L-selenomethionine is a unique molecule as it has the ability, as an amino acid, to be incorporated into animal and bacterial proteins. Lysis of rumen micro-organisms in the abomasum liberates high quality microbial protein, including L-selenomethionine, which will be readily available for absorption in the small intestine, ensuring a Se reserve in ruminant tissues.
Higher availability as a condition for economic yield
Low reactivity and subsequent high availability are important high quality characteristics of hydroxy Cu, Zn and Mn. As a result, in various animal trials, both under practical and controlled conditions, hydroxy trace minerals show higher rumen fermentation, dry matter digestibility, milk production and (claw) health.
Replacing sulphates, oxides and chelates with hydroxy trace minerals has also shown improved fertility.
This has been expressed as a higher percentage of successfully inseminated cows at first service, reduced interval calving/successful insemination and lower percentage of cows needing more than three inseminations. These fertility improvements result in an important cost saving for the farmer.
Stressful periods (for example, periparturient period, heat, weaning) are plentiful during life and always correlated with an increase in oxidative stress.
To combat this stress the animal is in need of high bioavailable Se. The periparturient period in particular, presents a big challenge to ruminants as they transition from late gestation to early lactation.
The calving process and the increased metabolic activity and energy demand that marks this period, is linked to a high increase in oxidative stress. In literature, it is seen that supplementation of organic Se to Se-adequate cows during late gestation improves antioxidant function in early lactation.
This leads to effective attenuation of oxidative stress. Plasma malondialdehyde, which is a biomarker for lipid peroxidation, and reactive oxygen species (ROS) levels are lowered significantly postpartum with organic Se supplementation.
The plasma total antioxidant capacity (T-AOC) is also significantly improved. These results show that storable Se has a big positive impact during stressful periods. Positive effects for organic Se are also seen for the immune system (neutrophils).
This effect is beneficial in improving the mammary gland health, where the primary defence mechanism is the phagocytic activity of neutrophils, and lowering the somatic cell count (SCC).
Birth to weaning also presents a huge challenge for calves and stress reduction is key.
To enhance the Se status of calves during the first weeks, Se transfer from cows to their offspring via colostrum/milk is essential. When the effect of supplementation of different sources of Se on the Se concentrations in milk from dairy cattle was investigated, L-selenomethionine increased the milk Se level to the highest extent throughout the whole trial period.
To supplement feed with trace elements, it is important to choose a high quality trace mineral source to guarantee the best supply of these essential nutrients to the animal.
Hydroxy trace minerals and L-selenomethionine (Excential Smart and Excential Selenium 4000, Orffa Additives BV, The Netherlands), with no implications for rumen functioning, provide your animals with these nutrients in a safe and optimal way.
References are available from the author on request