Agriculture Reference
In-Depth Information
Table 17.1. Effects of feed intake (high vs. low
1
) during lactation on weaning-to-oestrus interval (WEI),
ovulation rate and embryo survival.
Ovulation rate
2
Embryo survival(%)
3
Reference
Weaning age
WEI (days)
High
Low
High
Low
High
Low
King and Williams (1984)
d32
7.6a
19.9b
14.4
13.5
70
72
Kirkwood
et al.
(1987)
d35
4.3a
5.8b
18.1
18.6
83a
68b
Kirkwood
et al.
(1990)
d28
6.0a
8.9b
17.6
17.7
83a
72b
Baidoo
et al.
(1992)
d28
5.9
7.5
16.2
16.7
85a
64b
Zak
et al.
(1997a) L:wk1-3
4
d28
3.7
5.6
19.9a
15.4b
88a
87
Zak
et al.
(1997a) L:wk4
d28
5.1
15.4b
64b
Zak
et al.
(1998)
d28
4.2a
6.3b
14.4
15.6
83
72
Quesnel and Prunier (1998)
d24
5.7
5.9
19.2
20.7
-
-
Van den Brand
et al.
(2000c)
d22
5.1
5.7
18.1a
16.4b
68
68
Terletski
et al.,
unpublished
5
d21
6.6
6.7
18.6a
16.7b
64
69
Vinsky
et al.
(2006)
6
d21
5.3
5.4
18.3
18.2
79a
68b
Foxcroft
et al.,
unpublished
d21
5.7
5.5
18.5
17.5
65a
78b
Patterson
et al.
(2011) L:wk3
d20
5.0
5.3
19.7
20.2
71
70
1
High ca. 80-90% of
ad libitum;
low ca. 40-60% of
ad libitum.
2
Number of ovulated oocytes per sow.
3
ab (
P
<0.05).
4
L:wk: Weeks of lactation in which feed intake treatment was applied.
5
High: control fed >190 kg farrow weight; low: restricted fed <170 kg farrow weight.
6
Number of female embryos lower in restrict sows.
a result of strong genetic selection for short weaning-to-oestrus intervals. As a result, the
effects of low feed intake during lactation on weaning-to-oestrus intervals have become
less pronounced over the years, but effects on litter size and pregnancy rate have become
more pronounced. Nevertheless, recent studies still report a relation between lactational
feed intake and subsequent weaning-to-first service interval (Yoder
et al.
, 2012; 2013)
in sows with a 19 day lactation; weaning-to-first service interval being predominantly
affected when drops in feed intake occurred during late lactation.
These effects of lactational feed intake on subsequent fertility parameters originate from
its effect on LH-release and initial follicle development. Quesnel
et al.
(1998) showed
that first litter sows that were fed at 50% of
ad libitum
intake had lower LH-pulsatility
before and after weaning and had smaller follicles at weaning and two days after weaning
as compared with
ad libitum
fed sows. On day 2 after weaning, the average number of
follicles larger than 4 mm was 6.8±2.7 for the restricted-fed sows and 12.2±1.3 for the
ad
libitum
-fed sows. Zak
et al.
(1997b) also demonstrated that not only follicle size, but also
follicle and oocyte quality were affected by feed restriction. At approximately 4 days after
weaning, a lower percentage of oocytes from restricted-fed sows were able to mature
in
vitro
and the follicular fluid of these oocytes resulted in a reduced number of matured
