Joseph Stock - Objective Feet & Leg Structure between Selection & Second Gestation & Gestation Ages

IOWA STATE UNIVERSITY
Department of Animal Science
Objective feet and leg joint structure
between selection and second
gestation and gestation ages
J.D. Stock1, J.A. Calderón Díaz1,2, B.E. Mote3,4,
K.J. Stalder1
1Department of Animal Science, Iowa State University, Ames, IA 50011
2Department of Animal Behaviour and Welfare, Institute of Genetics and
Animal Breeding, Polish Academy of Sciences, ul. Postepu 36A,
Jastrzębiec, 05-552 Magdalenka, Poland
3Fast Genetics, Saskatoon, SK, S7L 7E1
4University of Nebraska – Lincoln, Lincoln, NE 68588

General Introduction
Studies have reported that feet and leg
problems are the second leading reason for
culling among sows with up to 20.3% of
removals due to leg problems
(Dagorn and Aumaitre, 1979; Stein et al., 1990; Cederberg and Jonsson, 1996;
Sehested and Schjerve, 1996; Boyle et al., 1998; Anil et al., 2005; Mote et al., 2009)
This is likely an underestimate as feet and leg
problems affect other traits that could be used as
reason for removal

General Introduction
Selection for optimal feet and leg conformation
traits improves sow longevity
Visual appraisal methods that rely on trained
individuals to score an animal on a categorical
scale have been previously developed
 Multiple systems that are similar, but different
 Vulnerable to varying degrees of bias and error
associated with the ability of the scorer (Main et al., 2000;
Van Nuffel et al., 2009; D’Eath, 2012)

NSIF Structural Scoring Guide
NSIF 2002-2003
Takes
experience to
differentiate
between two
individual
scores.

Introduction
 Final selection of breeding females occurs at
roughly 20 weeks of age (140 days)
 Still undergoing rapid growth during this age
 Life events, such as gestation, which adds significant weight,
have not been able to be evaluated for potential effects on
structure
 Female replacements do not reach their mature
physical size until after their second parity (Robison,
1976)
 Consequently, most females are removed for feet and leg
problems during the time period between selection and
second parity (Mote et al., 2009)

Introduction
 Few studies have examined structural change
over time in swine
 Fernàndez de Sevilla et al. (2009) observed six feet
and leg conformation traits between time at
selection and their second parity
 Sickle hocked rear legs became more prevalent with age
 Pasterns became straighter between selection and first
parity
 No studies were found to have examined
structural change during gestation

Objectives
Evaluate feet and leg joint angle
measurements between time of selection
and after their first parity
Evaluate feet and leg joint angle
measurements across gestation days

Materials and Methods
319 maternal gilts at selection
Age at measurement ranged from 19 to 25 weeks old
277 remained post 1st parity
Gestation days ranged from zero to 87
Average gestation 26.7 ± 17.2 days

Animals by Analysis
Parity 0 – Parity 1
Females with repeated records from selection and post
1st parity were used (126 total females)
Only females in their first 21 days of gestation post 1st
parity were included
Parity 2 farm and gestation age
All 277 females post 1st parity are included

Material and Methods
ImageJ software was used to take feet
and leg measurements from the images
Phenotypic traits (angles) are measured
in degrees
Knee
Front and rear pastern
Hock
Rear stance

Profile diagram of joint angles measured
a & b – knee; c & d – front pastern;
e & f – hock; g & h – rear pastern

Rear stance diagram angles measured
a & b – rear stance

Parity 0 – Parity 1 Analysis
Proc Mixed from SAS® software was used
Fixed effects
Parity, side of measurement
ID was used as a random effect
Parity was used as a repeated variable
Results
Fixed effects = LS means ± SE

Parity 2 Farm and Gestation Age Analysis
Proc Mixed from SAS® software was used
Fixed effects
Farm, side of measurement
Linear covariate
Gestation Age (days)
ID was used as a random effect
Results
Fixed effects = LS means ± SE
Linear covariate = Reg ± SE

