AARHUS UNIVERSITY Heat stress in farrowing sows under piglet-friendly thermal environments Jens Malmkvist & Lene J. Pedersen Dept. of Animal Science Aarhus University Denmark Abstract page 165
Stress in farrrowing sows kept under a piglet-friendly thermal environment I. Why? II. What is a piglet-friendly thermal environment? (study 1) III. Preferences of farrowing sows (study 2) IV. Effects of floor heating on the sow a. Fully heated pen (study 3) b. Heated pen with colder zones (study 4) V. Conclusion 1
Not a traditional disease model Stress in farrowing sows 2
I. Why? Production economics, Animal welfare Piglet mortality 20-24 % of piglets born EU legislaton, 2013 3
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Early piglet mortality Hypoxia during delivery Hypothermia Insufficient intake of colostrum Crushing by the sow 4
Early piglet mortality Hypoxia during delivery Hypothermia Insufficient intake of colostrum Crushing by the sow 4
Stress in farrowing sows kept under a piglet-friendly thermal environment Stress responses -behaviour -thermoregulation -HPA-axis hormones -farrowing problems piglet vitality and survial 5
Stress in farrowing sows kept under a piglet-friendly thermal environment 6
Stress in farrowing sows kept under a piglet-friendly thermal environment 6
II. What is a piglet-friendly thermal environment Temperatures 18-23 C recommended -avoid thermal stress in sows -optimize feed intake/lactation Neonate piglets thermoneutral zone: ca. 34 C 7
Piglet rectal temperature C 39 38 37 36 35 34 33 32 31 0 2 4 8 24 Hours after birth 8
Piglet rectal temperature C 39 38 37 36 35 34 33 32 31 0 2 4 8 24 Hours after birth 9
Piglet-friendly thermal environment In farrowing pens -heated piglet area away from sow? Not used in early period when the risk of hypothermia is high The piglets prefer to rest at the sow udder the first 2 days postpartum (Herpin et al., 2001; Hrupka et al., 2000; Houbak et al., 2006; Vasdal et al., 2010) 10
Piglet-friendly thermal environment Pen floor heating? 33-34 C at the time of birth Study 1: Malmkvist et al., 2006. Appl. Anim. Behav. Sci. 99. 11
Rectal temp, C 32 34 36 38 40 Floor heating: piglet temperature P < 0.001 Floor heating > Control 0 5 10 15 20 Hours Time after since birth birth, h 12
Propability 1.0 Floor heating: Piglets first suckling 0.8 0.6 0.4 0.2 Effect of treatment: P < 0.01 after 1h Floor heating > Control 0 1 2 4 6 8 Hours after birth 13
Piglet-friendly thermal environment Pen floor heating 33-34 C at the time of birth Favourable for piglets -re-gaining normal rectal temperature -quicker initiation of suckling -increased survival of piglets (1.0 piglet/litter) (Malmkvist et al., 2006) 14
Piglet-friendly thermal environment Pen floor heating 33-34 C at the time of birth Piglets + production economics + animal welfare The farrowing sow? -recommended temp. 18-23 C -floor heating as a stressor 15
Floor heating: Effects on the farrowing sow Heat as an stressor Cooling (17 C) to sows in tropics: Increase feed intake, reduce gestational weight loss, litter weight gain (Silva et al., 2009) Room temperatures at 25 C or above: Marked reduction in daily feed intake (Quinou and Noblet, 1999) 16
III. Preferences of farrowing sows Sows chose 34-35 C heated floor at delivery/first days postpartum (Phillips et al., 2000) Study 2: Pedersen et al., 2007. Appl. Anim. Behav. Sci. 103. 17
Preferences of farrowing sows Heat 34 C, n = 13 Control 20 C, n = 13 Resting area Activity area 18
Preferences of farrowing sows 19
Preferences of farrowing sows No preference/avoidance around farrowing Piglets gradually increased the use of heated floor after 1-2 days postpartum; the sow followed (Pedersen et al., 2007) 20
IV. Floor heating: Effects on the farrowing sow 21
IV. Floor heating: Effects on the farrowing sow a. Fully heated pen (study 3) Study 3: Malmkvist et al., 2009. J. Anim. Sci. 87 22
Floor heating: Effects on the farrowing sow Control Unheated pen floor (n = 14) 21.1 1.4 C Heated Heated pen floor (n = 14) 33.5 1.6 C Heat on Heat off Nest-building + 12h BFP BFP + 48h BFP: Birth of first piglet 23
2nd parity LY sows (n = 28) Room temperature: 21.2 0.8 C Relative humidity: 47.6 8.1 %%, 24
Floor heating: Effects on the farrowing sow N.S. treatment effects on Sow behaviuor Duration of farrowing Interval between piglets Number of piglets at birth (liveborn 15-16, 10 % stillborn) Piglet weight gain 25
Floor heating: Effects on the farrowing sow Lactate in umbilical cord: indicator of hypoxia 26
Lactate, 9 mmol/l Floor heating: Effects on the farrowing sow Modelled for average weight piglet = 1.5 kg 6 4 1 2 4 6 8 Birth duration, hours 27
Floor heating: Effects on the farrowing sow Lactate in umbilical cord: indicator of hypoxia N.S. treatment effect (P = 0.57) Heated: 4.6 (0.23) vs. Control: 4.9 (0.23) No farrowing problems induced by heated floor around farrowing (Malmkvist et al., 2006) 28
