Influence of feed restriction in primiparous lactating sows on body condition and metabolic parameters.
Twenty-four primiparous sows were allocated at farrowing to a high (H: 5.5-6 kg feed/day) or a low (L: 2.5-3 kg/day) level of feeding. Litters (8-10 piglets) were weaned at 28+/-2 days. Serial blood samples were collected 1 day before weaning (W-1), in the hours following weaning (W) and 1 day after (W + 1). L sows lost significantly more weight (38 versus 15 kg) and backfat (5.3 versus 2.3 mm) during lactation than H sows. On day W-1, L sows had higher mean concentrations of NEFA (P < 0.01) and GH (P < 0.1 ) and lower concentrations of insulin and IGF-I (P < 0.05) than H sows. Mean concentrations of glucose and cortisol did not differ between groups of sows. On day W + 1, these parameters were not different between treatments, except IGF-I concentrations which remained lower in L than in H sows (P < 0.05). We conclude that lactating primiparous sows alter secretion of metabolic hormones to favour mobilization of body reserves to support milk production. Low insulin and IGF-I may be involved in reduced ovarian activity at and after weaning, through LH-dependent and independent pathways.
Quesnel
H
H
Station de recherches porcines, Inra, Saint-Gilles, France. quesnel@st-gilles.rennes.inra.fr
Pasquier
A
A
Mounier
A M
AM
Louveau
I
I
Prunier
A
A
D000818:Animals; D001823:Body Composition; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D005508:Food Deprivation; D013006:Growth Hormone / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007774:Lactation; D008098:Litter Size; D010298:Parity; D013552:Swine / Q000502:physiology*
D005230:Fatty Acids, Nonesterified; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone