Currently, Dairy Campus is investigating whether sorghum can be used as roughage on a dairy farm, in addition to grass and maize. In this way, the rotation with maize can be expanded and the disadvantages of continuous maize cultivation can be avoided. To determine the effects of sorghum on feed intake, milk yield, milk composition, feed efficiency and methane formation in the rumen released via the respiratory air, a trial with 16 cows is being conducted in the feeding shed at the innovation center in Leeuwarden.
In this project, the potential of sorghum in dairy farming is investigated with the aim of increasing crop rotation in dairy farming. Sorghum is a new crop for the Netherlands (and Belgium) that resembles maize in terms of growth habit, cultivation and composition.
The trial was recently started with a pre-period of 2 weeks in which the cows get used to the group, the feeding system and the ration. During this period all animals already receive a share of sorghum silage in the ration (25% of the total roughage amount).
After the pre-period, the study will continue for another 12 weeks, divided into 4 periods of 3 weeks each. The animals are divided into four groups of 4 animals. Each group receives one of the test rations for 3 weeks. The trial ration changes after every 3-week period. At the end of the trial, all animals received all rations. At the start of the trial, the cows are in lactation between 60 and 120 days.
Three levels of sorghum silage are used, respectively. 16.7%, 33.3% and 50% of the roughage dry matter, plus a control ration without sorghum. In all rations 50% of the roughage consists of grass silage and sorghum replaces (a part of) the maize silage. In addition, the animals also receive concentrates in the milking parlor, the concentrates box and the Greenfeed. Here the individual methane emissions in rumen gases are measured.
The individual feed intake, milk yield, milk composition and body weight of the participating cows are measured.
Step to practical implementation
There is a need for knowledge about the effects of sorghum in the diet on feed intake, milk yield, milk composition and feed efficiency of dairy cattle (Kasper, 2017). This knowledge is necessary to be able to take the step towards practical implementation. In addition, there is a lack of knowledge and quantitative information about enteric methane formation (methane formation in the rumen that is released via the breathing air) in dairy farming when sorghum is included in the diet. Because the methane emissions from Dutch livestock farming must be reduced by 1.0 megaton of CO2 by 2030, information about this is crucial.
The first results will be available in autumn 2021.
The cultivation and feed research is part of the Public Private Partnership Sorghum (PPS 2019-2022), funded by ZuivelNL and the Ministry of Agriculture, Nature and Food Quality, in which the perspectives of sorghum are explored and research is conducted into cultivation and nutritional aspects for dairy cattle. Other companies involved are LTO-Nederland, DSVzaad Nederland BV, Maatschap de Milliano-Meijer and CZAV. The research is being conducted by the knowledge institutes Louis Bolk Institute and Wageningen Livestock Research.