Dr. Billy Flowers - Lauren Christian Endowed Lecture on Swine Reproduction - Sow Longevity

Differences among Commercial
Farms with High and Low
Sow Longevity

W.L. Flowers
North Carolina State University
Raleigh, N.C.

It would be useful to know

to what degree management during the
Developmental and Functional Periods
influence longevity;

and whether Interactions between the
two are present.

Multiplication Farm

High Longevity Farm Low Longevity Farm
28% sows farrow 6 litters 8% sows farrow 6 litters

Birth weight;
Pre-weaning growth;
Post weaning growth;
Body composition; and
Response of vulva to low doses
of gonadotropins @ 140 days of age.

Breeding

Weaning Estrous Scores ;
Rebreeding
Interval
Breeding Scores;
Functional Semen Handling & Quality;
Period Farrowing management;
Lactation
Lactation feed intake;
Gestation
Sow weight change
Sow body composition
changes;
Farrowing Litter characteristics;
Fostering management;
Environmental parameters;
and Feed quality.

Multiplication Farm

512 gilts
(Spring replicate)

256 gilts; rebred after P1 256 gilts; rebred after P1

Multiplication Farm

512 gilts
(Spring replicate)

Characteristics of Gilts delivered to Commercial Sow Farms

230 lbs
6 months of age
No prior boar exposure on Multiplication Farm

Gilts not eligible for delivery included those having poor feet & leg
structures, poor underlines, and infantile vulva.

Entry of Gilts on Farms until First Breeding

Standard operating procedures for both farms are as follows:

first estrus, recorded but gilts not bred;

separate gilts with recorded estrus from non-estrus pool;

breed on second (or later) detected estrus;

after first insemination move into breeding crate; and

2 weeks after last insemination move to gestation crate.

NORTH
Curtain - sides

90 gestation stalls
60 breeding stalls in front of 15
breeding pens
90 gestation stalls

90 gestation stalls
breeding pens 90 gestation stalls
WEST EAST
C
90 gestation stalls

90 gestation stalls

Curtain - sides

SOUTH

Evaporative cooling inlet – 6 ft. x 12 ft. Exhaust fans – 4 ft. diameter
(Cool Cell)

Female Inventory Changes through Rebreeding after First Parity

100
* * p < 0.05
Females remaining in production (%)

90
*
80
* High Longevity
70
60
Low Longevity
50
40
30
E = Entry
20 B = Breeding - gilts
10 F = Farrowing
R = Rebreeding
0
E B F1 R1 F2 R2 F3 R3 F4 R4 F5 R5 F6
Production phase

Entry of Gilts on Farms until First Breeding – Farm Comparisons

High Low
Longevity Longevity

Gilts delivered to farm that are bred 93% 82%
Gilts per pen (12 ft x 12 ft) 8 10
High/Low temperatures in barn (oF) 84/68 83/64

Designated person – gilt estrus/breeding Yes
No
Gilt estrus/breeding separate from sows Yes Yes
Daily boar exposure per pen (min) 15 15

Heat, check boars – age (months) 14 > 24
Heat, check boars – libido good moderate
Periodically collect heat check boars Yes No

Estrous and Breeding Scoring System

Initial Reaction to Boar 1 – Standing reflex immediately
2 – Standing reflex only after back
pressure and handling

Maintenance of 1 – Solid without boar contact
standing reflex 2 – Solid only when boar is in front
3 – Fidgety even with boar in front

Acceptance of 1 – Sow takes semen smoothly
Semen without technician’s help
2 – Sow takes semen with periodic
help from technician
3 – Technician has to work constantly
to inseminate sow

Estrous and Breeding Scores - Gilts

High Longevity Farm
Low Longevity Farm
First Detected Estrus

Initial Reaction to Boar

Maintenance of Standing Reflex
1 2 3

First Mating


Acceptance of Semen
1 2 3

Gestation Management of First Parity Sows


keep sows in breeding crates for two weeks, then move them to
gestation crates;

pregnancy detection is performed via real-time ultrasonography
at 28 days post breeding;

feed levels are adjusted according to body condition as
appropriate

Gestation Management of First Parity Sows – Farm Comparison

High Low
Longevity Longevity

Gestation losses 9% 11%

House gilts together when moved Yes No
Size of group when moving females 2-3 2-3
Person doing moving Designated Random
Method of moving Hands Cutting board

Body condition score prior to farrowing 3.3 3.3

Farrowing Management of First Parity Sows

Standard operating procedures sows are moved into farrowing
crates 3 days before their due date. P1 sows are not induced to
farrow. NORTH

