcass, abdominal fat pad, wings, breast muscle, tenders, drumsticks and thighs weights as percentages of live bodyweight were determined.
Bird bodyweight on 21.0 days of incubation and on days 0 and 49 post-hatch were positively correlated or interrelated with SEW.
Between 0 and 10.5 days of incubation, MDPEWL was negatively correlated with absolute and relative bodyweight on 21.0 days of incubation, absolute bodyweight on day 0 post-hatch and relative tenders weight.
LI was positively correlated with absolute and relative bodyweight on 21.0 days of incubation and day 0 post-hatch but was negatively correlated with relative (percentage of live bodyweight) carcass weight on day 49 post-hatch.
Peebles and co-authors recommend that the MDPEWL of modern strain broiler hatching eggs should be closely monitored, particularly during the first half of incubation, for the regulation of LI and hatchling bodyweight and for their potential effects on processing yield characteristics.
Peebles E.D., R. Pulikanti, W. Zhai and P.D. Gerard. 2014. Relationships of incubational hatching egg characteristics to posthatch body weight and processing yield in Ross × Ross 708 broilers. J. Appl. Poult. Res. 23(1):34-40. doi: 10.3382/japr.2013-00784
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