Poultry International - January 2016 - 26

26 ❙ PoultryInternational

4 tips to improve eggshell
resistance in aging layers
Eggshell resistance is naturally reduced as layers age, but there are
means to alleviate the impact of metabolic fatigue through nutritional
intervention.
IOANNIS MAVROMICHALIS

A

Aging hens produce larger, albeit more fragile, eggs.
Cracked eggs among older hens can exceed 20 percent,
and these eggs are a negative mark for the egg industry
for obvious reasons.

1. Calcium absorption
The main reason why older layers produce more
cracked eggs has to do with egg size. As they deposit
a fixed amount of calcium per egg (2 grams), and calcium is the main element that provides strength to the
shell, it is expected for a larger egg to have a thinner
shell. With age, calcium digestibility and metabolism
are impaired, while adding excessive amounts of dietary calcium only makes things worse. To this end,
enhancing calcium digestibility and absorption appears
to be a viable alternative. Thus, adding a more digest-

Egg size plays a significant role in eggshell quality,
especially among older layers.

Andrea Gantz

ible source or form of calcium is recommended for
diets during the last phase of egg production . In addition, adding organic acids and extra vitamin D have
been shown to further improve the calcium balance
and consequently egg shell quality.

2. Phosphorus and phytase
Phosphorus is the second most influential mineral
regarding eggshell quality. Here, the effect of this mineral can be antagonistic to that of calcium, as too much
dietary phosphorus reduces intestinal calcium absorption. Thus, most layer diets tend to have low levels of
phosphorus, but this can cause its own problems: it has
been reported that when phytase is part of the phosphorus equation, then the already marginal dietary
phosphorus levels can become limiting if phytase efficacy is impaired. How this might relate to older hens
is still unknown.

3. Vitamin D and metabolites
Vitamin D is part of the calcium-phosphorus homeostasis within the organism. Thus, high levels of
dietary vitamin D can positively influence eggshell
quality. Nevertheless, there is a natural bottleneck in
vitamin D metabolism, which can be bypassed by using an active metabolite of vitamin D, instead of or in
addition to the usual form. As this bottleneck becomes
even more limiting in aging hens, better results are expected when using an active metabolite - but this has
not been unequivocally confirmed.
www.WATTAgNet.com ❙ January 2016


http://www.WATTAgNet.com

Table of Contents for the Digital Edition of Poultry International - January 2016

