Records of 176 Hampshire pigs, consisting of 118 barrows and 58 gilts, were used in this study. The least squares method was applied to estimate the effect of rate of gain during four periods of growth (birth to 50 pounds, 50 to 100 pounds, 100 to 150 pounds, and 150 to 200 pounds) on carcass characteristics. The results were expressed as partial regression coefficients in terms of square inches or inches per pound for deviation in growth rate. The loin eye area and the average back fat thickness had a consistent, but not statistically significant association with the live weight groupings as arbitrarily designation. The carcass length was inconsistently and statistically nonsignificantly related to the live weight. Sex of the animal did effect the carcass in that gilts had leaner carcasses than barrows as shown by larger loin eye areas and thinner back fat. When the average daily gain increased one pound during 100 to 150 pound growing period, the loin eye area was 0.40 square inches larger at a slaughter weight of 200 pounds. When the average daily gain increased one pound during the suckling period, the average back fat was 0.25 inches thinner at 200 pounds. As the daily gain increased one pound during the second growing period, the average back fat was 0.15 inches thicker in the finished pigs. The growth rate had a statistically nonsignificant effect on the carcass length during any period of growth. The growth rate during period other than those shown had no effect on the carcass characteristics measured in this study. / Master of Science

Four trials were conducted to examine the pattern of creep feed consumption of nursing pigs and the effect of creep feeding - from 10 d to weaning at 28 d - a 20% crude protein corn-soybean meal and dried whole whey diet (REG, 9 litters) containing 1.0% chromic oxide for detection of creep feed consumption, or the same diet with 2.7% ovalbumin (OVA) added as a dietary antigen (14 litters), or no creep feed (CON, 11 litters) on the immune response, scouring index, and subsequent performance of weanling pigs. All nursing pigs were denied access to sow feeders but had water ad libitum. At weaning, pigs were fed either a 20% corn-soybean meal diet, with or without 2.7% OVA. Creep-fed litters began eating at 11 d of age and disappearance of creep feed increased linearly until weaning (P < .01). However, the presence of chromic oxide in the feces was not consistently observed in the same pigs thus suggesting that creep consumption by individual pigs was quite variable. Average feed consumption based on total creep disappearance per litter was 13 to 194 g/pig preweaning. Daily gain and body weight of nursing pigs was similar during the first 4 wk. Pigs from larger litters had lower birth weights (P < .05), lower 4 wk body weights (P < .09) and daily gains (P < .09), as well as less feed disappearance per pig (P < .02). Pigs fed the OVA diet had higher (P > .001) antibody titers to OVA than did pigs receiving the REG or CON treatments at 14, 21, or 28 d of age. At 56 d and 63 d, all pigs given an OVA injection (at 49 d 1 ml of 3 mg/ml OVA) responded, (P < . 001) with the lowest titers for REG pigs, intermediate for CON pigs, and the highest for OVA pigs during the nursery phase. Scouring began 4 to 5 d postweaning with creep-fed pigs scouring slightly more. Feed consumption, although not statistically different, was higher (P = .18) during the first week postweaning for CON pigs and was consistent throughout the study, but daily gains and feed efficiency were similar. In summary, creep feed disappearance begins increases linearly until weaning with no effect on cumulative daily gain or body weight. While larger litters consume more total feed, smaller litters consume more feed per pig. Creep feeding had some effect on antibody response and scouring our results suggest little apparent effect on postweaning performance. / Master of Science

