title: The importance of a high feed intake during lactation of primiparous sows nursing large litters.
abstract: The objective of this study was to investigate whether nursing a large number of piglets has negative effects on lactation and postweaning performance of primiparous sows and whether a greater lactation feed intake can prevent possible negative effects. Data were recorded on 268 ad libitum-fed sows of three genotypes (G1, G2, and G3) in an experiment where litter size was standardized to 8, 11, or 14 piglets during a 4-wk lactation. Compared to G1 and G2, G3 sows were heavier (P < 0.05) and leaner (P < 0.05) at weaning of their litters, lost similar amounts of BW and backfat, and their piglets grew faster (P < 0.05). Compared to G1, feed intake during lactation was higher for G3 sows (P < 0.05), and their risk of a prolonged weaning-to-estrus interval was lower (P < 0.01). Daily feed intake by sows was not affected by litter size in G1 and G3, but it was quadratically affected in G2 (P < 0.05), with a maximum at 10.8 piglets. Backfat loss of the sows increased linearly with litter size (P < 0.05) in G1 and G3. In G2, backfat loss increased only at litter sizes > 9.8 piglets (P < 0.01). Body weight loss of the sow and litter weight gain increased linearly with litter size (P < 0.001). Per extra piglet nursed, sows had a 23% (P < 0.01) higher probability of a prolonged weaning-to-estrus interval. A higher daily feed intake during lactation reduced tissue loss of the sow, increased litter weight gain (P < 0.01), and reduced the probability of a prolonged weaning-to-estrus interval (by 42% per extra kilogram; P < 0.01). Sows with a lower daily body weight loss during first lactation had a larger second litter (1.28 piglets/kg; P < 0.01), and their probability of a prolonged weaning-to-estrus interval was reduced by 61% per kilogram (P < 0.001). With increasing litter size, it is therefore recommended to reduce body weight loss during lactation by stimulating daily feed intake and by genetic selection.
authors.affiliation: Animal Breeding and Genetics Group, Wageningen Institute of Animal Sciences, Wageningen University, 6700 AH Wageningen, The Netherlands.
authors.forename: J J
authors.initials: JJ
authors.lastname: Eissen
authors.forename: E J
authors.initials: EJ
authors.lastname: Apeldoorn
authors.forename: E
authors.initials: E
authors.lastname: Kanis
authors.forename: M W A
authors.initials: MW
authors.lastname: Verstegen
authors.forename: K H
authors.initials: KH
authors.lastname: de Greef
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D000833:Animals, Suckling / Q000254:growth & development; D001824:Body Constitution; D002149:Energy Intake / Q000502:physiology*; D004971:Estrus / Q000502:physiology; D005260:Female; D005838:Genotype; D007774:Lactation / Q000502:physiology*; D008098:Litter Size / Q000502:physiology*; D010298:Parity; D011897:Random Allocation; D013552:Swine / Q000235:genetics / Q000502:physiology*; D013997:Time Factors; D014886:Weaning; D015431:Weight Loss