Nutrition and animal health considerations · – cattle 35% – lambs 28–30% • Cattle anissue,...
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Irrigated farming systems Nutrition and animal health considerations D Squibb and C Westwood PGG Wrightson Seeds 27 July 2018
Transcript of Nutrition and animal health considerations · – cattle 35% – lambs 28–30% • Cattle anissue,...
Irrigated farming systemsNutrition and animal health considerations
D Squibb and C WestwoodPGG Wrightson Seeds
27 July 2018
Irrigation and paradigm shifts
• Irrigation = opportunities
• Increased dry matter (DM)/ha and stocking rates
• Pasture persistence
• Novel forages and enhanced feed value
• Too good to be true?
Irrigation planning and implementation
• financing / investment / infrastructure / agronomics / stock class changes
• Presumption new forage = productivity/profit• Sometimes…
– reduced feed conversion efficiency (FCE)– increased health issues (on ‘knife edge’)
Issues are manageable!
Planning to manage new forages
• Novel forage types — new grazing management
• Forage types grasses, legumes, herbs, annual crops– Higher digestibility and energy
(MJME/kg DM and MJME/ha)– Lower neutral detergent fibre
(NDF) and less effective? – Higher crude protein
More digestible, lower NDF
• Inherent forage attributes• Changed management —
rotational grazing, lower pre-graze mass
• More digestible, higher energy = fewer kgDM/g or kg liveweightgain, increased efficiency
BUT1. Less peNDF (cattle)2. Faster rumen outflow rate (ROR)
Less peNDF
• Less NDF and lower peNDF• NDF:
– cattle 35%– lambs 28–30%
• Cattle anissue, less so lambs• SARA rare, questionable clinical
consequence?• Susceptibility to ruminal bloat? • Manage grazing rotation length,
high peNDF supplementary feed
Rapidly rumen fermentable — irrigation
• Fast breakdown, plant cells• More VFA production (SARA??) not lactic acid• Grasses less issue• Legumes (red/white clovers/lucerne) BLOAT
– bloat oils– supplementary fibre– wilting– cattle not hungry– shift later in day
Faster rumen outflow rate (ROR)–irrigation • Young stock• More fermentable carbs to intestines1. Clostridial disease (vaccinate) lambs, calves2. Redgut lambs lucerne (red clover?) small rumen capacity Fibre supply on-off graze grass, baleage3. ‘Academically’ – lower MJME/kgDM as less fermented rumen, more hindgut
High crude protein (CP)
Depends on• Soil mineralisable nitrogen (N)• Nitrogen fertiliser• Pasture or crop species• Management • Typically greater crude protein
concentration vs dryland
High crude protein (CP)
Usually = GOOD thing• Prime lambs, heavily in lamb and lactating ewes,
yearling cattle 14–18% CP• Too much of a good thing? • Rumen and liver adaptation – up to six weeks +• Less issue, always on irrigated pasture• Greater issue, change dryland quality to irrigated
Other possible challenges
SUDDEN CHANGE TO HIGH QUALITY
PASTURES
Low peNDF
Rapid Rumen outflow rate
High crude protein
Internal parasite larval challenge
Vitamin B1 deficiency (Polioencephalomalacia’
‘PEM’ or ‘PE’ )
Bloat
Tryptophan toxicity
High faecal moisture (fleece staining)
Footrot fine wool breeds
Pulpy kidney
So, irrigated pastures are different? Often yes, vs. dryland • Poor feed conversion efficiency and/or health
challenges • Dryland stock to irrigation for finishing esp late
spring/summer months• Set stocking for lambing / calving
Think irrigated pastures as ‘crop’• May need ‘transition’ rumen and liver adaptation
dryland to irrigated new pasture species• Better if stock remain on irrigated pastures
SUMMING UP
Top three take home messages
Challenges are manageable! Think of irrigated pasture as a ‘crop’ changing
from lesser quality drylandGradual adaptation from dryland to irrigated
pastures — especially during late spring and summer if not closed systemClostridial vaccination for young stock
Tools, resources and training• Pasture Principles – Macquarie Franklin• https://www.evergraze.com.au/library-content/feedbase-
planning-and-budgeting-tool/
• https://www.mla.com.au/extension-training-and-tools/tools-calculators/health-cost-benefit-calculator/
• https://www.mla.com.au/extension-training-and-tools/tools-calculators/stocking-rate-calculator/
• Facebook groups1. The Rumen Room2. The Forage Forum
Thank you
David SquibbPGG Wrightson Seeds Aust
Mobile 0425790222Email [email protected]
Charlotte WestwoodPGG Wrightson Seeds NZ
Mobile +64275544541Email [email protected]
