In today’s world, dairy leaders are facing difficult challenges. Industry consolidation along with changes in consumer perception of dairy products makes the dairy industry very competitive. Understanding and responding to the main trends is paramount to the dairy operation’s success.

The DKC’s multidisciplinary team researches and brings insights and strategies that help dairy leaders to drive better business decisions. The DKC’s insights provide valuable knowledge in critical business areas such as nutrition and feeding, reproduction, housing, replacement, and management practices.

Cows

Effects of vitamin E supplementation on milk production and reproductive performance

Maria Villagrasa & Fernando Diaz

Vitamin E is an essential nutrient for cows, but the effects of its supplementation are often controversial in the scientific literature. The goal of a recent meta-analysis published in Journal of Dairy Science was to evaluate the effects of vitamin E supplementation and serum vitamin E levels on productive and reproductive variables of dairy cows in transition.

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Calf

Omega-3 fatty acids supplementation improves performance and immunity of dairy calves

Alvaro Garcia

Growing healthy dairy calves is critical for the profitability and sustainability of dairy operations. Their first weeks of life will define if they are going to turn into highly productive future dairy replacements. Supplementing calf with energy-supplying ingredients such as oils rich in poly-unsaturated fatty acids (PUFA) affect weight gains, immunity, antioxidant status, and metabolism.

Research has shown that the inclusion of PUFAs helps in the treatment of diarrhea and other inflammatory conditions early in life. This occurs by changing the ratio of PUFAs in the phospholipid fraction of the immune cells which alters the immune function. Of these PUFAs, linoleic and α-linoleic acid seem to have the greatest impact against the challenge posed by microbiological antigens.

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Butter block

Rumen-protected folic acid and betaine supplementation improves milk component yield

Alvaro Garcia

Diet formulation for lactating dairy cows requires a thorough understanding of ruminant biology. Their unique digestive system makes them susceptible to disfunctions of the pre-stomachs when departing from their requirements. Successful nutritionist understand that they need to feed two interdependent systems, the host itself (the cow), and the microorganisms populating the rumen.

Supplying the reticulum and rumen with energy, nitrogen/protein, minerals and even vitamins, maximizes the growth of the microbial population and allows the fine-tuning of this symbiotic relationship. Different microbial groups within this population have specific needs and are specialized in their ability to degrade different substrates.

Folic acid and betaine activity on rumen microbiome and mammary gland

Recent studies for example have indicated that folic acid (FA) addition to the diet stimulated DNA synthesis in dairy cows and upregulated the gene expression related to protein synthesis in the mammary gland. Folic acid is reduced to tetrahydrofolate which is essential for the growth of Ruminococcus (R.) flavefaciens.

Dietary rumen-protected folic acid addition has increased cellulolytic bacteria population and the activity of its enzymes, α-amylase and protease. It has also had a positive effect on milk and milk protein yields. Betaine, the trimethyl derivative of glycine, arises from choline oxidation and is used in osmoregulation and transmethylation reactions.

Betaine donates a methyl group to regenerate methionine from homocysteine and is then converted to dimethylglycine. The methyl groups of the latter are split-off through oxidation and transferred to tetrahydrofolate to generate 5,10-methylene- tetrahydrofolate. Dietary betaine supplementation has been shown to increase intestinal microbes, digestive enzyme activities and nutrient digestibility in single-stomached animals and helped maintain the structure and activity of the mammary gland cells in dairy cows.

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Butyrate supplementation improves production of lactating dairy cows

Alvaro Garcia

Adequate rumen papillae growth is indispensable to maximize the absorption of volatile fatty acids (VFA) in ruminants. In wild African ruminants for example, there is a change in papillae growth and epithelial intestinal growth between the dry and rainy seasons which results from the quality and abundance of the forage available.

Something similar happens when dry cows are fed low quality, highly fibrous forages that do not stimulate the production of VFA that are critical for papillae development. Similarly, in the pre-weaned ruminant, early development of these epithelial structures allows them to accelerate the transition to a ruminant with a functional rumen, thus reducing feed costs.