Difference between selection and 1st parity
1 Parity is repeated from selection (0) to first parity (1) for 126 females
2 Side is measured from the left and right profile images for the knee, front and rear pastern and the
hock, rear stance does not have a side variable
a,b Values in a column without common superscript are significantly different (P < 0.05)
Knee
Front
Pastern
Rear
Pastern
Hock Rear Stance
Variable
LS
Means
SE
LS
Means
SE
LS
Means
SE
LS
Means
SE
LS
Means
SE
Parity1
0 160.2a 0.2 57.0a 0.5 58.5a 0.5 140.5a 0.4 91.4a 0.6
1 159.4b 0.2 56.1a 0.5 53.3b 0.5 146.4b 0.4 86.5b 0.6
Side2
L 160.0a 0.2 56.9a 0.5 56.0a 0.5 142.8a 0.4
NA
R 159.5a 0.2 56.2a 0.5 55.8a 0.5 144.1b 0.4

Farm and gestation differences second gestation
1 Sows were distributed across three farms, farm A (82), farm B (98), and farm C (97)
2 Side is measured from the left and right profile images for the knee, front and rear pastern and the
hock, rear stance does not have a side variable
a,b Values in a column without common superscript are significantly different (P < 0.05)
Knee Front Pastern Rear Pastern Hock Rear Stance
Variable
LS
Means
SE
LS
Means
SE
LS
Means
SE
LS
Means
SE
LS
Means
SE
Farm1
A 159.0a,b 0.3 55.6a 0.6 51.4a 0.6 146.4a 0.5 82.5a 0.7
B 158.5a 0.3 58.2b 0.6 54.5b 0.6 147.4a 0.5 88.4b 0.7
C 159.5b 0.3 57.5b 0.6 55.8b 0.6 147.6a 0.5 88.5b 0.7
Side2
L 159.4a 0.2 57.9a 0.4 54.5a 0.4 147.8a 0.3 NA
R 158.6b 0.2 56.3b 0.4 53.3b 0.4 147.5a 0.3 NA
Gestation
Age3 -0.02 ± 0.01* 0.04 ± 0.02* 0.02 ± 0.02 0.05 ± 0.02* -0.01 ± 0.02

Discussion
Rear pastern angles decreased
(weakened) and hock angles increased
(straightened) between selection and 1st
parity
Rear stance also decreased between
selection and first parity
May be due mostly to farm difference in second analysis
Side was only significant for the hock,
however difference is small

Discussion
Farm differences were found in the knee, front
and rear pasterns and to the highest degree in
the rear stance between farms A and B,C
Could account for parity difference in rear stance
Side was significant for the knee, and front and
rear pastens
Angle difference are small and are still most likely not
biologically important

Discussion
Gestation age showed significance in the
knee, front pastern and hock angles
Knee angle values decreased over gestation days
Front pastern angle values increased over gestation
days

Conclusions
As age increases structure changes, with rear
leg joints showing greater variation than the
front leg
Front leg differences across age are generally
small
Results suggest that environmental factors,
such as farm, can contribute to angle
differences
Small angle changes over time could indicate
structure that carries over the life of the female

Conclusions
Rear leg structure still requires further
investigation
Fernàndez de Sevilla et al. (2009) stated, “The
detection of genetic components in leg
conformation and specific leg defects in sows
should prompt further research into the
genetic architecture of morphological traits in
sows.”
 The results of our study were in direct contradiction to the
results found in that study and further validates the need to
look further into genetic aspects of structure change over time

Ongoing and Future Work
Gestation structural changes are being
examined in more detail within an
individual
Evaluation within an individual will carry
over for three parities and include
pedigree information for genetic analysis

Acknowledgments
Fast Genetics
Farm Employees

Questions
Thank you for your time and attention!
Are there any questions?

Joseph Stock - Objective Feet & Leg Structure between Selection & Second Gestation & Gestation Ages

Recomendados

Recomendados

Mais conteúdo relacionado

Semelhante a Joseph Stock - Objective Feet & Leg Structure between Selection & Second Gestation & Gestation Ages

Semelhante a Joseph Stock - Objective Feet & Leg Structure between Selection & Second Gestation & Gestation Ages (20)

Mais de John Blue

Mais de John Blue (20)

Último

Último (20)

Joseph Stock - Objective Feet & Leg Structure between Selection & Second Gestation & Gestation Ages