Adequate ration balancing is a crucial component of a dairy farm budget. Undetected nutrient deficiencies or excesses can have different and variable effects on cows’ performance and health. Nowadays more feed ingredients are available to be included in dairy diets.

With feed comprising the largest operating expense, nutrient composition of feed ingredients and feeding strategies are the key profit drivers in modern dairy farms. The DKC’s Feed Library publishes recent research on the main feeds included in dairy cattle diets.

Cereals

Feeding barley forages in high-concentrate diets for lactating cows

Alvaro Garcia

Growing forages in arid regions of the world is one of the biggest constraints to profitable intensive dairy production. Under these conditions dairy production systems rely heavily on forages that require less water together with mostly imported grain. In addition, dairy rations tend to include higher concentrate to forage ratios since it makes more economic sense to transport energy dense feeds (grain) than roughage.

In Israel for example, total mixed rations (TMR) fed to dairy cows contain 33–36% roughage, a bare minimum needed to supply 18–19 % neutral detergent fiber (NDF) needed in order to minimize the risk of acidosis. As a result, winter forages such as wheat (Triticum spp.) supply nearly 70% of the annual forage, complemented with corn silage during the summer irrigated with recycled water.

Wheat and barley forages

Nearly 40,000 Ha of wheat both for silage and hay are grown yearly as the main winter forage in Israel, followed by barley (Hordeum vulgare L.) with only 2,500 Ha for silage and 3,500 Ha as grain for feeding. Wheat is an important crop in this system since it provides flexibility, switching from grain to forage and vice versa depending on environmental conditions.

Barley’s yield, quality, and nutritive value are less known at the present time particularly of those cultivars grown for silage in the same fields and under similar conditions as wheat. One of the advantages of barley in this semi-arid environment is that it apparently uses water more efficiently, it has early vigor, and matures faster compared to wheat resulting in higher yields per Ha.

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Factory

Adding molasses to dry cow diets improves intake and health of dairy cows

Alvaro Garcia

The transition period of dairy cows is characterized by changes in behavior, hormonal patterns, and increased metabolic and nutrient demands. Cows in late gestation (2-3 weeks to calving) undergo changes in metabolism and a mismatch between dry matter intake/nutrient uptake and their requirements, which prompts the mobilization of body stores, mainly fat from adipose tissue and glycogen from the liver.

These changes also predispose to metabolic disorders such as ketosis, acidosis, and displaced abomasum. Research has shown that feeding lower dietary energy including more fiber in the diet, promotes intake after calving, and results in less body fat mobilization. It has also been suggested that moderate energy intake pre-calving may positively impact cows’ fertility.

Which is the most suitable diet for dry cows?

Today’s suggestions are to feed dry cows low energy diets [1.30 to 1.39 Mcal of net energy for lactation (NEL)/kg of dry matter (DM)] during the entire dry period. One limitation is that high straw diets result in rumen filling at a stage of the pregnancy where the fetus is already occupying more space, and that they may also increase the risk of feed sorting.

Recent research however has also suggested that high fiber:starch ratios inhibit the expression of the genes regulating rumen papillae growth. The challenge is to feed fibrous roughages while promoting the development of an adequate rumen papillae surface needed to absorb the sudden increase in volatile fatty-acids resulting from the highly digestible feeds available in early lactation.

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Tractor working with forage

Optimizing nitrogen fertilization in timothy grass

Alvaro Garcia

Timothy grass (Phleum pratense) is a perennial grass originally from northern Europe. It is a tall grass species which can grow up to 1.5 m at the reproductive stage. It performs well in heavy, poor sandy soils, and is resistant to cold weather and dry conditions. As other grass species it requires adequate soil nitrogen for optimal growth.

Timothy and other cool season grasses generally respond well to nitrogen fertilization, with 20 to 25 kg of herbage dry matter produced yearly per kg of nitrogen/hectare. Response is related to the original nitrogen availability in the soil, with a greater response in more deficient areas.

