Ruminant Nutrition for Improved Animal Health

In early lactation, cows experience negative energy balance (NEB) caused by a rapid increase in the demand for nutrients to support milk production, which exceeds the increase in feed intake. This results in lower blood glucose and mobilization of body reserves to provide additional energy. These processes are accompanied by elevated blood concentrations of non-esterified fatty acids (NEFA) and ß-hydroxybutyrate (BHBA) and decreased calcium and phosphorus levels. Many health disorders in dairy cattle are attributed to uncontrolled lipid mobilization in response to excessive NEB in early lactation. These metabolic changes increase the risk of retained fetal membranes, ketosis, mastitis, metritis, etc.

Additionally, it is well known that fat accumulation in the liver during the transition period inhibits liver glucose production. An accumulation of triacylglycerol (TAG) in the liver decreases the rate of hepatic ureagenesis, gluconeogenesis, hormonal clearance, and responsiveness. Therefore, proper liver health is necessary to maintain optimal hepatic function during the periparturient period.

At Kemin, we know that during the transition phase, Choline supplementation in rumen-protected and intestinally available form routinely increases VLDL secretion from the liver. This increases the export of hepatic fat and results in less hepatic fat concentration and a reduced risk of fatty liver. If rumen-protected Choline is fed pre- and postpartum, it reduces the risk of clinical and subclinical metabolic disorders and overall morbidity.

Read more on our Choline supplementation solution, CholiGEM™

We know that feeding high levels of dietary crude protein, or a diet with unbalanced amino acids, can cause an elevation in the concentrations of plasma urea nitrogen and milk urea nitrogen. These elevations have been associated with poor reproductive performance in early lactation dairy cows. Below are the suggested mechanisms by which elevated urea nitrogen or an unbalanced AA diet may affect the fertility of dairy cows:

1. Ammonia or urea can affect the uterine environment and impair sperm, ova, or early embryonic development and survival.
2. Exacerbating the effects of negative energy balance in the transition period because of the cost of urea excretion and the accumulation of ammonia in the liver impairs propionate conversion to glucose.
3. Decreased plasma progesterone concentration occurs.
4. Increased secretion of PGF2α interferes with embryo development and survival in dairy cows.

Overall, poor fertility in high-producing dairy cows can be partially related to the combined effects of urea nitrogen on the uterine environment and progesterone level, as well as the worsening of negative energy balance during the postpartum period.

In a nutshell, better health and lower pregnancy losses by formulating rations-based amino acids should lead to better reproduction performance on the farm level.

Learn more on this topic from one of our customers in our blog

Calving is the most challenging phase in the life of the cow. Without adequate nutrition and management, a cow's health will deteriorate, and profit will decrease. Managing ruminant health is most often connected to treating health issues once they occur. However, we must focus more on preventing these health issues by taking care of daily nutrition. Additionally, we know that formulating diets for optimal health will prepare the cow for smoother calving and improved lactation after calving. 

In dairy ruminants, it is known that increasing the lipolysis of adipose fat stores is critical during the first stage of lactation. During this stage, fat mobilization leads to increased blood levels of non-esterified fatty acids (NEFA) which are taken up by the liver and oxidized to ketone bodies, carbon dioxide, or esterified to triglycerides. The liver normally packages the triglycerides in VLDLs and secretes them, but the ruminant liver may not adequately process sudden increases in plasma NEFA. Choline serves as a methyl donor in the synthesis of carnitine which is essential for fatty acid oxidation. 

Balancing Methionine and Lysine requirements improves the antioxidant animal capacity, health status, and immunometabolism. When the first limiting AA is inadequately supplied in MP, there will be a surplus of all other AA which will not be utilized for milk and body protein synthesis. Therefore, AA will be catabolized, primarily in the liver, to produce ammonia and then converted to urea. The excretion of excess ammonia in the form of urea is an energy-consuming process. Therefore, when rations are balanced for Lys and Met, less energy is required to excrete excess nitrogen into urea.

Consequently, the preserved energy can be directed into more productive use rather than wasted for urea excretion. This is of utmost importance in the early lactation period when cows have a negative energy balance. Sparing energy during the transition period is vital for lactating cows, which ultimately helps in minimizing the incidence of metabolic disorders.

Additionally, Met plays a major role in the synthesis of apoprotein B, an essential component needed for the synthesis and secretion of very low-density lipoprotein (VLDL) that is responsible for exporting triglycerides from the liver to peripheral tissues. Met deficiency can impair the synthesis of apoprotein B, consequently decreasing the synthesis and secretion of VLDL, resulting in the accumulation of triglycerides in the liver and the formation of ketone bodies. Apart from participation in VLDL synthesis, Met and Lys have another important role in fat metabolism. They are both required to synthesize carnitine, essential for transporting NEFA from the cytosol into the mitochondria for subsequent fatty acid oxidation. Moreover, it is well known that carnitine plays an additional important role in protecting organisms from oxidative stress, promoting substrate oxidation in brown adipose tissue, and regulating energy partitioning in the body.

Download the Amino Acids booklet for more insights

How can Amino Acid formulation mitigate heat stress? Because AA formulation improves glucose production and utilization, reduces the NEB associated with heat stress and maintains milk production, reduces oxidative stress, maintains homeostasis in immune responses, reduces intake loss, helps to create low heat increment diets, and helps to restore the intestinal barrier. RP-AA supplementation improves milk production and antioxidant capacity, reduces lymphocyte apoptosis, and enhances dry matter intake and energy-corrected milk under heat-stress periods. Besides that, AA formulation can modulate host immune and inflammatory responses and restore the intestinal barrier after injury could be used in diet during hot conditions.

Stress can be regarded as something that is applied by an external source to an animal that affects the normal physiological behavior of that animal. The intake of dry matter is decreased during stress, which directly affects the output of dairy animals. Heat stress and stress during the transition phase share the same biology and cause more losses to dairy animals among multiple stressors. It's worth mentioning the importance of supplementing chromium and Choline and balancing dietary cation-anion (DCAB) in improving dry matter intake in dairy cows during heat stress.

Apart from hypocalcemia, energy balance is also linked with dry matter intake. Negative nutrient balance is primarily a function of DMI and not milk production early postpartum. Cows have the genetic drive to produce milk at all costs. A higher correlation was found between energy balance and dry matter intake. Cows under heat stress will reduce dry matter intake (DMI) by 20 – 25%, which accounts for ~40 – 50% of the associated milk yield decline. As a result of the decreased DMI, cows under heat stress enter negative energy balance (NEBAL) regardless of their stage of lactation, which can lead to losses in body weight (BW) and body condition score (BCS). Therefore, it can be important to consider nutrition strategies that lower the NEBAL associated with heat stress and allow cows to sustain milk production.

On the other hand, transition cow faces the challenge of heat stress and transition stress. The situation of hypocalcemia in dairy cows also impacts dry matter intake. In a study, when scientists induced SCH, they found that SCH significantly (* P<0.01) reduced rumen contractions and dry matter intake compared to normocalcemic cows.

The impact of SCH and heat stress is much higher than only milk fever and certain metabolic disorders. There are short-term, mid-term, and long-term negative impacts on the profitability of a dairy herd due to SCH. Hence heat stress, hypocalcemia, and energy balance are interrelated and correlated with the cow's dry matter intake.

Learn more in our webinar on heat stress