Livestock Production Science 64 2000 121–131 www.elsevier.com locate livprodsci
Genetic correlations of growth, backfat thickness and exterior with stayability in large white and landrace sows
a a ,
b a
´ M. Lopez-Serrano , N. Reinsch
, H. Looft , E. Kalm
a
¨ ¨
Institut f ur Tierzucht und Tierhaltung der Christian-Albrechts-Universitat zu Kiel , D-24098 Kiel, Germany
b
PIC Deutschland GmbH , Ratsteich 31, D-24837 Schleswig, Germany
Received 27 July 1998; received in revised form 2 August 1999; accepted 19 October 1999
Abstract
Backfat thickness, daily gain, and five exterior traits were measured in 36 814 Large White and Landrace gilts from nucleus and multiplier herds. Functional stayability, defined as survived 1 or not 0, from first to second STAY12 and
from first to third litter STAY123 was available for 13 760 of these animals in a commercial multiplier environment. Heritabilities and genetic correlations of longevity and growth performance and exterior traits were estimated by linear
models. Heritability estimates for STAY12 and STAY123 in Large White were 0.08 and 0.10, and in Landrace 0.07 and 0.11, respectively. The corresponding genetic standard deviations for STAY123 were 0.118 and 0.126 in Large White and
Landrace, respectively. Antagonistic genetic correlations were found between stayability traits and backfat thickness and daily gain. Estimates ranged from 2 0.06 to 2 0.32 for daily gain and from 0.11 to 0.27 for backfat thickness in both lines.
Genetic correlations with leg score were about zero in Large White and positive from 0.19 to 0.36 in Landrace, whereas genetic relationships with other exterior traits were near zero. We conclude that the selection for longevity is possible
because of high genetic standard deviations of the stayability traits and that an antagonism exists between growth performance and longevity, whereas a better leg status decreases involuntary culling.
2000 Elsevier Science B.V. All
rights reserved.
Keywords : Sow stayability; Exterior; Growth; Genetic correlations
1. Introduction Many culling reasons in sow breeding have been
reported in the last 20 years and reproductive One aim of selection in pig breeding is to increase
problems appear the dominating cause in productive growth rate and the proportion of valuable cuts. As a
sows, with incidences between 20 and 30 Dij- consequence, exterior is changed and modern pigs
khuizen et al., 1989; Dourmad et al., 1994; Kangas- are longer and leaner, being more susceptible to leg
niemi, 1996; Paterson et al., 1996; Sehested and weakness Van Steenbergen, 1990.
Scherve, 1996. The second most important reason for culling in young sows during the first parity is leg
weakness Dagorn and Aumaitre, 1979; Dijkhuizen
Corresponding author. Tel.: 149-431-880-2590; fax: 149-
et al., 1989; Dourmad et al., 1994; Grindflek and
431-880-2588. E-mail address
: nreinschtierzucht.uni-kiel.de N. Reinsch
Sehested, 1996; Jørgensen, 1996; Kangasniemi,
0301-6226 00 – see front matter
2000 Elsevier Science B.V. All rights reserved. P I I : S 0 3 0 1 - 6 2 2 6 9 9 0 0 1 6 9 - 4
´ 122
M . Lopez-Serrano et al. Livestock Production Science 64 2000 121 –131
1996; Pedersen, 1996, with an incidence of 10–20 generation interval, and to prove a possible relation-
according to Jørgensen and Sørensen 1992. Low ship between the performance traits daily gain and
numbers of piglets produced, old age or death are backfat thickness, and functional stayability in sows.
tertiary causes for sow culling, ranging from 3 to 15 Dijkhuizen et al., 1989; Kangasniemi, 1996;
Sehested and Scherve, 1996. Therefore, replacement
2. Literature overview
of gilts due to lameness is an important cause of economic losses for pig breeders Kroes and Van
Exterior appraisal is used as an indicator for Male, 1979; De Vries, 1989.
longevity in swine and has been used to explain the Leg weakness, using various definitions by differ-
genetic background of longevity in sows. For 30 ent authors, is heritable Smith, 1966; Bereskin,
years linear and non-linear leg traits have been 1979; Webb et al., 1983; Nakano et al., 1987;
already described. Bereskin 1979 working non- Rothschild and Christian, 1988a; Jørgensen and
linearly, found a high heritability for legs of 0.27 in Vestergaard, 1990. A wide range of heritability
Duroc. Webb et al. 1983 defined the leg traits with values is reported in the literature, depending on
an overall leg score in Large White and Landrace statistical methods and breed, varying from low to
boars, and calculated heritabilities for the overall leg moderate between the extreme value of 0.1 Webb et
trait scored in three categories, ranging between 0.13 al., 1983 and 0.47 Rothschild and Christian,
and 0.19 in both lines. Lundeheim 1987 estimated 1988a. Moreover, lameness shows an antagonistic
a heritability of 0.14 on a three-category scale for leg genetic correlation with growth performance Lun-
weakness, higher than the heritability 0.08 of the deheim, 1987; Van Steenbergen, 1990; Stern et al.,
leg status trait defined by three grades in crossbred 1995.
