# Influence of Agro-Industrial By-Products Inclusion on Growth Parameters and Carcass Quality in Ovella Galega Lambs

## TL;DR

This study shows that adding 10% agro-industrial by-products to lamb diets does not harm growth or meat quality in Ovella Galega lambs.

## Contribution

The study introduces the viability of using agro-industrial by-products in the diet of an autochthonous lamb breed without compromising productivity or carcass quality.

## Key findings

- Replacing 10% of lamb feed with agro-industrial by-products had no negative impact on growth parameters.
- Carcass quality traits like weight, fatness, and conformation remained unaffected by the by-product diets.
- The use of these by-products supports sustainable practices and reduces food waste in lamb production.

## Abstract

Today, the growing food demand has intensified the generation of agri-food by-products, which are frequently inefficiently managed, posing environmental and economic issues. Brewers’ grain, grape pomace, and olive cake represent some of the most abundant residues generated by the Spanish agro-industrial sector and have revealed a high potential as alternative feed ingredients. However, there is scarce information on their use in lamb nutrition, especially in autochthonous breeds, such as the Ovella Galega. In this context, our study evaluates how replacing a 10% of the finishing concentrate with these three by-products impacts the productivity and carcass quality of these local lambs. Furthermore, considering the limited number of investigations on Galician sheep as a meat producer, this work represents a starting point to enhance its handling. Data showed that the incorporation of these brewery, winery, and olive oil by-products in the finishing diets did not negatively affect the growth parameters and carcass traits of these animals. In this sense, this alternative dietary strategy could be considered a viable and sustainable approach for the production system of these local lambs, along with a promising solution to reduce food waste and boost the circular economy, aligned with the current sustainability policies.

This study investigated the impact of including 10% of dried brewers’ grain (BG), grape pomace (GP), or olive cake (OC) in the finishing diets of thirty-two Ovella Galega lambs on their growth parameters and carcass quality. Productive parameters such as live weight, average daily gain (ADG), and subcutaneous fat depots were monitored. The following carcass traits were also evaluated: carcass weight, conformation, fatness degree, morphology, and pH. Moreover, the left-half carcasses were sectioned into the main commercial cuts. Results showed that the type of diet did not significantly affect (p > 0.05) the growth performance and carcass characteristic of the animals. All groups reported similar (p > 0.05) live weights, ADG, and pre-slaughter fat thickness. In the same manner, the lack of significant variations observed in the productive parameters was also reflected in the carcass traits, showing comparable (p > 0.05) weights, dressing percentages, conformation, fatness levels, morphometric measures, and pH among treatments. Furthermore, the commercial value of the animals was not compromised (p > 0.05) by the experimental treatments. Thus, these outcomes suggest that the employment of these agri-food by-products, at moderate levels, could represent a viable and sustainable feeding approach for these autochthonous lambs.