Maintaining Health in Grazing Systems - Livestock Production Notes

Pasture and Transition Management

• Grazing Systems:

  • Set-stocking / Continuous grazing: Low-medium stocking rates for long periods with specific sward height management.

  • Strip grazing: Use of moved fences to control access to fresh grass.

  • Rotational grazing: Movement to new areas every 3–7 days; return intervals of 21–28 days.

  • Paddock / Mob grazing: Movement every 1–3 days with variable return intervals.

• Transition Protocols:

  • Gradual Turnout: Day 1–3 involves short periods ($2$–$4$ hours).

  • Buffer Feeding: Continue offering silage or hay for approximately $10$ days to support the rumen during the switch to high-protein, low-fibre spring grass.

  • Health Monitoring: Observation of appetite, droppings, behavior, and body condition score (BCS).

Poisonous Plants

• Common Ragwort: Causes liver damage and fatal liver failure.

• Yew: Evergreen shrub causing cardiac arrest.

• Bracken Fern: Causes blindness in sheep; acute bleeding or cancer in cattle.

• Oak / Acorns: Causes fatal kidney damage; high risk after storms.

• Hemlock Water-dropwort: Causes rapid, fatal convulsions when cattle ingest exposed roots.

• Foxglove: Contains cardiac glycosides disrupting heart function.

• Rhododendron / Azalea: Leads to vomiting, muscle weakness, and death.

Parasitic Infections

• Nematodes (Roundworms):

  • Teladorsagia circumcincta: Brown stomach worm in UK sheep.

  • Ostertagia ostertagi: Stomach worm in UK cattle causing diarrhoea and weight loss.

  • Nematodirus battus: Affects $6$–$12$ week old lambs in late spring.

  • Haemonchus contortus: "Barber's pole worm" causing blood loss and high mortality.

  • Dictyocaulus viviparus: Lungworm (Husk) causing respiratory issues in calves from July onwards.

• Trematodes and Cestodes:

  • Fasciola hepatica: Liver fluke encysting near mud snail habitats.

  • Moniezia / Taenia Spp: Tapeworms involving mites or carnivore hosts.

• Anthelmintic Control:

  • Group 1 (BZ): White drench (Benzimidazoles).

  • Group 2 (LV): Yellow drench (Levamisoles).

  • Group 3 (ML): Clear drench / Endectocides (Macro-cyclic lactones).

  • Group 4 (AD): Orange drench (Monepantel).

  • Group 5 (SI): Purple drench (Spiroindoles).

  • Lungworm Vaccine: $2$ doses, $4$ weeks apart, completed $2$ weeks before turnout.

Ectoparasites and Fly Strike

• Fly Strike: Greenbottle, blackbottle, and bluebottle flies active March–Dec. Eggs hatch in $12$ hours; maggots reach 3rd stage in $3$ days.

• Nuisance Flies in Cattle:

  • Horn / Stable Flies: Blood-feeders causing pain and reduced weight gain.

  • Face / Head Flies: Transmit Pink Eye and cause irritation/self-trauma.

  • Disease Risks: Transmission of Summer Mastitis and New Forest Eye (NFE).

Mineral Intake

• Hypomagnesemia ($Mg$): "Grass staggers" caused by lush pasture or high $K$ (Potassium) and $N$ (Nitrogen) levels. Symptoms include excitability, spasms, convulsions, and sudden death.

• Trace Elements:

  • Copper ($Cu$): Deficiency leads to poor coat quality and reduced fertility.

  • Selenium ($Se$) & Vitamin E: Deficiency causes White Muscle Disease.

  • Cobalt ($Co$): Required for Vitamin $B_{12}$ production; deficiency causes "Pine" (lethargy/poor thrive).

  • Iodine ($I$): Deficiency linked to stillborn or weak offspring.

Biosecurity and Environment

• Environmental stress: Rapid weather changes increase pneumonia risk. Flooding and dry spells impact pathogen ingestion.

• Vector-borne disease: Midges and ticks spread Bluetongue Virus (BTV), Schmallenberg Virus (SBV), and Babesiosis.

• Biosecurity Measures:

  • Boundary security ($3$-meter gaps).

  • Wildlife control (keeping feed secure from badgers/vectors).

  • Water management (avoiding shared natural water sources).

Questions & Discussion

• Questions: The presentation concluded with a prompt for any questions from the audience.