Livestock Production Science 68 2001 67–77 www.elsevier.com locate livprodsci
Reproductive performance of purebred Hampshire sows in Sweden
a,c , b,c
a,c a,c
P. Tummaruk , N. Lundeheim
, S. Einarsson , A.-M. Dalin
a
Department of Obstetrics and Gynaecology , Faculty of Veterinary Medicine, Landscape Planning and Horticulture,
Swedish University of Agricultural Sciences SLU, Box 7039, SE-75007 Uppsala, Sweden
b
Department of Animal Breeding and Genetics , Faculty of Agriculture, Landscape Planning and Horticulture,
Swedish University of Agricultural Sciences SLU, Box 7039, SE-75007 Uppsala, Sweden
c
Centre for Reproductive Biology in Uppsala CRU, Uppsala, Sweden
Received 26 November 1999; received in revised form 3 April 2000; accepted 22 May 2000
Abstract
The objective of this study was to retrospectively investigate causes of variation in the reproductive performance of purebred Hampshire sows in Sweden. Data analysed comprised farrowings between 1992 and 1998 from five Swedish
nucleus herds and included 6347 litters from 2210 sows. The main traits analysed were litter size, weaning-to-first service interval WSI, farrowing rate, remating rate and age at first farrowing. Analysis of variance was used for the statistical
analysis of continuous data. Logistic regression was applied for categorical data using the GLIMMIX macro of the SAS programme. Factors included in the analyses were parity number, herd, year within herd, lactation length and month of the
year season. On average, Swedish Hampshire sows had 9.8 total piglets born litter, 9.0 piglets born alive litter, a WSI of 5.0 days, a 22 remating rate, a 68 farrowing rate and were 386 days of age at first farrowing. Parity influenced litter size
at birth P
, 0.001 and WSI P , 0.01. Season influenced P , 0.001 WSI, farrowing rate and age at first farrowing, but not litter size. However, the interaction between season and parity for litter size was significant. A longer lactation length
resulted in a shorter WSI but the interaction between lactation length and season for WSI was significant P , 0.001. WSI
influenced subsequent number of total piglets born litter P , 0.01, farrowing rate P , 0.001 and remating rate
P , 0.001.
2001 Elsevier Science B.V. All rights reserved.
Keywords : Pig; Hampshire; Reproduction; Season; Parity; WSI
1. Introduction
In Sweden, the Hampshire breed is mainly used as a sire line in commercial herds Simonsson and
Corresponding author.
Department of
Obstetrics and
Rydhmer, 1996. The Hampshire boars are produced
Gynaecology, Faculty of Veterinary Medicine, Swedish University
by Swedish nucleus herds, which are at the top of the
of Agricultural Sciences, Box 7039, SE-75007 Uppsala, Sweden.
Swedish pig breeding structure. To our knowledge,
Tel.: 1 46-18-672-904; fax: 1 46-18-673-545.
E-mail address : padet.tummarukog.slu.se P. Tummaruk.
only a few studies on the reproductive performance
0301-6226 01 – see front matter
2001 Elsevier Science B.V. All rights reserved. P I I : S 0 3 0 1 - 6 2 2 6 0 0 0 0 2 0 7 - 4
68 P
. Tummaruk et al. Livestock Production Science 68 2001 67 –77
of the Hampshire breed have been reported Rico, east. The variation within year in outdoor tempera-
1988 and no such study has been made in Sweden. ture as well as in photoperiod is relatively high for
It is well established that productivity of an this region. The outdoor temperature 24-h averages
individual sow depends on a number of reproductive in this area recorded during a period of 1994 to 1997
parameters, such as litter size at birth, weaning-to- ranged from a minimum of
2 14.48C in winter to a first service interval WSI and conception rate
maximum of 26.6 8C in summer. Day length varied
Britt, 1986; Stein et al., 1990. The variation in from about 18.6 h in June to 5.9 h in December.
these parameters is influenced by both genetic back- However, Swedish swine producers usually try to
ground of the sow reviewed by Rothschild and control the variation in photoperiod by supplying
Bidanel, 1998 and environmental factors, such as artificial light to give approximately 14–16 h light
management and season Clark and Leman, 1986; day in the sow units throughout the year. To obtain
Dewey et al., 1995. Significant interaction between information concerning herd management, directed
genotype of the sow and environmental factors has questionnaires were distributed to the herds included
been observed reviewed by Christenson, 1986. in the data analysed. For all herds, gilts were mated
Recent studies have demonstrated that reproductive in their second observed oestrus or later at about 7 to
characteristics of Swedish Landrace and Swedish 9 months of age. In most herds, dry sows were
Yorkshire sows are differently influenced by factors grouped in loose-housing systems with deep straw
such as season, parity and mating type Tummaruk et bedding and individual feeding, whereas lactating
al., 2000a,b. Although the Hampshire breed is used sows were kept separately in farrowing pens. Preg-
mainly as a sire line in crossbreeding, information nancy detection was performed about 4 weeks after
about their reproductive performance as purebreds is mating. Batch-wise production was performed in all
still of great interest. A number of studies has shown herds, i.e., a group of sows entered the farrowing
that the Hampshire breed has a smaller litter size unit on the same day, and all sows in that batch were
than the European white breeds, such as the Land- weaned on the same day. After weaning, the sows
race or Yorkshire Schneider et al., 1982; Bass et al., were immediately transferred to the mating gestation
1992; See et al., 1993. Number of piglets born alive units. During lactation the animals were either fed
per litter for Hampshire sows has been reported to according to a Swedish standard level, e.g., 8 kg day
vary from about 7.4 Rico, 1988 to 9.4 piglets Bass 12 MJ kg for a sow with 10 piglets Simonsson,
et al., 1992. To our knowledge, no study on fertility 1994, or fed ad libitum. During gestation the sows
traits such as WSI, remating rate, farrowing rate and were fed 2 to 2.5 kg feed day. The reasons for
age at first farrowing for Hampshire sows has been culling the sows were in most cases due to low
published. breeding value or poor conformation. In all herds, a
The objective of the present study was to re- number of crossbred litters about 10 were also
trospectively analyse the variation in reproductive produced by crossing Hampshire sows with York-
performance of purebred Hampshire sows with re- shire or Landrace boars. The crossbred litters were
spect to parity influence and seasonal variation. The excluded from the statistical analyses, but results
effects of lactation length and WSI on subsequent from crossbred matings were included when analys-
fertility were also analysed. ing farrowing rate and remating rate.
2.2. Data analyses
2. Materials and methods
