Compost Barn System’s Impact on Dairy: Nutrition, Production, & Milk Quality

Usually, the Compost Barn (CB) system comprises two primary areas:
Resting area with bedding.
Feeding alley with grooved concrete floor.

In certain setups, there might be an additional service corridor designed to assist in directing animals to the milking parlor. Various organic materials have been utilized as carbon sources in the bedding area, including:
Wood shavings and sawdust
Peanut husk
Coffee husk
Wheat straw
Soybean straw
Rice straw

Nevertheless, in areas where the supply is restricted or during material shortages, alternative organic materials have been effectively employed. Occasionally, a mixture of sawdust with soil has been noted, though its efficacy in this context lacks proven evidence. In this system, both feces and urine are deposited and integrated into the organic material within the bedding area.

The integration of animal waste takes place while turning the bedding material, utilizing an implement (such as a subsoiler, rotary hoe, etc.) attached to the tractor.

The turning of the bedding material should occur at least twice a day when cows are being milked.

However, under certain circumstances where labor is scarce, producers may opt to confine the cows in the feeding alley before the bedding turning process. This procedure seeks to loosen the surface material, encourage the blending of bedding and waste, enhance porosity (void space), and elevate oxygen concentrations within the bedding material.

Failure to conduct regular and proper turning can result in bedding compaction, diminishing oxygen availability for decomposing microorganisms and impeding material degradation.

Oxygen supply is essential for the satisfactory aerobic decomposition of bedding material, and its demand increases with the degradation speed.

Dietary Requirements of Dairy Cows in the Compost Barn System

The housing system for dairy cows should offer improved thermal comfort and increased flexibility for producers dealing with groups of animals in the same physiological stage. Among various confinement systems, the Compost Barn (CB) has demonstrated superior welfare conditions and enhanced flexibility when managing groups of animals at similar physiological stages.

European dairy breeds specialized for high milk production are particularly susceptible to heat stress, a prevalent condition in Brazil given its tropical climate. Dairy cows with elevated milk production require conditions that allow them to fully express their genetic potential, including:

An environment with adequate comfort
Access to water and feed intake
Comfortable beds that increase resting time
Facilities that provide good thermal comfort conditions

Heat stress initiates metabolic and behavioral changes in the herd. In practice, it has been observed that in conditions of thermal discomfort, cows reduce dry matter intake and spend more time standing, increasing their respiratory rate in an attempt to dissipate body heat to the environment.

All these conditions result in higher energy expenditure during this interval of reduced dry matter intake, leading to lower milk production, directly affecting animal health. Another behavioral factor that increases during heat stress is feed selection at the trough, which can be a risk factor for acidosis in animals and a decrease in milk solids content.

Additionally, if lactating cows do not lie down for at least 12 hours a day, it will also lead to reduced production. In other words, for each additional hour of rest, cows will produce 1.6 liters more milk per day.

Dairy cows possess nutritional requirements for both maintenance and production, with these requirements varying according to their physiological condition. Throughout the transition period, which spans 21 days before calving and 21 days post-calving, the primary focus of nutrient demand is on:
Fetal growth
Mammary gland preparation in the last days of gestation
Colostrum production, and
After calving, milk synthesis

A vital aspect during the transition period is the eating behavior of cows, as physical, behavioral, environmental, physiological, and metabolic changes in the animal significantly impact performance. Each additional liter of milk achieved during the lactation peak contributes to an extra 200 liters of milk throughout lactation. It’s crucial to emphasize that the maximum feed intake by animals occurs only when cows have adequate time for their meals.

Production of Dairy Cows in the Compost Barn System

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