Nitrogen fertilization

The timeline of the nitrogen application also affects the quality of the sward. When applied later into the growing season it leads to more vegetative growth compared to tall, more hardened stems earlier in the season. This is an important consideration depending on the region since vegetative growth is desirable for quality, although it may also lead to more winter damage.

It is important then to optimize fertilization rates such that they not only increase herbage dry matter production, but also result in forage that withstands the cold season while still maintains adequate quality. As with other grasses, nitrogen fertilization increases not only the crude protein content of the plant but also its concentration in nitrates, which could be potentially toxic to ruminants.

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Sunflower

Crushed sunflower seeds modify milk fatty acid profile in dairy cows

Alvaro Garcia

It is currently accepted that acetate produced from fiber fermentation in the rumen, supplies nearly 40% of the building blocks for de-novo milk fatty acid synthesis in the mammary gland. Of the remaining milk fat, 10 % comes from circulating fatty acids mobilized from fat stores, and 50% coming arises from the diet.

Dietary phospholipids have health-promoting effects in humans such as inhibition of colorectal cancer, reduce the prevalence of gastric ulcers, and decrease the absorption of cholesterol. The latter likely results from the physical intestinal interaction between phospholipids and cholesterol, decreasing the absorption of both.

The fatty acid (FA) composition of phospholipids influences this bonding since their long-chain saturated FA interact more strongly with cholesterol than the unsaturated form. These phospholipids are in the milk fat globule membrane and dairy products rich in this membrane (i.e. buttermilk) are good sources of these phospholipids.

Dairy cows’ milk fat has 0.2 to 1% phospholipids with sphingomyelin constituting approximately 20% of them. Since sphingomyelin has a high proportion of long-chain saturated FA, this allows for a better interaction with cholesterol. These strong sphingomyelin-cholesterol bonding is essential for cell function. They are also present in the milk fat globule membrane, suggesting that this complex may play a role in the hydrolysis and absorption of milk fat by the calf.

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Vineyards

Feeding grape pomace reduces methane emissions from lactating dairy cows

Alvaro Garcia

The wine industry leaves behind an interesting coproduct which is called grape pomace. It consists of the solids that remain of grapes after they are pressed to remove its juice, and it contains the skins, pulp, seeds, and stems. In the alcohol beverage industry, water is added and allowed to ferment to produce “grappa”, a well-known alcoholic beverage originating in Italy.

Grape pomace is also used nowadays as a feedstuff for cattle, fertilizer, or to extract from its bioactive compounds such as polyphenols. Nearly nine million tons are produced annually around the world, with well-known wine regions being the main source of it. Its availability is not to be discounted since they constitute one fourth of the grape weight before its fermented into wine.

The dairy industry is well known for producing highly valued dairy products however it is also blamed for increasing the carbon footprint of agriculture. Industry coproducts such as grape pomace which are relatively inexpensive and need to be disposed-off in an environmentally friendly way are often used as feedstuffs in dairy cow diets. In addition, they are also considered not contributing significant volumes of greenhouse gases, since any emitted are mostly assigned to the primary product, in this case the alcohol beverages.

Grape pomace is rich in condensed tannins which have been shown to reduce methane production when fed to ruminants. In addition, these coproducts reduced in milk fat with higher proportions of polyunsaturated fatty acids which are beneficial to human health. In countries with grass-fed dairy systems and a strong wine industry, such as Australia, this coproduct is used to stretch the forage supply and not overgraze pastures during the dry months of the year.

In the US and particularly in the wine region of the west coast, the use of grape pomace has been also a tradition, mostly to reduce feed costs. There is not much information though on its nutritional value and its variability depending on the types of grapes used to make wine. As a result, there is also not enough research performed on its effect on dairy cow milk production. There’s not much research on its relatively high concentration of polyphenols and their impact on methane production emissions.

