Irrigated farming systems Nutrition and animal health considerations

Transcription

1 27 July 2018 Irrigated farming systems Nutrition and animal health considerations D Squibb and C Westwood PGG Wrightson Seeds

2 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?

3 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!

4 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

5 More digestible, lower NDF Inherent forage attributes Changed management rotational grazing, lower pre-graze mass More digestible, higher energy = fewer kgdm/g or kg liveweight gain, increased efficiency BUT 1. Less pendf (cattle) 2. Faster rumen outflow rate (ROR)

6 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

7 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

8 Faster rumen outflow rate (ROR) irrigation Young stock More fermentable carbs to intestines 1. Clostridial disease (vaccinate) lambs, calves 2. Redgut lambs lucerne (red clover?) small rumen capacity Fibre supply on-off graze grass, baleage 3. Academically lower MJME/kgDM as less fermented rumen, more hindgut

9 High crude protein (CP) Depends on Soil mineralisable nitrogen (N) Nitrogen fertiliser Pasture or crop species Management Typically greater crude protein concentration vs dryland

10 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

11 Other possible challenges Low pendf Tryptophan toxicity Rapid Rumen outflow rate Bloat Pulpy kidney SUDDEN CHANGE TO HIGH QUALITY PASTURES High crude protein High faecal moisture (fleece staining) Vitamin B1 deficiency (Polioencephalomalacia PEM or PE ) Internal parasite larval challenge Footrot fine wool breeds

12 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

13 SUMMING UP

14 Top three take home messages Challenges are manageable! Think of irrigated pasture as a crop changing from lesser quality dryland Gradual adaptation from dryland to irrigated pastures especially during late spring and summer if not closed system Clostridial vaccination for young stock

15 Tools, resources and training Pasture Principles Macquarie Franklin Facebook groups 1. The Rumen Room 2. The Forage Forum

16 Thank you David Squibb PGG Wrightson Seeds Aust Mobile Charlotte Westwood PGG Wrightson Seeds NZ Mobile