Common Mistakes in Feeding High-Production Dairy Cows

The key to nutrition in high-production cows is managing intake according to their nutritional needs (1). However, mistakes are made in practice that affect health and production. The most frequent ones include:

• Energy Imbalances: Both excess and deficit of energy in the ration are wrong. For example, overfeeding dry cows with concentrates can create “fat cows” with low efficiency and a high incidence of postpartum metabolic diseases (milk fever, ketosis, displaced abomasum) (2). Conversely, diets with insufficient energy limit milk production and deteriorate body condition. Both extremes reduce profitability.

• Lack of Effective Fiber (Long Particles): Rations high in grain and low in structural fiber cause excessive carbohydrate fermentation and subacute ruminal acidosis (SARA) (3). This leads to a drop in intake and production, as well as lameness and liver abscesses (4, 5). Additionally, low fiber reduces milk fat content (6). Conversely, long-fiber forages (coarsely chopped hay, straw) stimulate chewing and salivation, which are natural buffers against acidity (7).

• Abrupt Diet Changes: Abruptly switching from high-fiber rations (pre-calving) to diets rich in concentrates (post-calving) is a classic mistake. The lack of gradual adaptation of the microbial population and ruminal papillae causes pH drops and nutritional instability (8). To avoid this, the introduction of concentrates should be gradual, extending the transition over 2–3 weeks before and after calving (8, 9).

• Poorly Formulated Rations: Omissions or imbalances in protein, minerals, or vitamins affect health. For instance, an excess of calcium during the dry period or a magnesium deficit can precipitate milk fever (10). Inadequate protein levels (or excessive NPN) alter ruminal fermentation. Similarly, exceeding 6–7% added fat can hinder digestion. In any case, the basis of the diet must be high-quality forages, with at least 28% NDF and 18% ADF on a dry matter basis (11), and be supplemented with concentrates formulated to meet requirements at each stage (11, 12).

• Insufficient or Poor-Quality Water: A lack of clean water immediately reduces dry matter intake and production. A dairy cow consumes ~4–5 L of water for every kg of dry matter consumed or ~4–4.5 L per liter of milk produced (13). Water deprivation (or water with excess salts) increases hematocrit, reduces ruminal motility, and causes stress (“aggressive thirst”) (14).

• Deficient Feeder Management: Leaving empty or dirty feeders, or having too little space per cow, leads to competition and irregular consumption. It has been observed that errors in mixing the Total Mixed Ration (TMR) and feeding schedule worsen SARA (15). In general, the feeder should always be kept full (with a ~5% leftover) and water troughs/feeders cleaned daily (15, 16). Providing sufficient space and feeding time for each animal reduces aggression and hungry cows (15, 17).

Each of these mistakes can be critical in intensive, high-production systems; their effects are multiplied in large herds where management must be very careful (16, 18). For example, the FAO recommends that the diet, including fiber, be adjusted to the animal's age, weight, and lactation stage (19), and that all animals have sufficient access to food and water (17). When these global practices are not followed, metabolic problems and efficiency losses quickly appear.

Productive and Health Consequences

The aforementioned mistakes translate into tangible negative effects on the farm:

• Drop in Milk Production: The drop in intake due to acidosis or nutritional stress is usually reflected in fewer liters of milk. The milk fat content (and sometimes protein) also decreases, which indicates a forage/concentrate imbalance (6). Diets rich in grain and low in fiber result in very low milk fat; correcting this by increasing fiber usually restores normal levels (6).

• Subacute Ruminal Acidosis (SARA): This is the most important nutritional disease in dairy farming. It reduces ruminal fermentation, causes chronic low pH, lowers feed intake, and promotes ruminal inflammation. SARA is also associated with chronic frothy bloat and liver abscesses (due to bacteria that cross the inflamed rumen) (5). The clearest pattern of SARA is an irregular “roller coaster” pattern of feed intake and milk production (5, 20).

• Lameness and Hoof Problems: These result from SARA and intermittent bloat caused by low-fiber diets. They manifest as chronic lameness and cows standing less, reducing overall performance (4).

