The use of feed protein in dairy farming, from feed to milk, has improved significantly in recent decades. This improvement resulted in higher nitrogen utilization in dairy cows and lower ammonia emissions per kg of milk. This project aims to develop innovative feeding strategies for rumen resistant methionine, in order to achieve a resilient healthy cow, in combination with a sustainable use of proteins.
Reducing the protein content in dairy cow rations requires an optimal ratio between rumen degradable protein and intestinal protein and an increasing awareness of the importance of available rumen resistant amino acids.
In feed for pigs and poultry it is quite common to add essential amino acids. Due to the more complicated digestive tract in ruminants, amino acids must be 'rumen protected' for optimal utilization in the animal. Rumen-protected methionine (RPM) is a well-known synthetic amino acid product for dairy cows. In low-protein diets, the addition of amino acids offers opportunities for customized nutrition in combination with a further reduction of ammonia emissions. A better supply of methionine in the small intestine not only benefits the performance and environmental aspects of the dairy cow, but also the health condition. The hypothesis: increasing the methionine supply in the small intestine through the addition of feed during the pre- and postpartum period benefits the health and metabolism of the animals during the subsequent lactation. If application of these products does indeed improve health conditions, society will see it as a sustainable solution for future livestock systems.
Genetic selection for higher milk yield has significantly manipulated the intermediate metabolism of today's 'modern dairy cow'. With success, because this is reflected in the production of larger quantities of milk over a longer period of time (Opsomer, 2015). It is therefore not surprising that the transition period and its associated biology and management remain central to dairy nutrition and physiological research. Despite the considerable amount of research into the nutrition and physiology of transition cows, the transition period continues to demand a lot of attention on many dairy farms. Metabolic disorders are still prevalent and have a significant economic impact on commercial dairy farms (Overton and Waldron, 2004)
Specific amino acids
Scientific research (Li et al., 2016) reveals an important role of specific amino acids, such as methionine, targeting gene expression of crucial mechanisms in the transitional period. High-risk cows, such as calving cows with a generous condition, clearly benefit from this specific amino acid supplement. Recent studies in the US have shown that supplementing the transitional diet of dairy cows with RPM is an effective method to reduce animal inflammation and improve liver and neutrophil function, ultimately improving postpartum performance of dairy cows through a better immune system ( Batistel et al., 2017, 2018). However, interactions of these mechanisms are not known in Northwest European diets consisting of grass and grass silage.
In monogastric animals (one stomach), gut health and nutrition has been studied for decades. In ruminants, rumen fermentation and nutritional aspects were important research questions, prompted by the complicated digestive tract. The current proposal has been carefully designed to integrate performance (production/nutritional utilisation), clinical and metabolic aspects. The aim is to gain a better understanding of the beneficial effects of balancing methionine in the diet on the performance and health of dairy cattle. It goes without saying that both aspects interact. From this point of view, nutrition should be aimed at (intestinal) health and, in the second place, at covering the nutritional requirement.
For the dairy chain, integration of health and performance in tailored nutrition is indispensable for a sustainable dairy sector. Feeding less protein requires an advanced feeding model. Knowledge of metabolic and immune status as a result of amino acid supplementation can help improve benefits, as well as social acceptance.
Two groups of 16 cows each are selected, one group as a control, while the other groups receive RPM in the feed. At the start of the dry period, the cows are housed in the 'Transition barn' on Dairy Campus. Three weeks before calving, the cows go to the 'Feeding Barn' with daily feed intake registration by the RIC system. After calving, the trial continues for 45 days.