12

11
10

9
8

WEST 7 EAST
C
6

5
4
3

2
1

Hall way

SOUTH

Heater inside each room

Farrowing Management of First Parity Sows – Farm Comparison

High Low
Longevity Longevity

P1 sows not rebred after first lactation 5% 12%

Size of group when moving females 2-3 2-3
Person doing moving Random Random
Method of moving Hands Cutting board
Sows farrowing in gestation barn <1% 5%

Sows assisted during farrowing 15% 3%
Incidence of retained pigs or placenta < 1% 7%
Incidence of post farrowing discharge 2% 2%

Lactation Management of First Parity Sows

Standard operating procedures during lactation are as follows:

sows are fed two to 3 times daily to appetite;

pigs allowed to nurse birth sow for first 24 hours, then fostered
as necessary;

pigs processed on day 1 and males castrated on day 3;

“bump weaning” does occur in order to meet weaning targets.

Lactation Management of First Parity Sows – Farm Comparison

High Low
Longevity Longevity

P1 sows not rebred after first lactation 5% 12%

Average lactation length (days) 19.3 17.8
Weight loss during lactation (lbs) 65.1 73.4
Body condition at weaning 2.3 2.4
Sows that experience a drop in feed intake 7.3% 15.9%
“Bump weaned sows” 15% 20%

Number born alive 11.1 10.8
Number born dead 0.8 0.9
Pre-weaning mortality (%) 9.8 10.5
Number weaned 10.0 9.7

Rebreeding Management


sows weaned into crates;

third day after weaning estrus detection begins;

sows backed out of crates each day into a pen with boars
penned on either side;

first mating occurs in pen;

subsequent matings done in crate with boar in front;

sows bred once each day of estrus.

Rebreeding Management – Farm Comparisons

High Low
Longevity Longevity

Gilts delivered to farm that are bred 5% 12%

Designated person – breeding/estrus No No
Sow estrus/breeding separate from gilts Yes Yes

Heat, check boars – age (months) 14 > 24
Heat, check boars – libido good moderate
Periodically collect heat check boars Yes No

Estrous and Breeding Scores - Rebreeding

High Longevity Farm
Low Longevity Farm
Mating in Pen


Acceptance of Semen
1 2 3
Mating in Crate


Acceptance of Semen
1 2 3

Interaction of Birth Weight of Gilts with Farm Retention
Gilts delivered to farms but not bred (%)

18 High Longevity
Low Longevity

12
* * p < 0.05

6 *

0
< 2.5 lbs 2.6 – 3.5 lbs > 3.6 lbs
Birth Weight Categories

Some aspects of fetal development
probably respond the same way to competition
as pig growth in “crowded pens”.

12 developing fetuses 6 developing fetuses

Birth Weight and Reproductive Performance of Gilts

Piglet Birth Weight (lbs)
Reproductive
Performance 2.0 – 2.8 > 3.5

Age at puberty (days) 188 + 8 170 + 6

Ovulation rate 12.9 + 0.6 15.3 + 0.7

Embryonic survival (%) 69 + 7 83 + 6

(Flowers, unpublished)


Large differences in gilts delivered to farms, but not bred.

High Longevity Farm has designated gilt estrus detection
technician and appears to have better heat check boar
management.

Qualitative assessment of standing reflex and subsequent
mating quality is better on High compared with Low Longevity
farm.


Small differences in females that fall out during first gestation.

High Longevity Farm has designated person to move gilts
from breeding to gestation areas and move fewer animals at
a time compared with Low Longevity Farm.


Large differences in P1 sows that farrow, but don’t rebreed.

High Longevity Farm more aggressive assisting sows during
farrowing and has lower incidence of retained pigs compared
with Low Longevity Farm



Sows on High Longevity Farm have longer lactations; a lower
incidence of short periods of reduced feed intake although
body weight and body condition losses appear to be similar
between the two farms.



High Longevity Farm appears to have better heat check boar
management.

Qualitative assessment of standing reflex and subsequent
mating quality is better on High compared with Low Longevity
Farm for the subsequent mating in stalls.

Multiplication Farm

There probably is a minimum birth weight below
which gilts simply don’t have the reproductive
machinery to function adequately as adults no
matter how well they are managed subsequently.