• Ketosis and Loss of Body Condition: This is frequent in animals that are very thin or very fat at calving. It causes anorexia, a drop in milk yield, and rapid weight loss (21). It is often linked to deficiencies in the dry cow diet (negative energy balances at the start of lactation) (22). Prevention includes not over-fattening dry cows and gradually increasing grains before calving (21).

• Hypocalcemia (Milk Fever): The great demand for calcium at the start of lactation (up to 120 g/day) sometimes exceeds the bone mobilization capacity if the dry cow diet was unbalanced (10). Hypocalcemia causes muscle weakness, recumbency, and increases the risk of metritis, retained placenta, mastitis, and displaced abomasum by up to 10 times (23). It also reduces immediate milk production and the animal's productive life (23).

• Reproductive Problems: Nutritional deficiencies have an impact on fertility. A cow that is too fat or too thin takes longer to cycle and conceive. Retained placentas and metritis, with economic losses from subsequent calving delays, are exacerbated in poorly fed herds.

• High Culling and Mortality Rates: In poorly managed intensive herds, metabolic and infectious disorders are frequent. According to university reports, a lack of preventative feeding can lead to losses from death of up to 20–25% of the population in a year (24). This increases replacement costs and affects genetic capital.

In summary, feeding mistakes not only reduce milk yield but also trigger cascades of diseases (metabolic and infectious) that undermine the herd's profitability (23, 24).

Practical Field Examples

• Case 1: Acidosis from Low Fiber. In a commercial herd, a sustained drop in milk fat percentage and frequent lameness in post-calving cows were noted. Analysis of the ration revealed a forage-to-concentrate ratio of only 40:60 and very finely chopped forages. After reformulating the diet by increasing the portion of long hay and slightly reducing the cereals, the ruminal pH stabilized. Sodium bicarbonate (0.6% DM) was also incorporated as a buffer (25). Within a few weeks, milk fat production improved and hoof problems decreased, which is consistent with the idea that "providing fiber of the right level and size usually eliminates the nutritional problems" observed (6).

• Case 2: Error in TMR Mixing. At another large dairy farm, cows showed highly variable intake and a drop in production in specific groups. It was found that the TMR mixer was uncalibrated: inconsistent rations were being formulated for different groups. By retraining the staff, calibrating the scales, and ensuring a homogeneous mixture, consumption patterns became regular. This confirms that "errors in ration calculation and administration" (such as incorrect mixing or scarce availability) exacerbate acidosis (15). After correcting the mixture, production normalized and the cows gained body condition.

• Case 3: Water Stress. A farm in a warm climate observed that in the summer, cows reduced intake and produced less milk. It was found that the drinking water was at a high temperature and in some troughs was saline. By installing cooling systems and ensuring constant automatic replenishment of fresh water, water consumption increased significantly (13). This allowed dry matter intake to be restored to the optimal level. The adjustment yielded quick results, because as the literature notes, a lack of water rapidly affects productive performance (14).

These examples illustrate how seemingly minor mistakes (low fiber, poor mixing, or warm water) translate into losses, and how their correction—based on scientific principles—reverses the problems.

Evidence-Based Technical Recommendations

To avoid the aforementioned mistakes, the following practices are advised (supported by international guidelines):

• Balanced Ration Formulation: Use computer programs or reference guides (NRC, INRA, etc.) to meet the requirements for energy, degradable and undegradable protein in the rumen, fats, vitamins, and minerals at each stage (11, 18). Prioritize periodic analysis of forages and concentrates to adjust actual quantities, avoiding deficiencies or excesses. Ensure that the percentages of NDF (≥28% DM) and ADF (≥18% DM) are adequate (11), and do not exceed 6–7% added fat in the complete diet.

• Effective Fiber and Forage Quality: Include long-particle forages (unchopped hay or coarsely chopped straw) to stimulate rumination. Structural fiber maintains motility and buffers the rumen (7). A ration with high NDF promotes ruminal health, even if it's slightly less energetic (7). Control the quality of silage (avoid bad fermentations) and hay (avoid excessive maturity). According to the FAO, the diet must include adequate fiber and be adjusted to the animal's stage (19).

