Blood Volume Changes During Pregnancy and Lactation of Sows

Abstract

Plasma volume and haematocrit were measured at approximately 20 days intervals in 3 gilts (sows in their first pregnancy and lactation) throughout pregnancy and in 2 of these gilts during lactation. Measurements were made at the beginning and end of pregnancy in a further 9 sows and also at mid-pregnancy in 4 of these latter sows.In the gilts PV declined during the first 40 days and then increased until parturition. In lactation the PV continued to rise during the first 14 days and then decreased steadily until weaning. Calculated RCV increased linearly during pregnancy and fell inmediately after parturition.The results obtained from the sows again showed only a slght rise in PV and RCY until day 70 and then a sharp rise until parturition. There was no relationship between the increase in PV and the weight of the litter born.

Changes of serum and blood volumes during gestation and lactation in multiparous sows

“…In this last case, the observatrons are difflrcult to compare because the results were collected under field conditionJon different groups of animals at each of the studied periods. The increase of serum volume at the end of gestation, which was approximately 25%o rn the present Jxperiment, was lower than the 300/o increase reported for gifts by Anderson et al (1970) and the 50%o increase oUreru"O in sows by Jezkova et al' (1977). The difference between the results reported by Anderson et al (1970) and ours might be related to a greater precision in the present experiment because more animals were used.…”

“…Theywere Jezkova et al lgli),an increase of at least 30% rrthe plasma kept in individual cages throughout the trial and fed 2.5 kg volume was observed during the gestation, the augmenta-of a gestation diet, described previously (Matte-et al 1994 pr"gnurr"!.^During lactation, a furthir increase of plasma P. Plasma volume was determined for each animal at f,tve volume was observed in gilti; a peak was reached bilween different times before and during gestation, using Evans days 14 and 2l and was followed by a return, at 42 d of lac-blue dye as an indicator. A blood sample was withdrawn by tation, to the level observed at the end of pregnancy jugularvenipuncture afterafastingperiodof atleast 8 h' A (Anderson et al 1970). Punctual measurements witnlimlted diJposable catheter (Angiocath, Deseret, Becton-Dickinson numbers of multiparous sows reported by Anderson et al and Co., Sandy, UT) was inserted in the cephalic vein ' Two (1970) confirmed the results observed with gilts.…”

“…In swine, on a limited number of Thirty-six sows were selected after their first parity. They gilts in = 3 in Anderson et al 1970) and sows (n = 2 in werematedattheirsecondpost-weaningoestrus. Theywere Jezkova et al lgli),an increase of at least 30% rrthe plasma kept in individual cages throughout the trial and fed 2.5 kg volume was observed during the gestation, the augmenta-of a gestation diet, described previously (Matte-et al 1994 pr"gnurr"!.^During lactation, a furthir increase of plasma P. Plasma volume was determined for each animal at f,tve volume was observed in gilti; a peak was reached bilween different times before and during gestation, using Evans days 14 and 2l and was followed by a return, at 42 d of lac-blue dye as an indicator.…”

“…There was no change (P > 0.05) in btood and serum-volumes between 4 wk pre-mating and I wk post-matlng' During gestation, blood and serum volumes increasei by approximat ely 2.5%, with most of this increase occurring between 1 1 and l4 wk ofpregnancy (p < 0.006 pr"gnurr"!.^During lactation, a furthir increase of plasma P. Plasma volume was determined for each animal at f,tve volume was observed in gilti; a peak was reached bilween different times before and during gestation, using Evans days 14 and 2l and was followed by a return, at 42 d of lac-blue dye as an indicator. A blood sample was withdrawn by tation, to the level observed at the end of pregnancy jugularvenipuncture afterafastingperiodof atleast 8 h' A (Anderson et al 1970 …”

Uterine blood flow in sows: effects of pregnancy stage and litter size

“…This change is partly explained by a faster heart rate of the mother, as shown in ewes [11,50], and by a redirection of blood flow to the uterus at the expense of other tissues and organs, like skin and carcass (ewe: Rosenfeld et al [50]; cow: Ferrell and Ford [20]; guinea pig: Peeters et al [39]). The increase in blood volume during pregnancy shown in pigs [2,36,51], and the greater uterine artery endothelial production of the potent vasodilatators, prostacyclin and nitric oxide, demonstrated in pregnant sheep [34], may also be involved.…”