I don't think you phrased the question correctly. Organic livestock production does not just mean eliminating the use of antibiotics. Therefore, in my opinion, it would be correct to clarify your question as to whether you mean the effect of organic livestock production on the scale and yield or whether you are interested in the effect of not using antibiotics in livestock farming on scale and yield.
It is difficult to predict the future with certainty, but organic livestock production has been growing in recent years and has the potential to become a major strategy in the meat and dairy sector. This growth can be attributed to increasing consumer demand for organic and sustainably produced products, as well as the recognition of the health benefits of organic food.
However, organic livestock production tends to be more resource-intensive, including higher costs for feed and land, which can make it more challenging to compete with conventional production methods on price. Additionally, organic production standards often limit the use of certain inputs, such as antibiotics, which can make it more difficult to maintain animal health and productivity.
Therefore, it is likely that organic livestock production will continue to occupy a niche within the meat and dairy sector, but it may also expand as consumers become increasingly interested in the health and environmental benefits of organic food. The growth of organic livestock production will also depend on the ability of producers to meet the demand for organic products, as well as on the regulatory framework and the economic and market conditions in different regions.
Given the growth in the world population I cant see this as a viable large scale production option. Some of the practices required by organic production can likely be adopted, but overall efficiency of production and health status of livestock is really difficult to maintain at a sufficient level to produce the food requirements of the planet in organic systems.