Reproduction in Birds- research and practical significance

Question 1

visible light to chickens

Answer 1

360-760 nm (a little bit into UV through to infrared)

Question 2

Visual Stimulation

Answer 2

Photosensitive pigments (Opsins) excited by specific light wavelengths

Question 3

Three organs with photoreceptors

Answer 3

1. Eye (retina):Uv, blue, green, red opsins to brain via optic nerve
2. Pineal Gland: on top of Brain, produces melatonin, has piano-sin: hybrid between rhodopsin and green opsin
3. Hypothalamus: deep brain tissue, lots of opsins specific to various wavelengths but light needs to penetrate

Question 4

Initial Research

Answer 4

effect of light wavelength on reproduction- retinal vs extra retinal photoreceptors

Question 5

experimental setup

Answer 5

• 3 optically isolated sections with LED strip lights (red, white, green)
• intensities adjusted 10 lux at hens levels
• smokey Joe hens (blind and sighted) used to evacuate the role of the retina in the eye
• at 15 weeks, LEDs lights on–> 8h photoperiod
• at 20 weeks, photostim with a 14 h photoperiod

Question 6

effects of treatments on sexual maturation

Answer 6

green light treatment delayed maturation
no significant difference between white and red light

red light is beneficial
green is detrimental

Question 7

Design of an LED bulb for layers

Answer 7

in collaboration with Thies electrical distributing inc.
our recommendations
- 60% red (20% green, 20% blue)
- dimmable without loss of spectrum
able to handle fluctuations in power
- able to handle fluctuations in power
- able to handle cleaning and disinfection
- low cost to install (easy barn retrofit)

Question 8

Field Trial

Answer 8

setting

• birds 42,000 hens
• Lehman LSL lite

barn

• enrich able colony cages, 6 rows, 3 tiers
• blackouts on the vents
• pigtail lighting

timeline

• two flocks
• 51 weeks

Question 9

potential gains from egg production

Answer 9

2% increase on flock average over a 51 week period
with a 42,000 hen flock, gain of approx 271,000 total eggs
at $2.00 paid per dozen, this can provide potential returns of $45,311
potential savings $`2,519 in electricity costs

Question 10

improvement in layers over the years

Answer 10

eggs production has more than doubled over the last 50 years (from 150 to >330)

commercial lines are now expected to remain above 90% production throughout at 52 week cycle

unselected layers(smokey Joe) peak production around 80%

lohmann LSL modern commercial line peak at 100%
- start laying before photo stimulation

Question 11

Intensive genetic selection has impaired the control of reproduction

Answer 11

early entry into lay regardless of photoperiod –> metabolic cue??
extended peak of lay (over 90% throughout year

Question 12

extended laying persistency

Answer 12

breeders stated a goal is to create a layer hen that can produce over 500 eggs by 100 weeks of age

Question 13

Pullet stage is critical

Answer 13

need to accumulate all the reserves necessary to sustain an extended lay- especially Ca
selection for early lay –> smaller birds
if the bird grows faster than its skeleton:
- metabolic signal triggers entry into lay
- medullary bone not mature= osteoporosis toward the end of lay

if the bird grows too slowly

• skeleton may he ready
• metabolic cues absent: small eggs, poor response to photo stimulation

Question 14

Meat Birds

Answer 14

heavily selected for fast growth, especially muscle deposition
parent stock, broiler breeders, have the same genetics and, unchecked growth impacts reproduction

• leg problems
• mating problems
• obesity related issues