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Broccoli

Conservation of artichoke and broccoli coproducts in baled silages

Alvaro Garcia

The artichoke (Cynara cardunculus var. scolymus) consists of a variety of a species of thistles cultivated as a food. The edible portion of the plant consists of the flower buds before the flowers bloom. Once the buds bloom, the structure changes into a coarse and barely edible form. Artichokes are cultivated in several parts of the world. In Europe they contribute to the agricultural economy of the Mediterranean region, accounting to nearly 60% of the world production.

Broccoli is an edible green plant of the cabbage family (family Brassicaceae, genus Brassica) with a large edible flowering head. Broccoli is a cultivar of the species Brassica oleracea with large flower heads usually dark green in color, surrounded by leaves and arranged in a tree-like structure branching out from a thick light green stack. It resembles cauliflower which is a different cultivar group of the same Brassica species. It is native to the Mediterranean where more than 40% is produced together with Southeast Asian regions.

Use of artichoke and broccoli coproducts to feed livestock

Once artichoke flower-heads are harvested (20% of the biomass) for human consumption, what’s left in the field are leaves, stems and some inflorescences (80% of the biomass). This byproduct has been used to feed livestock in Europe, Asia, and America.

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Seaweeds

Seaweeds in ruminant nutrition

Alvaro Garcia

It is estimated that by 2050 the planet will reach more than 9 billion people, 34 percent more than nowadays. At the same time, a higher standard of living attained by larger segments of the population, has increased the demand for animal products. To be able to feed this population, food production must increase by 70 percent not only from traditional sources but also by exploring new alternatives.

This will imply an increase on the total biomass fed to animals precisely at a time when climate variability and water shortages challenge its production in several parts of the world. One alternative that is currently being evaluated is the use of marine algae or seaweeds as a source of feed for both livestock and humans.

Its main advantage is the fact of being produced in a self-sustaining environment, without increasing the use of land base, and that does not require incorporation of resources (including freshwater!).

Groups of seaweeds

There are basically three groups of seaweeds: Phaeophyta (brown), Rhodophyta (red) or Chlorophyta (green). They have variable composition both between species, and within a species depending on the stages at which it is harvested as well as the growing conditions. There are very limited studies that report the nutritive value of seaweeds as a feedstuff for cattle.

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Pear millet field

Feeding BMR pearl millet silage to mid-lactation cows

Alvaro Garcia

Corn silage constitutes the main forage base in the predominant US dairy production systems. The reasons have been the highly beneficial growing conditions, combined with the energy density contributed to dairy cow diets. Growing corn, however, also demands the right environmental conditions. As a result, some dairy producers also grow alternative forages to use when corn yields are lower than expected particularly in warmer and drier regions of the country.

Aside from sorghum silage, one other alternative that has been explored is pearl millet (Pennisetum glaucum). Because of its origin (Africa), pearl millet is adapted to grow in drier areas of the world, thriving in low fertility soils, and warmer temperatures. It is thus a very good forage “insurance” for warmer areas of the US where environmental conditions may challenge the growth of corn for silage.

Main characteristics of pearl millet as a crop

Pearl millet is a summer crop that adapts well to double cropping and rotations. Other advantages are that its long root system allows the plant to reach deep nutrients in poor sandy soils. It has also fair resistance to pests and does not have the problem of prussic acid toxicity in cattle when its frost stricken. It is recommended to harvest more than once during the season in order to achieve even greater yields than forage sorghum.

There are newer improved varieties of pearl millet that can even yield similar forage tonnage compared to sorghum with just one cut. These new varieties include the brown mid-rib trait (BMR) resulting in higher digestibility when compared to conventional pearl millet varieties. Past research has reported the same production in dairy cows replacing 10% of the corn silage in the diet with pearl millet silage.

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Harvesting corn

Feeding corn grain to lactating cows, steam-flaked or ground corn?

