No abstract

Effect of extended storage on egg quality, embryo mortality and hatchability in FUNAAB‐ɑ chickens was determined. Hatchable eggs (n = 288; weighing 53.2 ± 4.67 g) collected from a flock of FUNAAB‐ɑ layer breeder hens aged 32 weeks were stored in egg tray with broad end up under 16 ± 1.5°C for either 0, 4, 8, 12, 16 or 20 d. Before incubation, eight eggs from each group were evaluated for internal and external quality traits. Remaining eggs were set in an incubator and transferred into hatcher on embryonic day 18. Data collected were subjected to one‐way analysis of variance. Egg weight loss (EWL; p < .001), surface area (p < .001), yolk diameter (p < .001), inner and outer blastoderm diameters (p < .05) and dead in germ (DIG; p < .001) increased with storage duration while yolk height (p < .001), yolk index (p < .001), albumen weight (p < .05), albumen height (p < .05), albumen index (p < .01), Haugh's unit (HU; p < .05), fertility (p < .001), hatchability of set (HATCHS; p < .001) and fertile eggs (p < .05) decreased. Weight losses of 0, 1.2, 2.2, 3.4, 4.6 and 6.1% were recorded in egg stored for 0, 4, 8, 12, 16 and 20 days respectively. Eggs stored beyond 8 days exhibited higher DIG and lower HATCHS. Shell percentage in 4 days storage (11.4%) was lower (p < .05) than in 16 days storage (13.4%). Shell thickness was similar in eggs stored for 0 to 12 days, but 8 days storage (0.60 mm) had thinner (p < .01) shell than day 16 (0.71 mm) and day 20 (0.73 mm) storage. Internal quality unit (IQU) was higher (p < .05) in fresh eggs (180.4) than in 12 days (167.8) and 20 days (167.8) stored eggs. Extended storage of FUNAAB‐ɑ eggs caused EWL, surface area shrinkage, lowered HU and IQU, loss of yolk and albumen quality, increased blastoderm diameters and DIG, and decreased egg fertility and HATCHS from day 8 forward. Storing FUNAAB‐ɑ eggs beyond 8 days reduced quality parameters; therefore, other mitigating factors are recommended when storing beyond 8 days.

No abstract

The effects of heat stress on several aspects of animal production are well documented. Heat stress results from the animal's inability to dissipate sufficient heat to maintain homeothermy. High ambient temperature, relative humidity, and radiant energy compromise the ability of animals to dissipate heat. As a result, there is an increase in body temperature, which in turn initiates compensatory and adaptive mechanisms to re-establish homeothermy and homeostasis. Heat stress could affect animal production and well-being, especially because of increase in air temperature. Heat stress is very common and on the increase particularly in the tropics. There is considerable research evidence that shows significant decline in animal performance when subjected to heat stress. Heat stress inflicts heavy economic losses on livestock production. The effects of heat stress is evident in feed consumption, production efficiency in terms of milk yield or weight gain per unit of feed energy, growth rate, egg production, and reproductive efficiency. The physiologic mechanisms underlying the action of heat stress on the decline of production performance of domestic animals have not been fully investigated. Heat stress requires further investigation, and the elucidation of the mechanisms may facilitate adoption of comprehensive preventive and control measures to combat heat stress in domestic animals. This chapter examines heat stress and its negative impacts on livestock production. It elucidates the general negative effects of heat stress on physiologic and production parameters of domestic livestock. The mechanisms involved when animals are subjected to heat stress and impacts of heat stress on domestic animals are emphasized. An understanding of these mechanisms may result in the development of improved techniques for enhancing livestock productivity in tropical environments.

Growing broilers were offered either 0 (0H), 10 (10H), 20 mL (20H) honey, or 0.5 g vitamin C/litre water (AA) during hot-dry season. Honey had no significant (P > 0.05) effect on feed intake (FI), weight gain (WG), feed conversion ratio (FCR), water intake (WI), survival (SURV), dressed percentage (DRE), breas tmeat (BRE), gizzard (GIZ), drumstick (DRU), shank (SHA), thigh (THI), tibia volume (VOL), and magnesium (MAG). Effect of honey was significant (P < 0.05) on tibial weight (WEI), density (DEN), calcium (CAL), and phosphorus (PHO). WEI and DEN increased with increasing level of honey. 20H broilers had higher CAL than 0H and 10H groups. Broilers offered honey had significantly lower PHO than AA group but the difference between honey groups was not significant. Honey significantly affected PR (P < 0.001) and HR (P < 0.001) but not RT (P > 0.005). Higher dose of honey lowered PR and HR. Honey significantly (P < 0.05) increased THY but LIV, KID, LUN, SPL, BUR, and HEA were not significantly (P > 0.05) affected. 20H broilers had higher THY than 0H and 10H groups. In conclusion, honey did not affect growth but might improve broilers' welfare when offered up to 20H during hot periods.