Liver Health: A Key Driver of Reproductive and Milk Performance

Originally published in the agricultural magazine La Terre de Chez Nous.
Written by Oswal Villalobos, Agr., Ph.D., ruminant expert at Jefo.

The transition period and early lactation are particularly challenging for dairy cows because their glucose requirements for milk production, immune function, and reproduction often exceed what can be supplied by feed intake. As a result, cows mobilize large amounts of body fat, increasing the risk of ketosis and fatty liver. When the liver becomes overloaded, energy metabolism, fertility, and immune function can all be compromised – three essential pillars of overall herd performance.

The liver: a vital organ too often overlooked

The liver plays a crucial role in converting nutrients into energy, detoxifying the body, and synthesizing compounds essential for reproduction. When liver function is compromised, feed intake often declines rapidly, milk production decreases, reproductive performance suffers, and metabolic disorders become more frequent. In Canadian dairy cows, the average pregnancy rate (18%) and conception rate (40%) reflect these ongoing challenges (Denis-Robichaud et al., 2016).

Optimizing liver health through precision nutrition is therefore a key lever to improve performance and increase longevity of dairy cows.

Methionine, choline, betaine, and B vitamins: a metabolic synergy

Methionine, choline, betaine, and B-complex vitamins work synergistically to support liver and reproductive function:

• Methionine: provides methyl groups essential for protein synthesis and cellular regeneration.
• Choline: supports the export liver fat as VLDL, helping prevent fat accumulation in the liver.
• Betaine: acts as a methyl donor and osmolyte, helping protect cells against metabolic and osmotic stress.
• B vitamins (B9, B12, B6, B2): support efficient energy production, protein synthesis, and fat metabolism, thereby contributing to animal performance and overall health.

In their unprotected form, these nutrients undergo extensive ruminal degradation, which reduces their intestinal availability and overall efficacy. Microencapsulation technology enables targeted release in the intestine, ensuring optimal absorption and a sustained physiological effect. Internal studies, as well as peer-reviewed research, also show that providing these nutrients in a balanced, rumen-protected form, supports liver function, reduces the incidence of fatty liver, and improves reproductive performance.

Research-backed benefits

A meta-analysis published in the Open Journal of Animal Science demonstrated rumen-protected B vitamins and choline supplementation significantly improves liver health and reproductive performance in transition cow:

• +30% pregnancy rate at 100 days in milk (DIM)
• +13% conception rate
• -22% mastitis and -27% metritis
• -40% cases of ketosis (BHBA > 1.2 mmol/L)

Nutrigenomic analyses also revealed increased expression of key genes associated with improved oocyte quality and earlier ovulation (RGS2, INHBA, FOLR2), while SELL, TRD, IL1B, MUC5B were linked to improved embryo survival.

These results confirm that a targeted nutritional approach can influence the expression of reproduction-related genes, turning cellular health into measurable performance.

A direct impact on herd profitability and well-being

A healthy liver supports efficient energy mobilization, milk production, and fertility. Beyond performance gains, this approach also improves animal welfare and farm profitability. Based on economic estimates, a 15-20% improvement in pregnancy rate could represent an additional 230 to 310 CAD per cow in profitability, depending on production conditions (values updated to 2025).

Liver health is therefore more than metabolic issue: it is a key lever for efficient reproduction, sustained lactation, and a more resilient herd.