Case Example 1: Friday: Simherd: This morning: SimFlock - PDF document

Different kinds of simulation Case Example 1: Friday: Simherd: This morning: SimFlock Profitability of using sexed semen: A s tatic and deterministic simulation This afternoon: ”Sexed semen model” Sexed Semen Sexed Semen Economics Small intro: -technique of sexing semen: X-Y -expensive -damaging -90% correct Budgetting: profitability of sexed semen use PhD-side-project: May 2006, Colorado State University Sexed Semen Static-mechanistic approach: 90% heifer calves: -fewer dead born calves -fewer heavy calvings Spread-sheet model to ”simulate the herd” -replacement -expand herd -sell heifer calves -39 biological input parameters: (re)production, culling, calving -sell springing heifers -24 output: calves born, semen used, calving interval, age at first calving -breed cows with beef semen -deterministic and static -quantified with whole-farm-budget Semen costs: -expensive semen -bad conception -extended age at first calving -extended calving interval -multiple use of semen 1

Sexed Semen Economics Partial budgetting: present only the parts of the model that change 1 cow x 1000 = 1 herd Emperical: Disease and production ---x---> replacement Gain: Increasing revenues + decreasing costs Loss: Decreasing revenues + increasing costs Difference: Gain-loss = Profit (if +) or Loss (if -) Deterministic formulas: Conception chance normal semen: 0.6 1.7 ins/preg sexed semen: 80%*0.6=0.48 2.1 ins/preg Whole-farm-budgetting: present all revenues and expenses (US-tool) Age at first calving normal semen: 14mo. + 0.7*21 + 9mo. = 23.1mo. Revenues: milk sexed semen: 14mo. + 1.1*21 + 9mo. = 23.8mo. calves Expenses: feed labour housing Static/Dynamic: Net Return to Assets Profit/loss Models year after year, doesn’t follow a cow Sexed Semen Economics Step 1: parameter estimates Step 2: Estimates relevant prices Normal Semen €11 Normal Semen Sexed semen Conception rate 60% 90% of normal CR Sexed semen €31 Sex ratio ratio (% heifer calves) 49% 90% HF bull calf €188 (1400 DKK ) Twin births 1.85% Probability dystocia, bull calf 24% Beef calf €255 (+500 DKK ) Probability stillbirth, bull calf 20% Heifer raising costs €981 (10 DKK /day) Mortalitity dams, around parturition 2% Lower Risk (RR) for heifer calf 0.6 Springing heifer €1075 (Kælvekvie, DKK 8.000) Dystocia losses €82 Step 3: Design scenarios Results: Technical comparison Default Sexed Semen Difference Sold Default scenario # week-old HF bull calves 503 123 -380 # beef calves (both bull and heifer) 0 495 495 -all nulliparous heifers and lactating cows are bred with normal, dairy semen # springing heifers 100 0 -100 # infertile and aborted heifers 14 11 -3 -all bull calves are sold a.s.a.p. -surplus springing heifers (kælvekvier) are sold for market price Main scenario under study: -all nulliparous heifers with sexed semen - other lactating cows with unsexed, beef semen 2

Results: Budget comparison: € per cow-year Results: Technical comparison Default Sexed semen Difference Default Sexed Semen Difference Revenues Milk sales 2731 2731 0 Sold Beef calves 0 126 126 # week-old HF bull calves 503 123 -380 Cull income 291 289 -3 # beef calves (both bull and heifer) 0 495 495 Week-old bull calves 95 23 -71 # springing heifers 0 -100 100 Spring heifers 107 0 -107 # infertile and aborted heifers 14 11 -3 Loss due to dystocia -9 -8 1 Gross revenue 3215 3161 -54 Bought Sexed semen # ins with sexed semen for heifers 0 673 +673 # ins with sexed semen for cows 0 0 0 Normal semen # ins with normal semen for cows 2165 573 -1591 # ins with normal semen for heifers 781 0 -781 Beef bull semen 0 1591 1591 Total doses of semen 2946 2838 -108 Results: Budget comparison: € per cow-year Time Window: start sexed semen in year 1 Year 1: use of expensive semen, no income from beef-calves Default Sexed semen Difference Year 2+3: income from beef-calves AND income from springing heifers Revenues Milk sales 2731 2731 0 Year >4: expensive semen, income from beef-calves, no income from heifers Beef calves 0 126 126 Cull income 291 289 -3 Week-old bull calves 95 23 -71 Spring heifers 107 0 -107 Loss due to dystocia -9 -8 1 Gross revenue 3215 3161 -54 Default Sexed Semen 980 Expenses Semen costs 32 48 17 970 Net Return to Assets € Replacement costs 463 373 -91 +€33 +€35 Total operating expenses 2037 1964 -73 960 950 +€ 20 +€24 +€20 Gross Margin 1178 1198 20 940 + DKK 146 Fixed ownership expenses 244 244 0 Total expenses 2281 2207 -73 930 920 Net Return to assets 934 954 20 -€15 910 0 1 2 3 4 5 6 Years Results: Sensitivity analysis key-prices and figures Results: Sensitivity analysis key-prices and figures € 1075 Break Even Value €59 Break Even Value €215 3

Discussion: Discussion: Disease complex: costs per case of dystocia: €82 Profitability of sexed semen scenario: €20 per cow/year Simherd: MAS DOWN No uncertainty represented: ALL animals need 1.6 inseminations Of ALL calves born, 6% dies KET Milk price MF MET Livestock prices DA RP Not really in the scope of AHM... DYS No uncertainty represented: €20 Not mechanistic: Replacement rate is set by user -(95% CI: -5, 45) Simherd: replacement rate is a result -Probability of positive result: 75% of disease, reproduction, production, available heifers... Static/deterministic spread-sheet ↔ other budget studies Simherd: Friday Calves per cow-year: -calving interval e.g. 405 days detailed, mechanistic, dynamic, Advantage: -365/405 = 0.90 realistic, stochastic -all cows that calf have 0.9 calves per year First-calf heifers -30% of animals in the herd is a primiparous cow user-friendly-ness, interpretation of Disadvantage: -calving interval does not apply to them results, over-parameterization - higher replacement rate= more first-calf heifers Calves/cow-year is not only dependend on calving interval Static/deterministic spread-sheet ↔ Simherd also on replacement rate Static/deterministic spread-sheet ↔ other budget studies Static/deterministic spread-sheet ↔ other budget studies CPC = (365/CINT) + RR * 0.005 + ε 365/405 + 30% * 0.005 = 0.90 + 0.15 = 1.05 Relation between replacement rate (RR) and calves per cow (CPC)! Calves per cow = 365/CINT SimHerd -run scenarios with different calving intervals IF...replacement rate = 0%!! (CINT) and replacement rates 1.2 1.15 Regression analysis on the outcome: calves per cow-year 1.1 1.05 1 Intercept: CPC = (365/CINT) + RR * 0,005 + ε CINT 405 0.95 CINT 380 Crosses Y-axis 0.9 at (365/CINT) 0.85 0.8 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 replacement rate % 4

Let’s take a look at the spread-sheet -different strategies -introduce stochasticism 5