Alvaro Garcia

Modern improved dairy cow genetics require energy dense rations in order to fulfill their requirements. As a result, cows in farms with high milk production oftentimes receive diets where grain constitutes no less than 60% of the formulation. Similarly, there are parts of the world where forages have become scarce and/or very expensive since they must be hauled long distances or even imported from overseas.

Under these scenarios dairy cows are challenged with grain concentrations oftentimes borderline with digestive upsets, particularly sub-clinical acidosis and in extreme cases clinical acidosis and even displaced abomasum.

Today’s corn varieties have been improved compared to those in the past and contain slightly above 20% more starch or close to 74-75%. In the corn kernel starch is in the endosperm encased in starch granules embedded in a hydrophobic prolamin-rich protein matrix, which protects it from enzymatic degradation. In order to increase the utilization of starch this matrix must be disrupted, usually by physical methods.

How to improve corn digestibility in dairy cows

These methods vary in their effectiveness depending on the type of grain and the different process, affecting in consequence the productive response of the cows. One of these methods, the reduction in particle size, has long been recognized as an effective method to increase starch utilization by livestock. Research has reported that reducing the particle size from 4,000 to 500 μm increased total-tract starch digestibility from 77.7 to 93.3%.

The larger the particle the greater the resistance of this protein matrix to water infiltration and the accessibility of starch-degrading enzymes both from the microorganisms in the rumen and the cow enzymes in the small intestine. However, the particle size excessively can greatly increase starch availability and result in the digestive upsets mentioned above, particularly acidosis.

Aside from the particle size reduction, one other method is steam flaking. Moisture and heat applied during this process disrupts the protein matrix that protect the starch and allows for easier enzyme penetration.

Steam flaking corn is frequently used in the US to improve starch digestibility both for dairy and beef cattle. As a result, diets with steam-flaked corn improve weight gains in feedlot cattle, and milk yield, milk protein yield, fat-corrected-milk (FCM) and solid-non-fat (SNF) in dairy cattle.

Results have also shown that cow performance fed diets with steam-flaked versus fine-ground corn can be similar and result in more ruminal VFA, greater total tract starch digestibility, and ultimately increased milk production. In addition, it has been speculated that cows receiving diets with these processed grains, would select longer fibrous particles to increase saliva production through chewing, and thus buffer the reduction in rumen pH.

A recent study (Ahmadi et al. 2020) evaluated the effects of diets containing steam flaked corn (SFC) or ground corn (GC) varying in particle size (fine = FGC, medium = MGC or coarse = CGC) on performance, ruminal characteristics, nutrient digestibility, and sorting index of high producing dairy cows fed high-concentrate diets.

Comparing ground corn with steam flake corn

Multiparous Holstein cows with 101 ± 10 days in milk (DIM), body weight (BW) of 607 ± 62 kg, milk yield of 46.6 ± 3.5 kg/day were used in a double 4 × 4 Latin square design. There were 21-day periods consisting of 13 days for adaptation and 8 d for sampling and data collection. Cows within each square were assigned to four dietary treatments as follows:

  1. FGC, TMR containing finely ground corn = 0.73 ± 0.2 mm.
  2. MGC, TMR containing medium ground corn (0.84 ± 0.28 mm);
  3. CGC, TMR containing coarse ground corn (1.08 ± 0.68 mm);
  4. SFC, TMR containing SFC (density of 400 g/L).

Cows were fed a TMR with a forage: concentrate ratio of 36:64 on a DM basis, with corn silage and chopped alfalfa hay as the forage components. Experimental diets were formulated using the Cornell Net Carbohydrate and Protein System to meet the energy and protein requirements of cows (650 kg of BW, 100 DIM) producing 46.6 kg/day of milk (3.2% fat and 3.0% protein) and consuming 24.9 kg/day DM.

Alfalfa hay was chopped to a theoretical length of cut of 30 mm; corn silage was stored in a bunker silo and sampled on a weekly basis for DM content adjusting its inclusion in the TMR accordingly.