Graduate Students Undergraduate Students
Dr. Jean Popwell Dr. Chad Smith
Dr. Lauren Job

Charlotte Meli Emily Tosky
Dr. Brad Belstra Dr. Patrick O’Quinn
Jennifer Griffin Dr. Catherine Hefley
Dr. Kara Stewart
Dr. Kyle Lovercamp Dr. Lisa Thompson
Frances Turner Kristey Kenney
Grayson Taylor

Sara Shute Nikhol Garbacik
Shelley Swing Stefani Garbacik

Association of Growth Characteristics with Longevity

Growth Measures R2 P value

Weaning weight (lbs) 0.12 (12%) 0.09

Pre-weaning gain (lbs) 0.22 (22%) 0.03

Post weaning gain (lbs) 0.07 ( 7%) 0.15

Total growth 0.41 (41%)

Other factors 0.59 (59%)

(Flowers et al., in press)

Effect of Neonatal Environment on Female
Response to Early Boar Exposure

Neonatal Environment

Variables < 7 pigs > 10 pigs

Proportion of gilts in estrus 77.0* 53.0
28 days after exposure (%)
†
Average number born 11.3 10.8
alive – early responders

Average number born 10.3 10.2
alive – late responders

* p < 0.05 † p < 0.08

(Flowers et al., in press)

+

LH, FSH

Estrogens

No response
at 140 days of age

Positive response
at 140 days of age

Interaction of Birth Weight of Gilts with Farm Retention

100
Females remaining in production (%)

90
80
70
60
50
40
30 > 3.6 lbs
E = Entry
20 B = Breeding - gilts 2.6 - 3.5 lbs
10 F = Farrowing
< 2.5 lbs
R = Rebreeding
0
E B F1 R1 F2 R2 F3 R3 F4 R4 F5 R5 F6
Production phase (Flowers, unpublished)

There probably is a minimum birth weight below
which gilts simply don’t have the reproductive
machinery to function adequately as adults no
matter how well they are managed subsequently.

While most of the follicles on the ovaries are present
at birth they begin to acquire their functional
competence during the next 30 days – most of which
occurs during their nursing period.

Producers have very little control
prospectively over birth weight, but
can affect pre-weaning growth.

> 10 pigs nursing < 7 pigs nursing

Reproductive Performance and Neonatal Litter Size

100 12

90
11

80

10
70
%

m
w

N
A
B
F
e
g
n
o
a

n
o
e
b
u
v
)
(
r

r
t
i

i
l
60 9

0 0
1 2 3 4 5 6 1 2 3 4 5 6
Sow Parity Sow Parity

< 7 piglets (88.7%) < 7 piglets (11.0 + 0.1)
> 10 piglets (83.3%) > 10 piglets (10.5 + 0.2)

p < 0.05 p < 0.07

Reducing competition during the neonatal period
enhances early ovarian development which improved
longevity.

What can we measure during this period to accurately
assess growth and development of gilts?

Interactions between Birth Weight and Neonatal Litter Size

50
Sows that produced 6 litters (%)

40
*
< 7 piglets
30 > 10 piglets

*
20

10
* p < 0.05

0
< 2.5 lbs 2.6 – 3.5 lbs > 3.6 lbs
Birth Weight Categories (Flowers, unpublished)

Association of Growth Characteristics with Longevity

Growth Measures R2 P value

Weaning weight (lbs) 0.06 ( 6%) 0.14

Pre-weaning gain (lbs) 0.14 (14%) 0.04

Pre-weaning gain / 0.22 (22%) 0.001
birth weight (%)

Total Growth 0.42 (42%)

Other factors 0.58 (58%)


Pre-weaning growth and pre-weaning growth relative
to birth weight appear to have positive associations
with sow longevity and lifetime productivey

The best physiological test for longevity would be
something that mimics what the mature sow asked
required to do effectively each parity.

Effect of Neonatal Litter Size on Response to PG600

Gilts exhibiting vulvar swelling (%) 100 *
80
* < 7 piglets
> 10 piglets
60

* *p < 0.05
40

20

0
80 100 120 140 160
Age of gilts (days)

Strategic use of commercially available gonado-
tropins might be a way to screen for gilts capable
of early puberty without using a boar.

Relationship between Number Born Alive
and Litter Birth Weights

15
Number Born Alive

14
13
12
11
10
9
8

0
10 20 30 40 50
Litter Birth Weight (lbs)

Number Born Alive and Litter Birth Weights
2.5 lb birth
weight
Market animals ?

15 Potential
Number Born Alive

Replace-
14 ment gilts
13
12
11
10
9
8

0
10 20 30 40 50

Number Born Alive and Litter Birth Weights
2.5 lb birth 3.6 lb birth
weight weight

15
Number Born Alive

Strategic
14 Crossfostering Replace-
13 ment gilts
12
11
10
9
8

0
10 20 30 40 50

Source of Replacement Gilts for Commercial Farms in N.C.

Characteristics of Source

Delivered to farm ready to breed 58 %
Purchased from external source 5%
Internal multiplication program 53 %

Delivered to farm prior to breeding age 40 %

Weaned piglets
12 %
Nursery pigs 28 %

No outside delivery – produced on farm 2%

Developmental Period

Periodic assessment
of management
during development.

Dr. Billy Flowers - Lauren Christian Endowed Lecture on Swine Reproduction - Sow Longevity

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