Floor heating: Effects on the farrowing sow Veneous catheter Immunological stress indicators: Daily, gestation day 110 until 6 days after farrowing Damgaard et al., 2009. N.S. treatment effects Res. Vet. Sci. 86. 29
Floor heating: Effects on the farrowing sow Veneous catheter ACTH, Cortisol, and Oxytocin: hourly, -8 to + 24 h relative birth of first piglet (study 3: Malmkvist et al., 2009) 30
Floor heating: Effects on the farrowing sow Trend heated > control (P = 0.08) 31
Floor heating: Effects on the farrowing sow Heated > control, P = 0.02 32
Floor heating: Effects on the farrowing sow N.S. treatment effect (P = 0.6) 33
Floor heating: Effects on the farrowing sow Floor heating (33.5 C): acute stressor for sows around farrowing -elevated HPA-axis hormones -no concurrent changes in plasma oxytocin, farrowing problems or sow behaviuor (Malmkvist et al., 2009) 34
Floor heating: Effects on the farrowing sow Positive Stressor Tested at room temperature 21 C Fully heated floor = inescapable 35
Floor heating: Effects on the farrowing sow 36
IV. Floor heating: Effects on the farrowing sow Heated pen with colder zones, 15-25 C (study 4) Study 4: Malmkvist et al., under review 37
Floor heating: Effects on the farrowing sow Room temperature 15, 20, 25 C (n = 72 sows) Heated floor + unheated slatted pen floor 35 C (equilibrium with room temp.) Heat on Heat off Nest-building + 12h BFP BFP + 12h or BFP + 48h BFP: Birth of first piglet 38
Floor heating: Effects on the farrowing sow 180 75 51 5 35 Covered piglet area with heat lamp and floor heating 150 x Concrete floor with heating system x Slatted floor 290 38 11 Sloping leaning wall Feed/water 39
Floor heating: Effects on the farrowing sow Nest-building behaviour 15 > 20, 25 C, P = 0.015 40 30 Room 15 o C Room 20 o C Room 25 o C Nest building, % 20 10 0-24 -16-8 0 8 Time relative to birth of first piglet, h 40
Floor heating: Effects on the farrowing sow No treatment effects on duration of parturition interbirth-intervals umbilical cord lactate litter size until weaning development in body weight in sow/litter 41
Floor heating: Effects on the farrowing sow Daily water consumption 25 >15, 20 C, P < 0.001 60 Daily water consumption, L 50 40 30 20 10 0-7 0 7 14 21 Time in relation to farrowing, days 42
Floor heating: Effects on the farrowing sow Daily Feed Intake Daily feed intake, kg 10 8 6 4 Room 15 o C Room 20 o C Room 25 o C 2-7 0 7 14 21 Days in relation to farrowing 43
Effects of temperature on the farrowing sow Daily Feed Intake, kg 10 8 Room 15 o C Room 20 o C Room 25 o C 6 4 2 0 7 14 21 Weaned per litter: 10 piglets Prunier et al., 1997 Livest. Prod. Sci. 52 9 piglets 44
Effects on temperature on the farrowing sow Prunier et al.,1997 -voluntary feed intake stagnate at 4 days at 27 C -higher gestational weight loss at 27 C -suggested strategy to reduce heat production Present study: -total feed intake the same at 15, 20 and 25 C -no gestational weight loss across temperature -sows appear more heat tolerable 45
Effects of housing system on feed intake and production Danish herd study Loose-housed (n=284) vs. crated sows (n = 288) Loose-housed: Sow feed-intake higher Loose housed: Piglet weaning weight increased (+4%) No difference in weaned piglets (10.4/litter) or weaning age 24 days (Moustsen and Poulsen, 2004) 46
Floor heating: Effects on the farrowing sow Time spent lying laterally 100 NS. effect Time spent lateral lying, % 80 60 40 20 Room 15 o C Room 20 o C Room 25 o C 0-24 -12 0 12 24 36 48 60 72 Time relative to birth of first piglet, h 47
Floor heating: Effects on the farrowing sow Slatted floor use when lying P < 0.005 15 C 20 C 25 C -24 h to + 12h: 13 % < 27 % < 32 % +13 h to 48 h: 6 % < 21 % < 38 % +49 h to 72 h: 6 % = 13 % < 29 % Thermoregulatory behaviour 48
Floor heating: Effects on the farrowing sow Unheated slatted used for lying increase with increasing temperature Farrowing and nesting site? on heated solid floor 15 C: 82 % 20 C: 93 % 25 C: 95% N.S. difference 49
Floor heating: Effects on the farrowing sow Positive Succesfull thermoregulation Tested at room temperature 15-25 C, floor heating 34 C around farrowing. Partly heated floor = colder pen zones 50
V. Conclusion Floor heating: Favourable for neonate piglets born in indoor stables at 20 C (piglets close to sow day 0-2) No sow avoidance/preference at farrowing. Day 1-2 postpartum: sow lying more on heated floor 51
V. Conclusion Inescapble floor heating around farrowing = thermal stressor Behavioural thermoregulation: high thermal tolerance in sows tested at room temperatures15-25 C 52
AARHUS UNIVERSITY Thank you for your attention! Jens Malmkvist & Lene J. Pedersen Dept. of Animal Science Aarhus University Denmark Abstract page 165