Recent research has demonstrated that high dietary fiber (NDF) to starch ratios negatively affect the expression of the gene regulating growth of papillae. The right ratio of volatile fatty acids in the diet then determines how much of those volatile fatty acids will be absorbed, and how much energy the cow will obtain from its feed!

Metabolic pathway of the butyrate synthesized in the rumen of lactating cows

Lipogenesis is the result of metabolic steps to synthesize of fatty acids and then triglycerides. The major locations in the body varies somewhat but it generally takes place in the intestinal mucosal cells, the liver, the adipose tissue and the mammary gland in lactating animals.

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Milk yield and components in dairy cows fed exogenous enzymes

Alvaro Garcia

Adding fiber-degrading enzymes to the diet of dairy cows has been explored for quite some time. These exogenous enzymes allow for a greater digestibility of the roughage which results in more nutrients available for production. Recent publications have shown that the range of increased milk production has been between 0.20 and 3.6 kg/day however, the results have been inconsistent.

The main reason for this variability is that there are multiple factors that influence the response. Examples are differences in enzymatic activity, dosage, days in milk, time of delivery, ruminal microbial population, enzyme stability and specificity of the enzyme to the type of fiber in the diet.

As could be expected, the ration composition and particularly the forage/concentrate ratio, bear also significance on the degree of response to these enzymes. Diets that consist of a larger proportion of forage (50% and above) will obviously elicit a greater response provided the type of fiber and the enzyme added have an acceptable degree of compatibility. It is thus critical to test which are those conditions that optimize the fiber-degrading effects of these enzymes.

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Several cows eating hay in a dairy farm

Evaluation of supplemental carnitine in dairy cows during the pre- and postpartum period

Alvaro Garcia

The transition period is the most challenging time for a dairy cow. Right after calving cows start producing colostrum first and then milk in large amounts, depending on their genetic make-up. At this point in time however, they are in recovery mode from calving, and a combination of general discomfort/pain and hormonal changes results in a significant reduction of feed intake.

This mismatch between nutrient requirements for production and nutrient uptake through feed intake, results in imbalances, with the supply of energy being the more striking. One example of hormonal changes is the decreased production of insulin that leads to decreased glucose utilization by insulin-sensitive organs, which is essential for milk production. Concomitantly, body fat reserves are mobilized to supply additional energy which increases the non-esterified fatty acids (NEFAs) blood concentration.

The abundance of circulating NEFAs leads to increased availability of the product from their degradation, acetyl-CoA, which may exceed the capacity of its incorporation into the carboxylic acid cycle. As a result, end-products normally utilized in ketogenesis will build-up, such as acetone, acetoacetic acid, and beta-hydroxybutyric acid (BHBA).

L-carnitine helps to handle excessive non-esterified fatty acids

The increased circulation of NEFAs leads to triacyl glyceride synthesis later deposited in the liver. To handle the excessive NEFA availability L-carnitine is needed which is essential to transfer fatty acids into the mitochondria for their oxidation. L-carnitine is synthesized endogenously, and it is essential in the initial steps of the ß-oxidation of free fatty acids. When in short supply, all the events described above can happen leading to frequent metabolic problems in transition cows such as fatty liver and/or ketosis.

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Swiss Brown cow, portrait

Betaine allows dairy cows to better cope with heat stress

Alvaro Garcia

Alleviating heat stress is critical to sustain milk production under warm weather conditions. Maintaining optimum nutrient balance and providing highly palatable, digestible feeds and ample supplies of fresh, clean water, along with shade and ventilation, will go far towards keeping cows comfortable and milk production up.

Heat stress from high environmental temperatures can be compounded by mistakes in managing and feeding cows. Water is the first concern during periods of high temperatures. Water physical properties (heat conductivity and latent heat of vaporization) help transfer heat from the body to the environment. Dry matter intake of lactating cattle is affected when ambient temperatures are outside of the cow’s “comfort zone” (5 to 25 ºC). When ambient temperatures increase beyond 25 ºC, the cow typically reduces intake and as temperatures continue to rise it can finally go off-feed.

