The leg strength of two commercial strains of meat chicken subjected to different incubation profiles

Lower egg shell temperatures (EST) during the first 2 weeks of incubation, notionally known as Slow start incubation, extended the standing time of a 5-week-old fast feathering meat chicken parent line. This study was designed to evaluate the effect of Slow start incubation on the standing ability o...

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Main Authors: W.I. Muir, P.J. Groves
Format: Article
Language:English
Published: Elsevier 2019-01-01
Series:Animal
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S1751731118002999
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author W.I. Muir
P.J. Groves
author_facet W.I. Muir
P.J. Groves
author_sort W.I. Muir
collection DOAJ
description Lower egg shell temperatures (EST) during the first 2 weeks of incubation, notionally known as Slow start incubation, extended the standing time of a 5-week-old fast feathering meat chicken parent line. This study was designed to evaluate the effect of Slow start incubation on the standing ability of commercial meat chickens. Eggs from two strains of meat chickens, Strains 1 and 2, were incubated using either the Slow start incubation, (the initial EST was 36.75°C followed by a gradual increase in EST, reaching 37.8°C at day 16 of incubation), or Control incubation (EST 37.75°C to 38°C from the start of incubation until day 18 of incubation). Eggs were observed every 6 h from 468 h until 516 h of incubation to identify chick hatch window. At 516 h of incubation all chicks were taken out of the incubator (take-off). Chicks from each Strain and incubation treatment were randomly selected for assessment of chick weight, chick length, yolk sac weight, serum Ca and P, and femoral bone ash (BA). All unhatched eggs were inspected to determine the stage of embryo failure. Remaining chicks were grown for 5 weeks in floorpens. Weekly feed intake (FI), chick weight and feed conversion ratio (FCR) were determined. At 35 days of age the standing ability of visibly male birds was assessed in a latency-to-lie test. Compared to the Control, Slow start incubation delayed the average hatch time of both strains by ∼13 h, and reduced hatchability with 4.6% live but unhatched chicks, which was most evident in Strain 2. Significant differences due to main effects only were observed at take-off. Strain 1 chicks were significantly heavier and longer with higher serum Ca but significantly lower BA and serum P than Strain 2. Slow start incubation generated significantly heavier chicks that were shorter, but had significantly heavier yolk sacs, lower serum Ca but higher serum P than Control incubated chicks. During the 1st week post hatch Strain 1 Control incubated chicks had significantly higher FI and higher FCR than all other Strain and incubation treatments. At 35 days of age Slow start incubated birds of both Strains stood significantly longer than those from the Control incubation. This experiment clearly demonstrated the ability of Slow start incubation of commercial meat chickens to improve their leg strength.
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spelling doaj.art-9c125e7ded5f438d86473a6c329835972022-12-21T22:51:26ZengElsevierAnimal1751-73112019-01-0113714891497The leg strength of two commercial strains of meat chicken subjected to different incubation profilesW.I. Muir0P.J. Groves1School of Life and Environmental Science, Poultry Research Foundation, Faculty of Science, The University of Sydney, Camden, NSW 2570, AustraliaSydney School of Veterinary Science, Poultry Research Foundation, Faculty of Science, The University of Sydney, Camden, NSW 2570, AustraliaLower egg shell temperatures (EST) during the first 2 weeks of incubation, notionally known as Slow start incubation, extended the standing time of a 5-week-old fast feathering meat chicken parent line. This study was designed to evaluate the effect of Slow start incubation on the standing ability of commercial meat chickens. Eggs from two strains of meat chickens, Strains 1 and 2, were incubated using either the Slow start incubation, (the initial EST was 36.75°C followed by a gradual increase in EST, reaching 37.8°C at day 16 of incubation), or Control incubation (EST 37.75°C to 38°C from the start of incubation until day 18 of incubation). Eggs were observed every 6 h from 468 h until 516 h of incubation to identify chick hatch window. At 516 h of incubation all chicks were taken out of the incubator (take-off). Chicks from each Strain and incubation treatment were randomly selected for assessment of chick weight, chick length, yolk sac weight, serum Ca and P, and femoral bone ash (BA). All unhatched eggs were inspected to determine the stage of embryo failure. Remaining chicks were grown for 5 weeks in floorpens. Weekly feed intake (FI), chick weight and feed conversion ratio (FCR) were determined. At 35 days of age the standing ability of visibly male birds was assessed in a latency-to-lie test. Compared to the Control, Slow start incubation delayed the average hatch time of both strains by ∼13 h, and reduced hatchability with 4.6% live but unhatched chicks, which was most evident in Strain 2. Significant differences due to main effects only were observed at take-off. Strain 1 chicks were significantly heavier and longer with higher serum Ca but significantly lower BA and serum P than Strain 2. Slow start incubation generated significantly heavier chicks that were shorter, but had significantly heavier yolk sacs, lower serum Ca but higher serum P than Control incubated chicks. During the 1st week post hatch Strain 1 Control incubated chicks had significantly higher FI and higher FCR than all other Strain and incubation treatments. At 35 days of age Slow start incubated birds of both Strains stood significantly longer than those from the Control incubation. This experiment clearly demonstrated the ability of Slow start incubation of commercial meat chickens to improve their leg strength.http://www.sciencedirect.com/science/article/pii/S1751731118002999egg shell temperaturehatch windowbroilerbone ashlatency-to-lie
spellingShingle W.I. Muir
P.J. Groves
The leg strength of two commercial strains of meat chicken subjected to different incubation profiles
Animal
egg shell temperature
hatch window
broiler
bone ash
latency-to-lie
title The leg strength of two commercial strains of meat chicken subjected to different incubation profiles
title_full The leg strength of two commercial strains of meat chicken subjected to different incubation profiles
title_fullStr The leg strength of two commercial strains of meat chicken subjected to different incubation profiles
title_full_unstemmed The leg strength of two commercial strains of meat chicken subjected to different incubation profiles
title_short The leg strength of two commercial strains of meat chicken subjected to different incubation profiles
title_sort leg strength of two commercial strains of meat chicken subjected to different incubation profiles
topic egg shell temperature
hatch window
broiler
bone ash
latency-to-lie
url http://www.sciencedirect.com/science/article/pii/S1751731118002999
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