Mitigating Impact of Seasonal Loss of Productivity

Dr. Tim SafranskiUniversity of Missouri

(573) 884-7994safranskit@missouri.edu

P.O.R.K. AcademyWorld Pork Expo

June 4th, 2015

Quantifying the Heat Stress Problem

• $300 million annually in U.S.– St. Pierre et al., 2003

• “Seasonality costs me more than PRRS”– Steve Pollman, Director of Operations Murphy-Brown Western Operations

• Wild pig– seasonal breeder– temperature– photoperiod– other

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Describing the Heat Stress Problem

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Thermoregulatory Mechanism of Testis

Rectal temperature:38.24° C (Boar 1)37.75° C (Boar 2)

Testis is 5 to 6°F cooler

Levis

1. Scrotum2. Pampiniform plexus3. Cremaster muscle4. Tunica dartos muscle

Pampiniform plexus: Convolution of veins and arteries for cooling blood entering testis

Effect of season on percent discarded ejaculates

Stud2 Winter (%) Summer (%)

A 6.7 + 1.0 21.4 + 3.4

B 8.2 + 1.3 10.7 + 2.8

C 2.4 + 0.9 18.8 + 3.7

D 4.5 + 1.1 35.4 + 8.9

1% motility or % normal morphology was < 70% in ejaculates not used.

(Flowers,NCR-57,2002, unpublished)

2means are from ~ 2000 ejaculates / stud / season.

Describing the Heat Stress Problem

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Describing the Heat Stress Problem– delayed puberty– weaker, shorter and more irregular cycles– increased embryonic death (if early gestation)

– increased stillborns (if late gestation)

– increased aborts and NIP– decreased lactation feed intake

• decreased piglet growth• increased weight loss• prolonged WEI

– increased sow mortality– I’m running out of room…

Quantifying the Heat Stress Problem

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12/14/05

2/2/06

3/24/06

5/13/06

7/2/06

8/21/06

10/10/06

11/29/06

1/18/07

Date

An

nu

aliz

ed M

ort

alit

y R

ate

(%)

USDA data courtesy Steve Meyer

Influence of season on 28-day RTU Influence of season on 28-day RTU pregnancy diagnosispregnancy diagnosis

NCR-57, 2002NCR-57, 2002

56 herdsSimilar management, facilities, feed & genotype

Daily temperature cycles

HS

TN

Brody Environmental

Center

TN

HS

TN

HS

Gestation and Breeding

Farrowing

RR

RTST

Body weight gain

Least squares means treatments denoted as TN-TN-TN, TN-HS-TN, HS-TN-HS or HS-HS-HS where the series of abbreviations represent the environmental temperature (TN; 18 to 20oC) or heat stress (HS; 24 to 30oC) that the sow experienced in gestation-farrowing-breeding.

Trt P < 0.001Group NSTrt*group NSDay P < 0.001Trt*day P < 0.001

Rectal temperatures

Amanda Minton

Whitney Martin

Trt P<0.036Group NSTrt*group NSDay P<0.001Trt*day p < 0.001

Trt NSSex NSTrt*sex NS

Trt P<0.001Sex P<0.044Trt*sex NS

Trt P<0.001Sex P<0.020Trt*sex NS

a

RR RTST

FI

IGF-I

Milk

Piglet growth

(-) Energy balance

Follicle growth

Body weight loss

Safranski et al., 2013

Does heat stress in utero affect piglets later in life?

28-34°C18-22°C

GTN G

GTN GHS

TN HS

IUTN IUHS

Pro

tein

Acc

reti

on

(g/

d)

60

80

100

120

140

160

180

200A

P < 0.01

IUTN IUHS

Ad

ipo

se :

Pro

tein

(g/

g)

0.5

1.0

1.5

2.0

2.5

3.0

3.5C

P < 0.01

IUTN IUHS

Ad

ipo

se A

ccre

tio

n (

g/d

)

120

160

200

240

280

320

360 B

P < 0.07

Johnson et al., 2014

60-80kg pigs

GTN G

GTN GHS

Wei

ght,

g

Barrow Feed Disappearance

Wilmoth et al., 2014

SE 0.08SE 0.05SE 0.08

GTN G

GTN GHS

From 2-4 months of age progeny gilts (n=165) were evaluated for several measures twice weekly

-At 6am and 2pm rectal temperatures, ear and rump skin temperatures, and respiration rate (RR) were recorded

-Percentage of pigs standing, lying, standing at feeder, standing at water, and sitting was recorded at the top of every hour using video cameras

-Body weights were recorded every three weeks

Lynch et al., 2014

Lynch et al., 2014

Lynch et al., 2014

Lynch et al., 2014

Lynch et al., 2014

Management

• <150d estrous detection with 15 min/d BE

• 6/123 showed estrus within 40d• 81/117 responded to PG-600 (Sept. 28)

• 123 shipped to Suffolk, VA (Oct. 7)

Distribution of PG-600 induced estrus (~69% responded)

Management

• Group housed

• Mated AI to Yorkshire boars

• Limit fed in gestation

• ad lib fed in lactation (2x/d)• Minimal fostering (w/in treatment only w/in 24hr)

• PRRS negative• Mycoplasma and ileitis seropositive (no symptoms)

Production Measures*

GHS GTN

Gestation length, d 115.0 ±.25 114.8 ±.21

Weight at breeding (lbs) 353.26 ± 6.90 353.73 ± 6.69

Gestation weight gain (lbs) 105.46 ± 9.54 101.69 ± 6.40

Lactation weight loss (lbs) 49.99 ± 7.50 41.87 ± 7.54

Lactation Feed Intake*

• tended to differ (P=.07)

– GHS 11.95 ± 0.25 lb/d– GTN 11.31 ± 0.26 lb/d

*>5% difference

Piglet Numbers Per Litter*

a

b

*~3/4 of litters

Piglet Numbers Per Litter*

*all litters; # weaned no longer statistically different

possible carry-over effects of GHS on subsequent reproductive performance of P1 sows. Although not significantly different, P1 sows from GTN farrowed a greater percentage of litters comprised of 13-14 or 15-16 total born compared with P1 sows from GHS

Conclusions

• Direct effect of thermal stress on pregnant females beginning to be understood

• Mediated through the dam, subsequent progeny are also affected

• True cost of heat stress is underestimated– Reduced feed efficiency– Effects on carcass– Reproductive performance and efficiency

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Future Directions

• Assess milk production and composition and whether effects persist to progeny– Michelle Rhoads, VT (funded by Checkoff)

• Intense data collection during pregnancy- Mizzou (funded by Checkoff)

• Endocrine profiles by parity– Not yet funded

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Solving the Heat Stress Problem

• Air conditioning• Check and calibrate ventilation systems

– Fan controls– Inlets– Dusty fan blades reduced flow (80%)– Drippers (0.8 gal/hour)– Cool cells

Solving the Heat Stress Problem

• Use of exogenous hormones

– Label approved• PG-600

– Research setting• prostaglandin• oxytocin

Solving the Heat Stress Problem

• Feed accordingly (especially in lactation)– maximize feed intake– manage cooling systems– wet feed?– feed often or automatic/self feeders