sows by Von Brevern 1996. Rothschild and Christ- Because of its economic value it is important to
ian 1988b also reported, on a scoring system from investigate if a genetic component exists in the
1 to 9, higher heritabilities for soundness and weak- ability of the sow to survive in the herd. Different
ness of legs between 0.29 and 0.42. Jørgensen and definitions are often used as synonymous for surviv-
Vestergaard 1990 found a heritability for overall al: longevity in general, length of productive life in
leg action of 0.45 in Landrace. Schulze et al. 1998 dairy cattle Ducrocq, 1987 and reproductive life-
also worked with a non-linearly scored leg trait from time in sows Van Steenbergen, 1990, and among
1 to 9, and found different and higher heritabilities: the defined survival traits, lifetime and stayability
0.17 for Large White and 0.39 for Landrace boars. Burnside et al., 1984. The last definition will be
Moreover, linearly scored leg traits were also used used in this paper to measure whether or not a sow is
with the same material to include a variation on all alive at a fixed parity in the herd, as defined by
the scores Schulze et al., 1998. These showed Dekkers and Jairath 1994. Until recently, the
similar heritability values and were also similar in estimation of genetic parameters for stayability was
both lines for the traits forelegs or inner claws from not usual in sows, in contrast to dairy cows Schaef-
11 to 30, which are strongly genetically correlated fer and Burnside, 1974; Everett et al., 1976a,b;
with the first non-linearly scored leg trait. A variety Hudson and Van Vleck, 1981; Van Doormaal et al.,
of other linear front-leg traits and hind-leg traits were 1985. However, traits measured earlier in life than
also analysed by Schulze et al. 1998. Heritability stayability, such as exterior traits at gilt stage, could
values of exterior appraisal ranged from 0 to 0.47 be taken as early indicators of longevity, as reported
Van Steenbergen,
1990; Lundeheim,
1996; by Van Steenbergen 1990. They have the advantage
Grindflek and Sehested, 1996, but exterior appraisal in comparison to the stayability traits, which have
is particularly interesting for longevity because the expected low heritabilities and tend to increase the
exterior traits of gait and swinging of back had a generation interval Hudson and Van Vleck, 1981.
heritability of 0.13 and lifetime expectation of 0.16. The aims of this investigation were to estimate the
These were significantly related to culling reasons in heritability of sow survival, to look for exterior traits
sows Van Steenbergen, 1990. as early indicators of longevity in reducing the
Traits such as as length and muscle are also of
´ M
. Lopez-Serrano et al. Livestock Production Science 64 2000 121 –131 123
interest because of their heritability and, moreover, 2710 for Landrace sows, and the total number of
they have a relationship with the leg weakness animals in the pedigree was 24 444 for Large White
syndrome Grøndalen, 1974a. This relationship and 17 255 for Landrace. Selection of gilts was
could indirectly be the cause for culling and con- carried out in the five nucleus farms examining
sequent reduction of longevity. The heritabilities of performance traits and exterior condition at approxi-
linearly scored exterior traits, such as length of back mately 105 kg live weight. The positively selected
and width of hams, representing muscle, were esti- sows were distributed to 65 and 54 multiplier herds
mated and resulted in higher estimates of 28 and for Large White and Landrace, respectively.
36 Van Steenbergen, 1990, respectively. Other The performance traits were daily gain and backfat
objective measurements are available in the literature thickness, registered as weight at selection day
showing higher heritability values due to linearity divided by age in days g day, and as the average
and normality of the chosen traits. Lundeheim value of three points measured at the back mm. All
1987 estimated heritabilities of 0.59 for carcass animals were recorded for these traits. Five exterior
length. Other objective measurements of slaughter traits describing leg status, length, muscle, height
carcass traits, estimated with animal models in boars, and overall type were also scored at the selection day
ranged from 0.35 to 0.7 for lean percentage Johan- using a scale from 1 worst to 9 best. Table 1
nson, 1987; Ducos et al., 1993; De Vries et al., 1994; shows the number of records per exterior trait.
Schmutz, 1995; Engellandt et al., 1997, and from Two categorical longevity traits were defined for
0.34 to 0.44 for carcass length Schmutz, 1995; those sows that were distributed to multiplier farms
Engellandt et al., 1997 in different breeds. and had at least one litter. Survival data from nucleus
The genetic relationship of these exterior traits to sows were not considered because their culling rates
the leg weakness syndrome has been reviewed by are considerably higher due to genetic selection
¨ different authors and may show an indirect relation
Muller, 1997. The number of animals with longevi- to longevity. Lameness as a consequence of the
ty records was 8879 for Large White with 34 668 selected exterior is a reason for involuntary culling.
litters and 4881 for Landrace with 20 023 litters. The There is a relationship between back length and joint
farrowing dates were between July 1987 and April shapes and leg weakness because of joint lesions
1994. The first trait was stayability from first to Schilling, 1963; Grøndalen, 1974a; Lodde et al.,
second litter STAY12 and the second stayability 1985. Some authors have estimated genetic correla-
from first to third litter STAY123, as used previ- tions and concluded that a long body predisposes to
ously in dairy cattle Everett et al., 1976a. A value leg weakness Webb et al., 1983; Lundeheim, 1987;
of 0 was assigned to a culled sow and 1 for a sow Van Steenbergen, 1990. Using subjective visual
surviving up to second or to third litter. All multi- measurements, lower unfavourable genetic correla-
plier sows had an observation for both stayability tions were found between ham score and leg score
values. End of follow-up of the sows for both traits traits r 5 2 0.28 in crossbred sows Von Brevern,
was culling or end of data collection before the
g
1996. Grøndalen 1974b also found a relationship respective second or third parity event. They get a
between back length and possible skeleton problems. zero in all cases if the survival status is unknown.
Stayability records were taken in the first three parities because they have a higher culling rate due
3. Materials and methods to reproductive problems and lameness Dagorn and
