August 7, 2019
The importance of feeding choline during the transition period to help support early lactation body fat mobilisation, milk production and cow health is becoming increasingly well recognised, AB Vista said.
However, new research is highlighting additional benefits for calf growth and immunity that have far-reaching implications.
"Choline is an essential nutrient that can be synthesised by the cow, but is always in deficit during early lactation - the demand for choline by the liver to convert body fat into available energy is just too great," said Dr. Derek McIlmoyle, AB Vista's EMEA ruminant technical director.
"As a result, supplementation with rumen-protected choline through transition has been found to not only increase both peak yield and lactation persistency, but also reduce typical early lactation health disorders."
In research carried out at the University of California-Davis, supplementation with Balchem's ReaShure rumen-protected choline (for three weeks pre- and post-calving) considerably lowered the incidence of metabolic issues (57.1% to 38.4%). This included reductions in clinical ketosis (11.3% to 4.0%), mastitis (22.5% to 14.8%) and displaced abomasums (4.5% to 2.3%).
Emerging calf benefits
In addition to this, new data is now highlighting the positive effect that choline supplementation can have on the calf. Mirroring discoveries within human nutrition research, the impact on calf growth and immunity is significant, with knock-on benefits for future lactation performance and longevity.
"We're at the very start of the research into this area of choline benefits, and we're likely to see a steady release of new data over the next few years," Dr. McIlmoyle added.
"In one of the most recent sets of trials to be published, for example, calves born to choline-supplemented cows were 13kg heavier at 12 months of age despite being born lighter - easier calving being another benefit – whilst also showing improved immune response."
Independent research results
The first part of the trial, which was carried out at the University of Florida, used 59 female Holstein calves born from dams that had either been fed a standard transition ration, or the same ration supplemented with the rumen-protected choline ReaShure. Supplementation was started three weeks pre-calving, and the result was a significant improvement in both calf growth, and calf immunity, which was based on predicted antibody (IgG) absorption from colostrum (28.1% versus 21.8%).
The results are backed up by earlier research that measured colostrum quality. Cows supplemented with ReaShure rumen-protected choline pre-calving produced a similar volume of colostrum to those not receiving choline (9.9 vs. 8.5 kg/day), but colostrum quality - in terms of IgG concentration - was significantly greater (figure 2).
Improved immune response
The impact of this potential improvement in calf immune status was tested in a second trial using the 38 Holstein bull calves born to the choline-supplemented and unsupplemented cows. At around 19–24 days of age, each was exposed to lipopolysaccharide (LPS), a compound found in the cell walls of pathogenic bacteria like E.coli and known to trigger internal immune response.
"The trial found that calves born to the choline-supplemented cows had increased concentrations of key white blood cells," Dr. McIlmoyle explained. "It's a response you'd expect from a more mature immune system with a greater capacity to respond to disease threats.
"The calves also had a higher glucose status and lower levels of blood β-hydroxybutyrate (BHB) and fatty acids, indicating improved metabolism and fewer nutrients going toward fighting disease and inflammation. The overall result was an even greater difference in growth rate after the LPS was administered."
Human research studies have also been highlighting the important role choline plays. It's both an essential compound in various metabolic processes and a key component of the neurotransmitter acetylcholine, which is an important messenger compound in the central nervous system.
Furthermore, studies have found that large amounts of choline are delivered to the foetus across the placenta, with choline concentration in amniotic fluid ten times that found in maternal blood.
"There are now clear indications that choline-supplementation during the transition period not only improves cow health and performance, but also that of the calf," Dr. McIlmoyle concluded. "Faster growing, more robust calves will also be larger at calving – or reach target weight sooner – with knock-on effects for subsequent lactation performance and longevity in the herd.
"Given the immense stress young calves are under, due to both environmental pressures and group housing, it should be no surprise that choline-derived improvements in immune status produce better calf performance. It means that choline-supplementation has multi-generational effects we've not previously considered, with important implications for overall herd profitability, and it's definitely an area of research worth following closely."
- AB Vista