The document discusses factors that affect embryo temperature during incubation. It finds that machine temperature does not equal embryo temperature, as embryo temperature depends on a balance between heat production and heat loss. Heat production is influenced by developmental stage, physical traits, biological traits like breed and egg size, and environmental factors like oxygen levels. Heat loss depends on evaporation, which is affected by humidity and air temperature, and heat transfer, which depends on temperature differences, air properties, and velocity. Maintaining a constant eggshell temperature close to 37.8°C is important for optimal embryo development.
2. Incubation through the embryos point of view Sander Lourens (researcher poultry health & welfare) Bas Kemp (professor at Wageningen University) Henry van den Brand (Lecturer at Wageningen University) Marcel Heetkamp (Technician at Wageningen University) Ron Meijerhof (Hybro B.V., now at HatchBrood B.V.)
34. CL BW YFB RY HW LW HT (cm) (g) (g) (g) (g) (g) (d) EST 37.8°C 19.7 41.5 a 37.4 a 4.0 0.40 a 1.65 a 20.5 a 38.9°C 19.8 39.8 b 35.8 b 4.0 0.33 b 1.53 b 19.8 b O2 17% 19.0 c 40.6 35.3 b 5.3 a 0.36 1.49 20.2 21% 19.9 b 40.6 36.9 a 3.7 b 0.35 1.63 20.2 25% 20.4 a 40.7 37.7 a 3.0 c 0.38 1.65 20.2 EST NS * * NS ** * ** O2 ** NS * ** NS NS NS ESTxO2 NS NS NS NS NS NS NS
38. Energy utilization, efficiency of energy transfer between egg and hatchling (E YFB ). After Lourens et al. (unpublished). 152 a 138 b 119 c 148 a 131 b HP at d18 (mW.egg -1 ) 52.4 54.9 52.5 50.8 b 55.7 a E YFB (%) 326 a 313 b 286 c 311 305 Utilized (kJ) 31 c 43 b 68 a 46 48 RY (kJ) 171 a 172 a 150 b 158 b 170 a YFB (kJ) 281 281 282 282 280 Yolk (kJ) 76 75 73 76 73 Albumen (kJ) 25% 21% 17% 38.9 o C 37.8 o C O 2 EST
39. Table 4. Factors affecting HP through energy utilization and efficiency of energy transfer between egg and hatchling (E YFB ) Factors affecting HP through energy utilization and efficiency of energy transfer between egg and hatchling (E YFB ). After Lourens et al. (unpublished) Yes No Eggshell temperature No Yes Oxygen No Yes Breed No Yes Egg weight E YFB Energy utilization
40. Environmental factors O 2 heat CO 2 H 2 O + + Concentration Air pressure Altitude Eggshell conductance Oxygen availability to the embryo (red blood cells)
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44. Eggshell temperature is the key!!! To know EST, you have to measure it Keep EST close to 37.8 o C constantly Take home message: