Abstract
Information on feather and skin growth is important for the development of mathematical optimisation nutritional models for ostriches. Ostriches (n = 65) were subjected to a four-stage formulated growth diet programme (pre-starter, starter, grower and finisher), with declining protein and energy content. Nine birds were weighed, stunned, exsanguinated, defeathered, skinned and eviscerated at 1, 54, 84, 104, 115, 132 and 287 days of age. Feathers from four pre-selected locations on the body were harvested and weighed. The wet skin weight, wet unstretched skin size and wet unstretched crown size were measured at each slaughter stage. The live weight, feather and skin yields of the birds increased with age at slaughter, as did feather shaft diameter. Prediction models were developed to estimate the yield of the skin in terms of live weight and of empty body protein weight to aid in diet formulation. The allometry of feather growth was determined from total feather weight, as the maturation rates of the feathers differ from that of the ostrich body. Results from this study will aid in setting up a mathematical optimisation nutritional model for ostriches.
Highlights
A model can be defined as the simulation of a system that enables predictions that are as close to reality as possible
This study was based on the total feather weight of the birds at each slaughter age and no adjustments were made for feathers lost during general animal husbandry practices
The feather growth was defined in terms of the total feather weight rather than from live weight or empty body protein weight (EBPW)
Summary
A model can be defined as the simulation of a system that enables predictions that are as close to reality as possible. Emmans (1989, 1995) and Ferguson (2006) stated that a bird will attempt to grow at its absolute genetic potential. Growth of the empty body (without gut fill) can be seen as the weight accumulation of protein, ash, water and lipid, while biological tissue growth follows a sigmoidal pattern (Huxley 1932; McDonald et al 2002). These tissues and components are allometrically related. Relating all components to a standard factor like the featherless empty body protein weight (EBPW) will provide a way to compare and predict body component growth (Emmans 1989; Ferguson 2006)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have