Doctoral Dissertations

Date of Award

6-1974

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Animal Science

Major Professor

Sam L. Hansard

Committee Members

J.A. Corrick Jr., J.K. Bletner, L.H. Keller, F.B. Masincupp

Abstract

Data from 24 gilts starting their second trimester of gestation were used to evaluate reproductive performance of dam, maternal influence on baby pig composition and postnatal growth of progeny when maternal dam was limit-fed a standardized 16.0% protein diet during the last two-thirds of gestation and during lactation for three successive reproductive cycles. Gravid gilts (Sows) were maintained on concrete in open-fronted houses during the gestation period and individually fed 1.36 kg daily of a corn-soybean meal diet (C-SBM) formulated to provide 225.0 g protein and 4.6 Meal digestible energy intake. Menhaden fish meal replaced 2.0% of meat and bone scrap in a second corn-soybean meal diet supplemented with 120.0 mg dl-alpha-tocopherol and 1200.0 mg choline chloride/kg diet (Vit E-Chol). Sow lactation feed intake was limited to 1.36 kg plus 0.45 kg/pig nursing. Chemical composition of two neonatal pigs per litter was used to assess maternal dietary influence throughout successive gestations.

Confinement limited-feeding during the last two-thirds of gestation, supported increased maternal weight gains for the first two pregnancies (14.6 and 21.1 kg), but an extremely low gain (1.6 kg) was made during the last gestation (winter). Sows were in a negative weight balance for the controlled feeding periods of the last two reproductive cycles. Vit E-Chol sows nearly maintained body weight for the second reproductive cycle (summer) by higher gestation gain (P < .10) and smaller lactation weight loss.

Reduced maternal backfat thickness during third trimester of winter gestation one, and last two-thirds of the third gestation, accompanied by weight gains (first farrowing), suggest daily feed intake level was not sufficient to maintain maternal condition and products of gestation, simultaneously. Increased adipose tissue deposition in the second fat layer, during summer gestation, could indicate adequate energy for continued maternal growth. Lactation caused a further decrease in condition. Low sow weights at end of the third lactation were further evidence daily feed intake was inadequate for maternal growth through three successive reproductive cycles.

Fifty percent of the gilts started on each diet remained after three reproductive cycles (52 total farrowings). Failure to conceive at first post-weaning estrus caused removal of more Vit E-Chol sows. Higher incidence of hypogalactia was evident in C-SBM sows and apparent malnutrition during the last gestation caused abortion.

Increased number of total and live pigs farrowed per litter at successive gestations, indicated that ovulation and embryo survival were apparently not affected by feeding regime. Third farrowing birth weights were reduced. Vit E-Chol sows farrowed 1.2 more pigs per litter at third farrowing, but average birth weight was significantly (P > .05) less. Through three reproductive cycles, birth weights were significantly correlated with limited-feeding gestation gains (r = 0.42, P < .01) and condition changes (r = 0.40, P < .01).

Three-week litter performance increased in favor of Vit E-Chol pigs with successive lactations, except third lactation average pig weight and gain were lower (P > .05). Fetal priority over extrauterine maternal anabolism may have limited labile protein store of Vit E-Chol sows for subsequent milk production. Pre-weaning pig growth increased through the three lactations and more pigs were weaned per litter when creep diets included vitamin E. Higher creep feed consumption, per kilogram pig gain, indicated lower milking ability for third lactation sows.

Whole body gross energy and protein levels declined in succeeding farrowings with significantly (P < .01) lower levels in Vit E-Chol pigs at last farrowing. Over the three farrowings, Vit E-Chol carcass protein and moisture were significantly and negatively correlated (r = -.37, P < .01). There were no significant differences among neonatal pig liver chemical components, but percent hepatic fat in C-SM pigs was higher. It was significantly (P < .10) higher on dry matter basis at first farrowing. Average liver fat declined (2.30 to 1.04%) over the three farrowings.

Gestation mineral levels fed appeared to meet needs for fetal growth as there were no clinical symptoms of mineral deficiency at birth. Neonatal pig plasma mineral concentrations generally did not reflect trends for liver and whole carcass mineral concentrations. Tissue minerals studied tended to be lower in Vit E-Chol pigs than C-SBM pigs and concentrations were lowest at last farrowing.

Season and diet were associated with suboptimum sow reproductive performance and dietary intake levels proved inadequate to maintain the sow through three successive reproductive cycles. The 225.0 g protein/ day during gestation appeared to be sufficient for fetal development and growth, but pigs gestated by Vit E-Chol sows were less responsive, for some undetermined reason, in terras of their chemical and mineral composition levels. Progeny growth, however, did not appear to be permanently curtailed by gestation diets or level of lactation feeding.

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