dr. tim safranski - mitigating impact of seasonal loss of productivity
TRANSCRIPT
Mitigating Impact of Seasonal Loss of Productivity
Dr. Tim SafranskiUniversity of Missouri
(573) [email protected]
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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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(Flowers,NCR-57,2002, unpublished)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– 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
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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
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
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
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
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)
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
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