Effect of Short-Term Feed Restriction on Production Traits of Brown and Black Plumage Commercial Layer Strains at Late Phase of Egg Production

Abstract

The effect of strain and different levels of quantitative feed restriction for short time (28d) on egg production, feed consumption and efficiency, mortality and egg quality traits were evaluated during late phase of egg laying. A total number of 90 layers aged 54 weeks old, comprising 45 birds each of Isa Brown (brown plumage) and Bovan Black (black plumage) were randomly distributed into three treatment groups having three replicates each. They were placed under three feeding regimens namely, T1 (ad libitum- control), T2 (90% ad libitum) and T3 (80% ad libitum). Data collected include egg production, mortality, feed variables, external and internal egg quality characteristics. The results revealed that strain has insignificant (P>0.05) effect on egg numbers during the 28 days trial regardless of treatments imposed. This means that feed restriction on short-term has no negative impact on both the brown and black feathered layer birds productivity. However, feed restriction has significant (P<0.01) effect on both egg numbers and hen-day egg production regardless of strain of birds. Regarding the two traits, ad libitum (control) and 90% ad libitum had similar mean values, but higher than 80% ad libitum. As per feed efficiency, brown strain has higher (P<0.01) mean values than the black strain. The two strains subjected to feed restriction recorded similar mean values and performed equally well in egg weight, egg length and other external and internal egg qualities. However, in albumen height and Haugh unit (HU), brown birds had higher (P<0.01) mean values than black hens. Haugh unit is a measure of internal egg quality. The highest net revenue/hen and economic efficiency was recorded in 90% ad libitum ($1.19, 112.26), intermediate ($1.06, 100) in ad libitum and lowest (1.10, 95.28) in 80% ad libitum. Brown strain achieved higher (P<0.01) economic efficiency (100 vs 88.54) and net revenue ($0.96 vs $0.85) per hen than black strain at the end of the experimental period. There was significant strain x treatment interaction effect on egg number, percent egg production and feed variables. Brown feathered birds and adoption of milder feed restriction seem to hold prospect for increased production, profit and sustainability of egg producing industry.