Corn was steam flaked in a vertical stainless-steel chamber at 99°C for 30 minutes, with moisture in the chamber raised to 18% before the corn passed through a pre-heated roller mill (46 × 90 cm in size) to produce flakes (density of 400 g/L). Corn kernels were ground using a hammer mill and passed through sieves with mesh sizes of 2, 3, and 4 mm for the FGC, MGC, and CGC, respectively.

Diets contain steam flake corn increase milk fat content

Results showed that steam flaking and grinding corn grains to different particle sizes had no effect on DM intake, milk production, 3.5% FCM, ECM, fat, or milk protein. Milk fat content however was greater for diets containing steam-flaked corn versus ground corn. Feeding steam-flaked corn and corn finely ground to 0.73 mm improved DM digestibility; however, cows fed steam-flaked corn had lower starch digestibility than cows fed ground corn.

Digestibility of DM and organic matter were greater for fine ground corn and steam-flaked corn than the other diets. In addition, cows fed steam-flaked corn had lower total-tract starch digestibility than cows fed ground corn. Ruminal pH increased, whereas total volatile-fatty-acids (VFA) concentration decreased with steam-flaked corn compared with ground corn diets.

Cows fed steam flaked corn tended to have lower molar proportion of propionate (22.8 vs. 27.1 mM) and total volatile fatty acid concentration (88.6 vs. 99.8 mM) in ruminal fluid than those fed ground corn diets. Ruminal pH (6.46 vs. 6.01) as well as milk fat content (2.75 vs. 2.59%) and efficiencies (fat corrected milk/DM intake and energy-corrected milk/DM intake) were greater for steam flaked corn than ground corn and were not affected by particle size. Milk fat content tended to increase with increasing particle size of ground corn.

Eating activity (min/day) tended to be less for steam flaked corn compared to ground corn. Rumination activity (min/day) and total chewing activity (min/day) were not affected by processing or particle size. Feed efficiency (FCM/DM intake) was greater for diets containing steam-flaked corn compared to ground corn.

This study suggests that steam-flaked corn to 400 g/L density can improve feed efficiency, DM digestibility, and ruminal conditions, resulting in higher milk fat content. In dairy cows producing more than 45 kg/day and DM intake above 24 kg/day, corn flaking may improve rumen health and milk fat content without decreasing milk yield.

Reference

F. Ahmadi, G.R. Ghorbani, A. Sadeghi-Sefidmazgi, M Heydari, H. Rafiee, K.A. Beauchemin. Performance and Feeding Behavior of Dairy Cows Fed High-Concentrate Diets Containing Steam-Flaked or Ground Corn Varying in Particle Size. J Dairy Sci. 2020 Apr;103(4):3191-3203.

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Spelt field

Nutritive value of spelt for ruminants

Alvaro Garcia

Spelt (Triticum aestivum ssp. spelta) also known as dinkel wheat or hulled wheat, is a species of wheat (Triticum aestivum ssp. aestivum) that has been cultivated for over 8000 years. Common in Europe from the Bronze Age to the Medieval Ages, it survives now as a specialty crop in Central Europe and northern Spain.

According to genetic studies it originated as a naturally occurring hybrid of the early wild wheat (emmer; Triticum turgidum) and the wild goat-grass (Aegilops tauschii) even before the appearance of the common bread wheat. Its nutritive value is considered equal if not higher than common wheat. It seems to be resistant to environmental conditions where common wheat does not proper, having even lower nitrogen requirements.

It still retains however most of its characteristics from the past since it has not been genetically improved as intensely. It yields less per hectare, the stems/grain ratio is higher, and it requires additional dehulling than common flour wheat since these hulls represent close to 30% of the kernel.

Spelt is trendy as a healthy food

The recent world “healthy foods” movement has drawn attention back to this species, particularly in Austria, Germany, and Austria, as a specialty flour for human consumption. In other European countries however, it is still utilized as animal fodder particularly in its hulled form. There are also byproducts obtained from its processing for human food that can also be used as ruminant feed.

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