The Nutritionist 2019 Live and Recorded Ruminant Nutrition Webinars - PowerPoint PPT Presentation

The Nutritionist 2019 Live and Recorded Ruminant Nutrition Webinars More Information at https://agmodelsystems.com/webinars/ Email: webinars@agmodelsystems.com

14 November 2019 9:00 am EST 5:00 pm EST Dr Michael Dineen Teagasc-Agriculture and Food Development Authority Optimizing Productivity From Pasture-based Systems

Cornell University Optimizing productivity from pasture-based systems M. Dineen , B. McCarthy, and M.E. Van Amburgh

Cornell University Introduction • Pasture-based systems • How to maintain pasture quality • Digesta flow experiment • First limiting experiment

Cornell University Competitive advantage • $0.04 lb/DM pasture (rent, fertilizer, reseeding, labor) • For every 2.5% increase in grazed pasture in the cow’s diet, cost of milk production reduced by 1 cent/litre (Dillon et al., 2005) • Key performance targets: – Pasture yield of 15 t DM/ha/year – High grass utilization > 85% – Milk solids output of > 1,200 kg/ha/year – Concentrate supplementation of < 500 kg DM/cow

Cornell University Irish climate • Temperate maritime climate • 46°F during winter time, and about 70 to 75 °F during summer days (Met Eireann 2016) • Eastern half of the country gets between 750 - 1000 mm with the western side receiving between 1000 and 1400 mm of rainfall • Over 90 % of the agricultural area consists of pasture, grass silage or hay, and rough grazing (O’Mara, 2008)

Cornell University Milk Profile 20 500 Calving 3.2% at peak week Concentrate 18 start 450 300-500 kg 16 400 Milk Yield (kg/ha/wk) Feed (Kg Dm /Cow /Day) 14 350 12 300 Grass 4.0 T. DM 10 250 Silage 1.0 8 200 T.DM 6 150 4 100 2 50 0 0 Jan Feb Mar Apr Jun July Aug Sept Nov Dec Jan Feb Month of year

Cornell University Pasture-based system potential • High forage diets – 90-100% inclusion levels • High fiber (30-40% DM) - low starch • Achieve large DMI – 3.5% BW • Produce BW in milk solids – 500 kg MS; fat and protein • Strong reproductive performance – 90% calving in 6 weeks

Cornell University

Cornell University Focus on plant maturity • Immature plant - 1500 kg DM/ha • Post grazing height ~ 4 cm • Leaf/stem/dead ratio • High digestibility but also high productivity 50 kg DM/ha 1000 kg DM/ha 1500 kg DM/ha 2000 kg DM/ha

Cornell University Pre-grazing yield and digestibility Slide courtesy of Dr. Michael O’Donovan

Cornell University Irish Pasture aNDFom Digestion Behavior 12, 30, 120, and 240 h 1 P1 P2 P3 P1 0.9 aNDFom, % DM 36 36 38 P2 0.8 P3 Fast pool, % (kd, %/h) 68 (13) 67 (14) 78 (13) 0.7 uNDFom/aNDFom Slow pool ,% (kd, %/h) 22 (3) 23 (2) 11 (2) 0.6 uNDFom, % aNDFom 9.5 9.9 9.9 0.5 Integrated kd, %/h 7.1 6.6 8.3 0.4 0.3 0.2 0.1 0 0 12 24 36 48 60 72 84 96 108 120 132 144 156 168 180 192 204 216 228 240 In vitro time (h)

Cornell University NY vs. Irish pasture aNDFom digestion NY Pasture aNDFom = 57 % DM Irish Pasture aNDFom = 33 % DM

Cornell University How to maintain high sward quality?

Cornell University You can’t manage what you don’t measure!

Cornell University Pre grazing yield determination • Cut and weigh technique • Quadrat = 0.5 m * 0.5 m • DM/ha = X kg * DM%*40,000 • .100 * .18 * 40,000 = 720 kg DM/ha • .200 * .18 * 40,000 = 1440 kg DM/ha • .250 * .18 * 40,000 = 1800 kg DM/ha • .300 * .18 * 40,000 = 2160 kg DM/ha

Cornell University

Cornell University Grass Wedge • 3 cows/ha (stocking rate) x 17 kg/cow (demand) = 51 kg demand/ha • 5 cows/ha (stocking rate) x 12 kg/cow (demand) = 60 kg demand/ha • 1,550 kg DM/ha – 1,100 kg DM/ha = 450 ÷ 7 days (since last cover) = 64 kg DM growth/day

Cornell University Surplus pasture Picture credit: Farmweek.com

Cornell University 25000 y = 1385.9x + 1811.2 R² = 0.7302 20000 K g 15000 D M / 10000 h a 5000 0 0 2 4 6 8 10 12 14 16 Number of grazings Slide courtesy of Dr. Michael O’Donovan

Cornell University Pasture inventory • Understand feed supply • Forward predict surplus or deficit and make proactive decisions • Maintain pasture quality

Cornell University Utilization

Detrimental knock on effects Graze this To 4cm Next rotation: Cows Leaf grows sward graze leaf down to from 4cm 4cm again upwards Graze this To 5cm Next rotation: Leaf grows sward Cows graze leaf from 5cm down to 5cm, then upwards stem down to 4cm Slide courtesy of Dr. Michael O’Donovan

Cornell University

Cornell University

01-Dec 01-Nov 01-Oct 2015 01-Sep 2016 01-Aug 2017 Cornell University 01-Jul 01-Jun 01-May Growth curve 01-Apr 01-Mar 01-Feb 0 100 80 60 40 20 kg DM/day