Pigs can consume a wide range of feeds to meet their nutritional needs and there is a renewed interest in the use of cheaper nutrient resources for animal feeding. Forages have been proved to be a substantial source of nutrients for pigs, however, the bulk of the existing work has focused on sows and grower-finisher pigs above 50 kg. This study was conducted during May-June 2009 at the Agricultural Research Council (Irene, Pretoria) to determine the voluntary forage intake and nutrient digestibility in growing pigs fed a mixed diet (concentrate + Kikuyu grass). Twenty five 8 weeks old Large White x Landrace crossbred pigs (27 ± 3.8 kg) were blocked by weight into 5 groups of 5 pigs each. One of 5 treatments (A, B, C, D and E), corresponding to 100, 90, 80, 70 and 80 % of a basal concentrate ration, respectively, was randomly assigned to a pig within each block. Indoor treatments were either fed the concentrate only (A) or also received freshly cut Kikuyu grass (Pennissetum clandestinum) ad libitum (B, C and D). Only treatment E animals were housed outdoors in Kikuyu grass paddocks while all other treatments were housed indoors. Forage intake was recorded daily and also estimated using a pair of n-alkanes as markers. Nutrient and diet digestibility were calculated using acid-insoluble ash (AIA) and dotriacontane (C32) as markers. The results showed that the concentrate intake (CI) in treatments A, B and C was significantly different from treatments C and E (P < 0.05) and there was positive correlation between the concentrate level and its intake (P < 0.01). The recorded intake of Kikuyu grass (RKI) and the animal’s average daily gain (ADG) were similar between treatments (P > 0.05). The estimated (EKI) and recorded (RKI) Kikuyu grass intakes were not influenced by CI or the level of concentrate allowance (CL) and RKI was higher (P < 0.05) than EKI. Digestibility estimates with AIA were higher than C32 Keywords: Dotriacontane; Kikuyu; growth performance; forage; monogastrics estimates (P < 0.05). It was concluded that Kikuyu grass intake was not affected by the reduction of the concentrate level allowance. It was proposed that forage intake in a mixed diet (forage + concentrate) was more dependant on its own characteristics than the concentrate’s nutritional value. / Agriculture, Animal Health and Human Ecology / M. Sc. (Agriculture)

The impact of within-litter weight variation on the productivity of pig enterprises is poorly understood. The objective of the study was to determine the effect of within-litter birth weight variation on litter performance at three weeks of age and at weaning. The study was conducted using records from 1 788 litters, collected between January 1998 and September 2010, from a pig herd at the Agricultural Research Council (ARC), Irene. The records consisted of piglet identity, breed of sow, breed of boar, parity number, date of farrowing, number of piglets born alive (NBA), individual piglet weight at birth, three weeks and at weaning. From these records, mean birth weight (MBWT), litter weight at birth (TBWT), within-litter birth weight coefficient of variation (CVB), minimum birth weight (MinB) and maximum birth weight (MaxB) were calculated. Mean weight at three weeks (MWTT), litter weight at three weeks (LWTT), within-litter weight coefficient of variation at three weeks (CVT), percent survival to three weeks (SURVT), mean litter weaning weight (MWWT), litter weight at weaning (LWWT), within-litter weaning weight coefficient of variation (CVW) and percent survival at weaning (SURVW) were computed as derivatives. The factors affecting CVB were analysed using the General Linear Model procedures (SAS, 2008). For the relationships between CVB and litter performance at three weeks and weaning, PROC STEPWISE was used. The PROC REG (SAS, 2008) was then used to test whether the relationships between CVB and CVT, SURVT, MWTT, LWTT, CVW, SURVW, MWWT, LWWT and LWWT. Multiparous sows farrowed litters with higher (P<0.05) CVB than gilts. The litter weight (TBWT) and NBA, fitted as covariates, also affected (P<0.05) CVB. The correlation between CVB and NBA was 0.30. The CVB had a linear relationship (P<0.05) with SURVT (SURVT = 83.21 - 0.20 CVB), CVT (CVT = 16.71 + 0.50 CVB), SURV (SURW = 87.9 – 0.04CVB) and CVW (CVW= 15.8 + 0.5CVB). An increase of CVT with CVB depended on parity (P<0.05). The rate of increase of CVT with CVB was highest in Parity 1 (b=0.41) followed by Parity 2 (b=0.36) then middle aged (Parity 3-5) sows (b=0.32). The CVB had no effect on MWTT, LWTT, MWWT and LWWT (P>0.05). The CVB was shown to be an important determinant of SURVT and SURVW. A uniform litter at birth is likely to lead to a homogenous litter at three weeks and weaning, thereby reducing costs of production. Pig producers should, therefore aim at producing homogenous litters at birth. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

Addendum pasted onto front end-paper. / Bibliography: leaves 176-216. / x, 216 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The aim of this project is to determine why LR3IGF-1 has such divergent effects in two different species. The study investigates the endocrine regulation of IGF-I and IGF binding protein-3 (IGFBP-3) in the pig and determines the effects of IGF-I and LR3IGF-I treatment on porcine IGF-I and IGFBP-3 expression at the gene and protein level. / Thesis (Ph.D.)--University of Adelaide, Dept. of Obstetrics and Gynaecology, 1997

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 150-177). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 150-177). Also available on the Internet.

