Pasture-Based Farming Systems

Classification: Dairy farms are classified into five systems based on feed intake levels.
System 1 (All Grass): Relies entirely on grazing within the dairy platform. No grazing off-site or adjustments. Managed by growing and grazing feed on the land.
Increasing Feed Import: Systems transition from all-grass to incorporating imported feed to meet lactating cows' high energy demands.
Feed Composition: Imported feed can constitute up to 50% of the diet, including corn feed.
Buffering: Imported feed serves to buffer feed requirements during shortages.

Organic Treatment: Addressing animal sickness organically involves attempting organic treatments until they prove ineffective.
Removal from System: If an animal doesn't respond to organic treatment, it must be removed from the organic production system.
Certification: Production systems must be certified by bodies like BioGro New Zealand and AsureQuality to market products as organic.

Prevalence: Pastoral systems (sheep, cattle, goats, deer) are common due to the temperate climate and grass growth.
Ryegrass: Perennial ryegrass is the primary pasture species, typically grown with white clover.
Nutrient Base: Ryegrass has a reasonably high nutrient base, though not the highest among green feeds.

Seasonal Variation: Pasture growth varies throughout the year, peaking in spring (November) and declining in summer (January, February) and winter (June, July).
Surplus in Spring: Spring often sees more grass growth than animals need.
Managing Surplus: Managing surplus grass in spring is crucial for maintaining high-quality feed in winter and summer.
Specialist Crops: Specialist pastures and crops are used to ensure high-quality feeding during winter and summer.

Regional Variation: Pasture growth varies by region due to differences in rainfall.
Regional Knowledge: Farmers need to know what's normal in their region.
Pasture Growth Forecasters: Tools like pasture growth forecasters (e.g., DairyNZ) can provide estimates, but farmers also keep their own records.

Growth Rate: Pasture growth is measured as a growth rate (kilograms per unit of time).
Dry Matter: Measured as kilograms of dry matter (DM) per hectare per day (kg DM/ha/day).
Dry Matter Definition: Dry matter is what remains after removing moisture from the grass.
Composition: Grass typically consists of about 80% water, with the remaining dry matter including carbohydrates, fats, vitamins, and secondary compounds.

Plant Quality: Seasonal changes affect not just the amount of plant growth but also plant quality and nutrient value.
Structural Carbohydrates: Plants contain structural carbohydrates like cellulose and hemicellulose, which provide support.
Mammalian Digestion: Mammals can't directly digest these structural carbohydrates because they lack the necessary enzymes.
Ruminant Digestion: Bacteria in the rumen of ruminant animals can utilize structural carbohydrates.
ADF and NDF: Acid Detergent Fiber (ADF) and Neutral Detergent Fiber (NDF) are measures used to quantify structural carbohydrates.
$ADF$ : Correlates negatively with digestibility; higher $ADF$ indicates lower digestibility.
$NDF$ : Relates to the amount of fiber in the feed; influences feed intake.
Soluble Carbohydrates: Summer sees a decrease in soluble carbohydrates (easily fermentable and digestible) and an increase in structural components.

Managing Surplus: During grass surpluses (e.g., spring), strategies include drying off cows early or switching to once-a-day milking to reduce consumption.
Strategic Grazing: Employing methods like strip grazing to maximize grass utilization.

Brassicas: Winter crops like brassicas (swedes, forage kale) are grown to provide feed.
Silage: Fermented grass stored in plastic.
Hay: Dried grass, often baled and wrapped in netting or plastic.
Maize Silage: Stored in large pits, covered with plastic and tires.
Concentrates: Various concentrate feeds are used.

Varied Feeding Values: Different feeds have different feeding values.
Range of Values: Some feeds have high feeding values, while others have moderate to low values.