Effects of Stocking Density and Group Size on Thermoregulatory Responses of Laying Hens under Heat-Challenging Conditions

dc.contributor.author Green, Angela
dc.contributor.author Xin, Hongwei
dc.contributor.author Xin, Hongwei
dc.contributor.department Agricultural and Biosystems Engineering
dc.date 2018-02-13T04:18:09.000
dc.date.accessioned 2020-06-29T22:37:41Z
dc.date.available 2020-06-29T22:37:41Z
dc.date.copyright Thu Jan 01 00:00:00 UTC 2009
dc.date.embargo 2012-12-13
dc.date.issued 2009-01-01
dc.description.abstract <p>Sectors of the U.S. cage layer industry have begun adopting practices of reduced stocking density (i.e., increased cage floor space per hen) and varying group sizes. This study was conducted with 24 groups of 48 W-36 laying hens (39 to 46 weeks old) to assess the effects of cage floor space or stocking density (SD) (348, 387, 465, or 581 cm2 hen-1; 54, 60, 72, or 90 in.2 hen-1) and group size (GS) (8 or 16 hens per cage) on the ability of the hens to cope with heat challenge. Data were collected at thermoneutral (24°C or 76°F) and warm conditions (32°C or 90°F, followed by 35°C or 95°F). No differences in core body temperature (CBT) of the hens were observed among the treatment regimens at 24°C. In general, mean CBT increased with heat exposure duration (P < 0.0001) but leveled off after the 32°C phase. At 32°C, CBT was higher for GS of 16 vs. 8 (42.3°C vs. 42.1°C, P = 0.05) and higher for SD of 348 and 387 cm2 hen-1 than for 465 or 581 cm2 hen-1 (42.4°C and 42.2°C vs. 41.9°C and 42.1°C, respectively, P = 0.009). Bird body mass decreased as heat exposure duration increased (P < 0.0001), but no differences were observed among the treatments. No mortalities were observed during the thermoneutrality period, and the mortality rate increased with heat exposure duration. The results indicate that, while CBT was lower for lower SD, the increased space was not sufficient to offer a clear benefit for coping with heat challenge of 32°C followed by 35°C.</p>
dc.description.comments <p>This article is from <a href="http://elibrary.asabe.org/abstract.asp?aid=29205&t=3&dabs=Y&redir=&redirType=" target="_blank"><em>Transactions of the ASABE</em></a> 52, no. 6 (2009): 2033–2038.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/abe_eng_pubs/173/
dc.identifier.articleid 1168
dc.identifier.contextkey 3536196
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath abe_eng_pubs/173
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/911
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/abe_eng_pubs/173/Xin_2009_EffectsStocktingDensityGroupSizeThermoregulatory.pdf|||Fri Jan 14 21:19:56 UTC 2022
dc.subject.disciplines Agriculture
dc.subject.disciplines Bioresource and Agricultural Engineering
dc.subject.keywords Caged layer
dc.subject.keywords Core body temperature
dc.subject.keywords Heat stress
dc.subject.keywords Production
dc.subject.keywords Welfare
dc.title Effects of Stocking Density and Group Size on Thermoregulatory Responses of Laying Hens under Heat-Challenging Conditions
dc.type article
dc.type.genre article
dspace.entity.type Publication
relation.isAuthorOfPublication 36e0a8ce-fa2e-4df4-9f67-8d1717122650
relation.isOrgUnitOfPublication 8eb24241-0d92-4baf-ae75-08f716d30801
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