The effect of condition at service and plane of nutrition in early pregnancy in the sow 1. Uterine and extra-uterine changes

Abstract

SUMMARYTwelve sows (F) were fed 7·3 kg/day and twelve (T) 3·7 kg/day of a 16% crude protein (CP) diet for the last 5 weeks of an 8-week lactation, so that at the subsequent service F sows were heavier (16%) and in better condition.From service to slaughter 70 days later, sows received either 3·7 kg/day (H) or 1·8 kg/day (L) of a 15% CP diet, giving four treatment combinations; FH, FL, TH and TL.In pregnancy H sows gained more weight than L sows and, on the low plane, F sows gained more weight than T sows. Ovulation rate as measured by corpora lutea count at slaughter was higher for TH than TL sows and for FL sows than FH sows. A combination of low ovulation rate and high mortality rate gave fewer foetuses (10·0) in the TL sows than in sows on the other treatments (13·5). Similarly mean foetal weight and thus foetal litter weight was least in TL sows. Foetal membranes, uterine fluids and uterine wall were lighter at slaughter in T sows than F sows and lighter in L sows than H sows, those of TL sows being appreciably the lightest.The results indicate that when the sow is in poor condition at service, body reserves being depleted, the uterus and its contents become more vulnerable to adverse pregnancy nutrition.

Thin sows: 1. Observations on the fecundity of sows when underfed for several parities

“…However, sows on the lowest plane of Elsley et al (1969) received more protein and energy than did the thin sows here. Some workers have reported an effect of body condition at mating (Hardy & Lodge, 1969;Pike & Boaz, 1972), and of the amount of feed given during the remating period on ovulation rate (Brooks & Cole, 1972a, b), and of the amount of feed during early pregnancy on embryo survival (Pike & Boaz, 1972). These would all tend to produce smaller litters, even though MacLean (1968) noted that litter sizes in herds with a thin sow problem ' appeared normal'.…”

Nutritional strategies to optimize reproductionin pigs

“…However, their results were not supported by a number of other reports, e.g. Hitchcock er at (1971), Pike & Boaz (1972), King et al (1982), Reese er al. (1982, King &Williams (1984a, b), andH ughes et al (1984).…”

Studies in sow reproduction. 3. The effect of nutrition between weaning and remating on the reproductive performance of multiparous sows

“…In two studies the ovulation rate of sows was found to be correlated with body condition and with weight loss during lactation (Heap, Lodge and Lamming, 1967;Hardy and Lodge, 1969). In other studies no such relationship was established (Brooks, 1970;Pike and Boaz, 1972). The inability to establish a relationship does not preclude the possibility that body weight and/or condition are implicated in reproductive performance but merely indicates that under the conditions imposed they were not a limiting factor.…”