Contents
Poultry International - January 2016 - Cover1
Poultry International - January 2016 - Cover2
Poultry International - January 2016 - Contents
Poultry International - January 2016 - 2
Poultry International - January 2016 - 3
Poultry International - January 2016 - 4
Poultry International - January 2016 - 5
Poultry International - January 2016 - 6
Poultry International - January 2016 - 7
Poultry International - January 2016 - 8
Poultry International - January 2016 - 9
Poultry International - January 2016 - 10
Poultry International - January 2016 - 11
Poultry International - January 2016 - 12
Poultry International - January 2016 - 13
Poultry International - January 2016 - 14
Poultry International - January 2016 - 15
Poultry International - January 2016 - 16
Poultry International - January 2016 - 17
Poultry International - January 2016 - 18
Poultry International - January 2016 - 19
Poultry International - January 2016 - 20
Poultry International - January 2016 - 21
Poultry International - January 2016 - 22
Poultry International - January 2016 - 23
Poultry International - January 2016 - 24
Poultry International - January 2016 - 25
Poultry International - January 2016 - 26
Poultry International - January 2016 - 27
Poultry International - January 2016 - 28
Poultry International - January 2016 - 29
Poultry International - January 2016 - 30
Poultry International - January 2016 - 31
Poultry International - January 2016 - 32
Poultry International - January 2016 - 33
Poultry International - January 2016 - 34
Poultry International - January 2016 - 35
Poultry International - January 2016 - 36
Poultry International - January 2016 - 37
Poultry International - January 2016 - 38
Poultry International - January 2016 - 39
Poultry International - January 2016 - 40
Poultry International - January 2016 - 41
Poultry International - January 2016 - 42
Poultry International - January 2016 - 43
Poultry International - January 2016 - 44
Poultry International - January 2016 - 45
Poultry International - January 2016 - 46
Poultry International - January 2016 - 47
Poultry International - January 2016 - 48
Poultry International - January 2016 - 49
Poultry International - January 2016 - 50
Poultry International - January 2016 - 51
Poultry International - January 2016 - 52
Poultry International - January 2016 - Cover3
Poultry International - January 2016 - Cover4
https://www.poultryinternational-digital.com/202002
https://www.poultryinternational-digital.com/202001
http://www.poultryinternational-digital.com/201912
http://www.poultryinternational-digital.com/201911
http://www.poultryinternational-digital.com/201910
http://www.poultryinternational-digital.com/201909
http://www.poultryinternational-digital.com/201908
http://www.poultryinternational-digital.com/201907
http://www.poultryinternational-digital.com/201906
http://www.poultryinternational-digital.com/201905
http://www.poultryinternational-digital.com/201904
http://www.poultryinternational-digital.com/201903
http://www.poultryinternational-digital.com/201902
http://www.poultryinternational-digital.com/201901
http://www.poultryinternational-digital.com/201812
http://www.poultryinternational-digital.com/201811
http://www.poultryinternational-digital.com/201810/
http://www.poultryinternational-digital.com/201809/
http://www.poultryinternational-digital.com/201808/
http://www.poultryinternational-digital.com/201807/
http://www.poultryinternational-digital.com/201806/
http://www.poultryinternational-digital.com/201805/
http://www.poultryinternational-digital.com/201804/
http://www.poultryinternational-digital.com/201803/
http://www.poultryinternational-digital.com/201802/
http://www.poultryinternational-digital.com/201801/
http://www.poultryinternational-digital.com/201712/
http://www.poultryinternational-digital.com/201711/
http://www.poultryinternational-digital.com/201710/
http://www.poultryinternational-digital.com/201709/
http://www.poultryinternational-digital.com/201708/
http://www.poultryinternational-digital.com/201707/
http://www.poultryinternational-digital.com/201706/
http://www.poultryinternational-digital.com/201705/
http://www.poultryinternational-digital.com/201704/
http://www.poultryinternational-digital.com/201703/
http://www.poultryinternational-digital.com/201702/
http://www.poultryinternational-digital.com/201701/
http://www.poultryinternational-digital.com/201612/
http://www.poultryinternational-digital.com/201611/
http://www.poultryinternational-digital.com/201610/
http://www.poultryinternational-digital.com/201609
http://www.poultryinternational-digital.com/201608
http://www.poultryinternational-digital.com/201607
http://www.poultryinternational-digital.com/201606
http://www.poultryinternational-digital.com/201605
http://www.poultryinternational-digital.com/201604
http://www.poultryinternational-digital.com/201603
http://www.poultryinternational-digital.com/201602
http://www.poultryinternational-digital.com/201601
http://www.poultryinternational-digital.com/201512
http://www.poultryinternational-digital.com/201511
http://www.poultryinternational-digital.com/201510
http://www.poultryinternational-digital.com/201509
http://www.poultryinternational-digital.com/201508
http://www.poultryinternational-digital.com/201507
http://www.poultryinternational-digital.com/201506
http://www.poultryinternational-digital.com/201505
http://www.poultryinternational-digital.com/201504
http://www.poultryinternational-digital.com/201503
http://www.poultryinternational-digital.com/201502
http://www.poultryinternational-digital.com/201501
http://www.poultryinternational-digital.com/201412
http://www.poultryinternational-digital.com/201411
http://www.poultryinternational-digital.com/201410
http://www.poultryinternational-digital.com/201409
http://www.poultryinternational-digital.com/201408
http://www.poultryinternational-digital.com/201407
http://www.poultryinternational-digital.com/201406
http://www.poultryinternational-digital.com/201405
http://www.poultryinternational-digital.com/201404
http://www.poultryinternational-digital.com/201403
http://www.poultryinternational-digital.com/201402
http://www.poultryinternational-digital.com/201401
http://www.poultryinternational-digital.com/201312
http://www.poultryinternational-digital.com/201311
http://www.poultryinternational-digital.com/201310
http://www.poultryinternational-digital.com/201309
http://www.poultryinternational-digital.com/201308
http://www.poultryinternational-digital.com/201307
http://www.poultryinternational-digital.com/201306
http://www.poultryinternational-digital.com/201305
http://www.poultryinternational-digital.com/201304
http://www.poultryinternational-digital.com/201303
http://www.poultryinternational-digital.com/201302
http://www.poultryinternational-digital.com/201301
http://www.poultryinternational-digital.com/201212
http://www.poultryinternational-digital.com/201211
http://www.poultryinternational-digital.com/201210
http://www.poultryinternational-digital.com/201209
http://www.poultryinternational-digital.com/201208
http://www.poultryinternational-digital.com/201207
http://www.poultryinternational-digital.com/201206
http://www.poultryinternational-digital.com/201205
http://www.poultryinternational-digital.com/201204
http://www.poultryinternational-digital.com/201203
http://www.poultryinternational-digital.com/201202
http://www.poultryinternational-digital.com/201201
http://www.nxtbookMEDIA.com