Less ingestion of dry matter in hot weather

Dry matter intake can decrease by around 150 g of feed for each degree above 25 ºC. This is just a physiological mechanism by which the cow attempts to reduce the heat increment that results from feed fermentation and metabolism. Heat is produced as a result of microbial fermentation in the pre-stomachs. Low quality, stemmy forages generate more heat of fermentation, contributing to the animal’s total heat load.

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Silage balls in a foggy landscape

Baling grass silage with tannins reduces environmental nitrogen load

Alvaro Garcia

The fate of nitrogen (N) ingested by dairy cows is approximately 34% in milk protein synthesis, 34% eliminated in the urine, 27% in the feces, with only 5% retained to be used in other body processes. These figures show that close to 60% of the nitrogen intake ends up being a source of environmental N load.

Not only is N tied-up in urine and feces but it also results in gaseous N losses through nitrous oxide which is also a greenhouse gas nearly 300-fold more potent than carbon dioxide. Ammonia gas production is also of concern since it is hazardous both for humans and livestock. As a result, improving N partitioning will have an effect in the environmental load associated with livestock production as well as air quality.

What is the effect of adding tannins to the silage on cow’s nitrogen metabolism?

Oak tannins applied to forage before baling it for silage improve protein partitioning in the cow lessening the environmental N load. Research has shown that adding tannins to forages before ensiling can lead to a reduction in ammonia production. Tannins have also been used to protect fermentable protein from rumen degradation which is later digested once it is freed from the tannin complex once it reaches the more acidic pH of the abomasum. This latter effect results in less plasma urea N, less milk urea N, and reduced N excretion in the urine.

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Holstein cow feeding grass

Feeding yeast improves performance of dairy cows under heat stress

Alvaro Garcia

Hot summer temperatures are a highly limiting factor for milk production of dairy cows. To maintain body temperature, cows reduce intake, which decreases the heat increment that results from rumen fermentation. In order to improve milk production under these conditions it is necessary to restore intake, and/or improve nutrient digestibility. Since forage fiber requires more time for its degradation in the rumen, it produces more heat of fermentation than concentrates.

Less fiber in the diet however, results in less chewing, reduced saliva production, more grain fermentation, and ultimately a more acidic rumen pH. These changes shift the pattern of fermentation from predominantly acetate to propionate→lactate, risking the appearance of sub-clinical or clinical rumen acidosis. Past research has demonstrated that feeding live yeasts or yeast cultures increases milk production of cows under heat stress.

Could Saccharomyces cerevisiae help cows under heat stress?

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Three cows eating total mixed ration (TMR)

Organic acid-based products can improve milk production

Alvaro Garcia

Mixers and total mixed rations (TMRs) are the feed delivery method of choice in modern dairy operations in confinement. Their greatest advantage is that they allow for more even delivery of nutrients, and a steadier rumen fermentation. In fact, it is this technology that has allowed cows to fully express their genetic potential for production, encouraging greater intakes, and higher milk yields.

Cow response however is associated to the quality of the feedstuffs included in the TMR. Individual feeds can suffer deterioration when exposed to less than ideal conditions (e.g. air, heat, moisture, etc.) that lead to proliferation of microorganisms, toxins, that reduce feed quality. Molds and yeasts for example have been known to consume organic matter in silages, reducing their feeding value and/or producing toxins detrimental to animal performance and health.

Organic acids inhibit the proliferation of bacteria and fungi

Several additives have been researched that inhibit the proliferation of microorganisms. Organic acids for example inhibit the proliferation of bacteria and fungi helping maintain the nutritive value of the feed and reduce potential mycotoxin toxicity. Their mechanism of action has been proposed to be by allowing hydrogen to enter the microorganisms cell membrane, thus reducing the pH in the cell cytoplasm. Propionic acid for example, has been demonstrated to reduce pH and temperature when added to the TMR.

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