Pigs can consume a wide range of feeds to meet their nutritional needs and there is a renewed interest in the use of cheaper nutrient resources for animal feeding. Forages have been proved to be a substantial source of nutrients for pigs, however, the bulk of the existing work has focused on sows and grower-finisher pigs above 50 kg. This study was conducted during May-June 2009 at the Agricultural Research Council (Irene, Pretoria) to determine the voluntary forage intake and nutrient digestibility in growing pigs fed a mixed diet (concentrate + Kikuyu grass). Twenty five 8 weeks old Large White x Landrace crossbred pigs (27 ± 3.8 kg) were blocked by weight into 5 groups of 5 pigs each. One of 5 treatments (A, B, C, D and E), corresponding to 100, 90, 80, 70 and 80 % of a basal concentrate ration, respectively, was randomly assigned to a pig within each block. Indoor treatments were either fed the concentrate only (A) or also received freshly cut Kikuyu grass (Pennissetum clandestinum) ad libitum (B, C and D). Only treatment E animals were housed outdoors in Kikuyu grass paddocks while all other treatments were housed indoors. Forage intake was recorded daily and also estimated using a pair of n-alkanes as markers. Nutrient and diet digestibility were calculated using acid-insoluble ash (AIA) and dotriacontane (C32) as markers. The results showed that the concentrate intake (CI) in treatments A, B and C was significantly different from treatments C and E (P < 0.05) and there was positive correlation between the concentrate level and its intake (P < 0.01). The recorded intake of Kikuyu grass (RKI) and the animal’s average daily gain (ADG) were similar between treatments (P > 0.05). The estimated (EKI) and recorded (RKI) Kikuyu grass intakes were not influenced by CI or the level of concentrate allowance (CL) and RKI was higher (P < 0.05) than EKI. Digestibility estimates with AIA were higher than C32 Keywords: Dotriacontane; Kikuyu; growth performance; forage; monogastrics estimates (P < 0.05). It was concluded that Kikuyu grass intake was not affected by the reduction of the concentrate level allowance. It was proposed that forage intake in a mixed diet (forage + concentrate) was more dependant on its own characteristics than the concentrate’s nutritional value. / Agriculture, Animal Health and Human Ecology / M. Sc. (Agriculture)

Thirteen trials (n=930) were conducted to investigate the supplementation of weanling pigs with high levels of Zn and to compare the availability of Zn from several Zn sources for weanling pigs. In the first four trials, supplementing Zn by injecting Zn acetate either i.m. or i.p. at various times near weaning did not improve postweaning growth performance compared with pigs that were not injected. Additionally, stressing pigs by regrouping and then injecting Zn acetate did not improve growth performance. Serum Zn concentrations were increased in all of the trials by the injection of Zn. In the next five trials, feeding 3,000, 2,000 or 1,000 mg Zn/kg of diet from ZnSO₄, Zn-lysine or Zn-methionine did not improve growth performance immediately after weaning compared with pigs fed diets with 105 mg Zn/kg of diet. Feeding 3,000 mg Zn/kg of diet as ZnO (P < .05) improved growth performance above that of pigs fed 3,000 mg Zn/kg of diet from the other sources, but did not improve growth performance compared to controls. Lower tissue Zn concentrations suggested a lower availability of Zn from ZnO compared with ZnSO₄, Zn-lysine and Zn-methionine. There was little difference in Zn availability among the other sources. In the next three trials, feeding diets with different levels of lysine had little influence on the availability of Zn from Zn-lysine compared to ZnSO₄. Results indicate that Zn from Zn-lysine is not absorbed in conjunction with the lysine component of the complex. Additionally, there were no differences in the availability of Zn from ZnSO₄ compared to Zn-lysine. In the last trial, Zn from ZnO was less available (P < .05) to Zn deficient pigs than ZnSO₄, Zn-lysine or Zn-methionine when rib bone Zn concentration was used as an indicator of Zn availability. In summary, supplementing weanling pigs with high levels of Zn immediately before or after weaning does not appear to improve growth performance. Furthermore, Zn from ZnO is less available to weanling pigs than Zn from ZnSO₄, Zn-lysine or Zn-methionine. / Ph. D.

Thesis (M. Tech. (Agirculture)) -- Central University of Technology, Free State, 2015