• Gradual Diet Adaptation: At the start of lactation, increase grains progressively. For example, increase ~0.5–1 kg of concentrate every 2 days in the first week after calving (9). Make intermediate transitions between rations (pre-lactation, low production, high production) when unifeed systems are used (26). Gradual adaptation prevents SARA and ketosis (8, 9).

• Body Condition Monitoring: Maintain cows at appropriate BCS (peak ~2.75–3.0; dry off ~3.5) to avoid both excessive fat pre-calving and cachexia during lactation (2, 22). Recording BCS and adjusting it throughout lactation helps prevent fat cow syndrome or thin cow syndrome and their associated diseases.

• Water Availability in Quantity and Quality: Provide unlimited access to fresh, clean water. As a rule, offer 4–5 L of water for every kg of DM or ~4 L per liter of milk (13, 14). Keep automatic water troughs with floats, clean, in the shade, and with an appropriate water level (5–10 cm margin) (27). The FAO emphasizes that each cow must have sufficient space and time to drink (17).

• Correct Feeder Management: Ensure that feed rations are never depleted; there should always be a 5–10% surplus daily. Adapt the system to the herd's dynamics (e.g., feed TMR at least twice a day). Keep the feeding area clean and offer multiple access points in large groups. Avoid overcrowding cows at a few feeders; provide ~0.60–0.75 linear meters per cow (according to recommended practice). This control prevents stress from competition (15, 17).

• Ruminal Supplements: In diets very rich in concentrate, consider buffers (sodium bicarbonate 0.5–0.75% DM) and additives (live yeasts, probiotics) to stabilize pH (25). These improve intake in fresh cows and help maintain milk fat content (25).

• Training and Clear Protocols: Train staff in heat detection, TMR mixing homogeneity, forage sampling, and feed storage verification. Develop written protocols for each lactation stage. Strict adherence to nutrition guides (NRC, FAO, university extensions) and continuous evaluation of animal response (production, milk analysis, health) are essential.

By applying these scientifically-based recommendations, nutritional mistakes are minimized. In summary, a globally balanced diet, with sufficient fiber and controlled changes, along with good feeder and water management, protects cow health and maximizes production. The FAO and research guides summarize that dairy success rests on precise dietary adjustments for each cow and careful management of the feed supply (16, 19).

Sources: Scientific studies, nutrition manuals, and international guidelines (Merck Vet Manual adapted from NRC, university extensions, FAO, etc.) support the practices described (1, 11, 15, 18, 19).

(1, 7,16, 22) Necesidades nutricionales d el ganado vacuno lechero - Manejo y nutrición - Manual de veterinaria de Merck

https://www.merckvetmanual.com/es-us/manejo-y-nutrici%C3%B3n/nutrici%C3%B3n-ganado-vacuno-lechero/necesidades-nutricionales-d-el-ganado-vacuno-lechero

(2, 4, 5, 6, 9, 10, 18, 21, 23, 24, 25) Salud y enfermedades metabólicas relacionados con factores nutricionales en vacas lecheras (G1743S) https://extensionpublications.unl.edu/assets/html/g1743s/build/g1743s.htm

(3, 8, 15, 20) Acidosis ruminal

https://www.dsm-firmenich.com/anh/es/challenges/supporting-animal-health/rumen-acidosis.html

(11, 12) Formulación de raciones para vacas lecheras

https://es.extension.umn.edu/vacas-lecheras/formular-raciones-para-vacas-lecheras

(13, 14, 27) El agua en la producción lechera | Engormix

https://www.engormix.com/lecheria/nutricion-vacas-alta-produccion/agua-produccion-lechera_a46050/

(17, 19) Guía de buenas prácticas en explotaciones lecheras. Directrices FAO: Producción y Sanidad Animal No.8. Rome

https://www.fao.org/4/ba0027s/ba0027s00.pdf

(26) Recomendaciones para la alimentación de las vacas lecheras | Engormix

https://www.engormix.com/lecheria/suplementacion-vaca-lechera/recomendaciones-alimentacion-vacas-lecheras_a25877/