Effect of Scavenging and Protein Supplement on the Feed Intake and Performance of Improved Pullets and Laying Hens in Northern Vietnam

Abstract

Two feeding trials were conducted with 128 pullets from 4 to 20 weeks of age and 96 laying hens from 23 to 63 weeks of age to evaluate the effects of scavenging and type of protein supplement on the feed intake and performance of improved pullets and laying hens. The experiments had a completely randomized design with four dietary treatments and four replicates. Treatments were: Control (Cont), scavenging but with access to a balanced concentrate at night; confinement (CF) and given the control feed ad libitum; scavenging and supplemented at night with the control feed, but with soybean meal replaced by cassava leaf meal (CLM); scavenging and supplemented at night with the control feed, but with fishmeal replaced by soybean meal (SBM). The mean daily dry matter (DMI), metabolizable energy (MEI) and crude protein intakes (CPI) of the pullets and laying hens, respectively, were 28%, and 18% higher for the confinement treatment (CF) compared to the scavenging treatments (p<0.001). The DMI, MEI and CPI of the pullets were not significantly different among scavenging treatments (p>0.05), but for the layers DMI, MEI and CPI were significantly higher for the CLM and SBM treatments compared to the Cont treatment (p<0.001). In the growing period, the average daily weight gain (ADG), supplement feed conversion ratio (FCR) and supplement feed cost/kg eggs (FCS) were not significantly different for CF compared to Cont, and among scavenging treatments (p>0.05). In the laying period, the hen-day production was significantly lower, and supplement FCR and FCS significantly higher for the CF compared to the scavenging treatments (p<0.001). Egg weight, and yolk, albumen and shell percentage and shape index were not significantly different among the scavenging treatments (p>0.05). However, shell and yolk percentages were significantly lower for the CF compared to the Cont treatment (p<0.01). Mortality was significantly higher for the CF compared to the scavenging treatments for pullets, and was significantly lower for the CF compared to scavenging treatments for laying hens (p<0.001). It was concluded that scavenging pullets and layers were getting around 28% and 18%, respectively, of their nutrient requirements from scavenging activities, resulting in correspondingly lower supplement feed conversion ratios and feed costs. Daily gains of the pullets were not affected by scavenging or protein supplement, but egg production and mortality were lower for the confined hens.

Effect of Scavenging and Supplementation of Lysine and Methionine on the Feed Intake, Performance and Carcase Quality of Improved Dual-Purpose Growing Chickens

“…The actual proportion from scavenging may have been even higher, as the birds would have required additional energy for scavenging activities. These proportions are much lower than the values found for pullets and laying hens in similar studies carried out in northern Vietnam, which indicated that pullets and layers were probably getting about 28% and 22% of their nutrient requirements, respectively, from SFR (Minh et al, 2004). The proportion of the total diet from scavenging varies, and is influenced by season (Minh, 1999), flock density, breed type, and in particular experience, and it seems reasonable to assume that it takes time for young birds to learn to scavenge efficiently.…”

Effect of Imbrasia belina (Westwood) or Vigna subterranea (L) Verde or Tylosema esculentum (Burchell) Schreiber as protein sources in diets fed to Tswana hens on egg quality

“…The replacement of SBM with I. belina, V. subterranea and T. esculentum did not improve egg quality as indicated by lack of difference between eggs from hens fed control diet and other dietary treatment in terms of ST, SP and HU. The present results on ST falls within the mean value of 0.38±0.005 mm reported by Minh et al (2004) in the scavenging chicken supplemented with protein. Similar results were reported by Tulenu et al (2008) when layers were fed velvet bean.…”

“…However, Minh et al (2004) reported a lower SP (9.3±0.15 to 10.4±0.15%) in scavenging hens supplemented with protein in Northern Vietnam. Diets and age also had no significant influence on HU.…”

Growth and egg production of layer pullets can be affected by the method of supplying energy and protein sources

“…These results indicate that E60:P40 and EPFC pullets were able to produce eggs at a rate comparable to that of pullets fed a complete diet when they were introduced to self‐selection at 9 weeks of age, though the laying period was rather short and treatment effects may change over the full laying year. Furthermore, these results support the ideas that dietary protein is overridden at onset of production in order to achieve optimal egg production7, 31 and that early commencement of the choice feeding regime is necessary for optimal output 10…”