Cornell University Yield (kg DM/ha) Paddock # Slide courtesy of Dr. Michael O’Donovan

01-Dec 01-Nov 2016 01-Oct 01-Sep 2017 01-Aug Cornell University 2018 01-Jul 01-Jun 01-May 01-Apr 01-Mar 01-Feb 100 80 60 40 20 0 kg DM/day

Cornell University Target Autumn/Spring Feed Budget 1250 1200 1150 1100 Average Farm Cover (kg DM/ha) 1050 1000 950 900 850 800 750 700 650 600 550 500 450 400 350 31-Jul 14-Aug 28-Aug 11-Sep 25-Sep 09-Oct 23-Oct 06-Nov 20-Nov 01-Jan 15-Jan 29-Jan 12-Feb 26-Feb 09-Apr 04-Dec 18-Dec 12-Mar 26-Mar Week Start Date Slide courtesy of Dr. Michael O’Donovan

Cornell University Pasture nutrient composition

Cornell University Drying protocols for wet chemical analysis • Fresh sample, need to stop respiration immediately! • Freeze drying: – @ −55 °C for 72 h – Gold standard but very intensive • Oven drying: – 95 o C for 15 h - DM only - thermo-chemical degradation – 40 o C for 48 h – loss of nutrients by respiration • 60 o C for 48 h – seems to be a good comprimise

Cornell University How often to sample? CP aNDFom 50 ESC 45 Fat_EE 40 35 30 % DM 25 20 15 10 5 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Week

Cornell University Nutrient supply • Finalizing data on protein fractionation • Water Soluble CHO • aNDFom fractionation OMD • First limiting? – Metabolizable Energy (ME) – Metabolizable Protein (MP)

Cornell University ‘The effect of feeding barley grain on milk production, rumen metabolism and omasal flow of nutrients in lactating dairy cattle fed fresh PRG indoors’ Main objectives: 1. Evaluate the effect of increased fermentable CHO on pasture fed cattle 2. Describe in vivo variables such as aNDFom digestion and N metabolism 3. Quantify protozoal dynamics to help refine the new microbial sub-model

Cornell University Experimental design • Hypothesis: – ↑ CHO = ↑ ME + ↑ MP (↑ microbial protein) • Two treatments – G: Grass only – G+RB: Grass + Rolled Barley (3.5 kg DM, ~20% DMI) • 10 lactating rumen cannulated cows ~500 kg BW • Switchback design comprised of 3 experimental periods – Day 1-20: Adaptation – Day 21-23: Milk production + composition (Infusion) – Day 24-27: Omasal sampling – Day 28-29: Rumen evacuations

Cornell University • Pre cutting yield = 1580 kg DM/ha • Single cut flail mower • 20-30 cm extended length • ~ 10 cm – CSH • Post cutting height = 4 cm

Cornell University Omasal sampling technique (Huhtanen et al., 1997) Photo credit Dr. A. Foskolos

Cornell University Diet nutrient composition Diet Nutrient composition G G+RB RB CP, % of DM 16.3 15.4 11.6 Starch, % of DM 2.2 14.4 60.7 WSC, % of DM 23.9 19.3 1.9 NFC, % of DM 37.7 43.5 65.6 aNDFom, % of DM 36.3 32.7 19.2 12-h uNDFom, % of aNDFom 50.9 - 71.0 30-h uNDFom, % of aNDFom 20.9 - - 72-h uNDFom, % of aNDFom - - 38.5 120-h uNDFom, % of aNDFom 11.8 - 33.0 240-h uNDFom, % of aNDFom 9.9 - - Ether extract, % of DM 3.1 2.9 1.7 Ash, % of DM 6.6 5.6 2.6

Cornell University Milk production and composition 30 G G G+RB SEM P 25 G+RB ECM, kg/d 24.6 24.1 0.8 0.70 20 kg/d Milk fat, % 4.52 4.28 0.16 <0.05 15 10 Milk true protein, % 3.23 3.32 0.07 <0.05 5 MUN, mg/dL 16.5 12.7 0.9 <0.01 0 ECM, kg/d 5.0 4.0 20 P < 0.05 P < 0.05 P < 0.01 G G G G+RB G+RB 4.5 3.5 G+RB 15 mg/dL % 4.0 % 3.0 10 3.5 2.5 5 3.0 2.0 0 Milk fat, % Milk true protein, % MUN, mg/dL

Cornell University aNDFom digestion G G+RB SEM P DMI, kg/d 16.1 17.1 0.4 <0.01 aNDFom intake, kg/d 5.8 5.6 0.2 <0.05 Flow at omasal canal, kg/d 1.6 2.0 0.1 <0.01 Digested in the rumen, kg/d 4.2 3.6 0.1 <0.01 % of aNDFom intake 72.3 63.1 0.9 <0.01 % of pdNDFom intake 80.4 72.3 1.0 <0.01 Total-tract digestibility, % % of aNDFom intake 83.2 74.5 0.6 <0.01 % of pdNDFom intake 92.5 85.4 0.7 <0.01

Microfibrils https://goo.gl/images/8sxdm5

Cornell University CNCPS v.7 ruminal aNDFom digestion prediction Observed Observed 6000 5000 Predicted Predicted +3.5 % -1.1 % 4500 5000 4000 -1.6 % g aNDFom digested g aNDFom digested 3500 4000 3000 3000 2500 2000 2000 1500 1000 1000 500 0 0 G_P2 G_P3 G G+RB