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The present study was designed to determine the interrelationships between sex, weaning age, and weaning weight on subsequent growth performance. Ninety-six Large White × Landrace pigs were used in a 2 × 2 × 2 factorial experiment with the respective factors being: age at weaning (14 or 28 days), weight at weaning (heavy or light), and sex (boar or gilt). Eighty pigs were offered a high quality pelleted weaner diet ad libitum while the remaining 16 pigs (2 pigs from each treatment group) were removed from the sow and fasted for 24 h before being euthanased for determination of gut histology and enzymology. The remaining pigs were weaned into individual pens and given an ad libitum diet containing 15.5 MJ DE/kg and 0.95 g available lysine/MJ DE. On Day 6 and 13 after weaning, 2 pigs from each group at each time had their feed removed and, 24 h later, were euthanased. From 3 weeks post-weaning, the remaining pigs were group-penned with contemporary pigs and fed commercial rations until slaughter at 23 weeks of age. In the first week after weaning, the heavy pigs and those weaned at 28 days ate more feed and grew faster, and gilts ate more and grew faster than boars over the same time. Pigs that were heavier at weaning were also heavier at every subsequent age. At slaughter, heavy boars weighed more than heavy gilts (110.5 v. 103.7 kg, P = 0.027), whereas this was not the case for light boars and gilts (94.1 v. 94.4 kg, P = 0.96). Whereas there were no effects of sex or weight at weaning on P2 backfat depth, pigs weaned at 14 days had more backfat at 23 weeks than pigs weaned at 28 days (13.1 v. 10.9 mm, P = 0.009). In conclusion, these data clearly indicate that the greatest determinants of immediate post-weaning performance under the present conditions were the age and weight of the pigs at weaning. However, the key determinant of lifetime growth rate appeared to be weight of pigs at weaning or, by inference, birth. Although age at weaning had no effect on lifetime g

The present study was designed to determine the interrelationships between sex, weaning age, and weaning weight on aspects of physiological and gastrointestinal development in pigs. Forty-eight Large White x Landrace pigs were used in a factorial arrangement with the respective factors being: age at weaning (14 or 28 days), weight at weaning (heavy or light), sex (boar or gilt), and time after weaning (1, 7, and 14 days). At weaning, 48 pigs were removed from the sow; 16 pigs were then fasted for 24 h before euthanasia for determination of organ weights, gut histology, and enzymology, and 32 pigs were offered a high quality pelleted weaner diet ad libitum for subsequent assessment of organ weights, histology, and enzymology at 7 and 14 days after weaning. On Day 6 and 13 after weaning, 2 pigs from each group had their feed removed, and 24 h later were euthanased and similar measurements were taken. In general, the data highlighted the overall gastrointestinal underdevelopment of pigs weaned at 2 weeks of age and of pigs weaned light-for-age at either 2 or 4 weeks. Heavier body organs, gastrointestinal organs, and accessory digestive organs observed after weaning, except for the spleen, presumably reflected the increase in substrates available for cellular growth as feed intake increased after weaning, and the development of organs required to process this feed. Interestingly, the relative weights (% of liveweight) of the stomach and small intestine and, to a lesser extent, the caecum and colon, were greater in the light, 14-day-old weaned pigs, but these differences diminished with increasing time after weaning. Consistent effects due to age, weight, and sex were not observed for villous height and crypt depth, or for the specific activities of the brush-border and pancreatic enzymes measured. However, increases (P < 0.001) in the activities of maltase (P < 0.001), glucoamylase (P < 0.001), and sucrase (P = 0.020) (all expressed per gram of mucosa), and that of tryp

Digestive capacity of early-weaned pigs may be insufficient to fully digest many ingredients currently used in weaner diets. Ihe aim of this experiment was to determine whether an exogenous enzyme preparation with broad carbohydrase activity could benefit pigs that developmentally might be immature at weaning, especially with regard to gastrointestinal development. Eighty Large White x Landrace pigs were used in a 2 × 2 × 2 × 2 factorial experiment with the factors being: weaning age (14 or 24 days), weaning weight (heavy or light), sex (boar or gilt), and dietary Biofeed Plus CT (0 or 500 μg/g), which contained fungal xylanases, pentosanases, and β-glucanases. Pigs were housed individually and given a wheat-based (550 g/kg) diet containing 15.0 MJ DE and 15.9 g lysine/kg on an ad libitum basis for 21 days. The diet also contained 50 g/kg of soybean meal and 50 g/kg of lupin (Lupinus angustifolius) kernels. The liveweights of heavy (H) pigs weaned at 24 or 14 days and light pigs (L) weaned at 24 or 14 days were 7.9 and 5.3 and 5.2 and 3.9 kg, respectively. Pigs weaned at 14 days grew slower (157 v. 345 g/day) than those weaned at 24 days, although there was a suggestion of an interaction between age and weight at weaning (P = 0.081). Thus, H and L pigs weaned at 14 days grew at 148 and 166 g/day, whereas H and L pigs weaned at 24 days grew at 374 and 315 g/day, respectively. Although there was no main effect of enzymes on daily gain (248 v. 254 g/day, P = 0.80), feed intake (278 v. 284 g/day, P = 0.79), or feed conversion ratio (1.19 v. 1.25, P = 0.35), there were interactions with weaning age on daily gain (P = 0.050) and feed intake (P = 0.060). Pigs weaned at 14 days grew slower (176 v. 138 g/day) and ate less (206 v. 174 g/day), whereas pigs weaned at 24 days grew faster (321 v. 369 g/day) and ate more (351 v. 394 g/day), when supplemented with enzymes. During the third week after weaning there were interactions between dietary enzymes and sex (P = 0.060) and di

Seventy 14-day-old male pigs that were either heavy (6.0 kg) or light (3.6 kg) for age were weaned into individual pens and fed 1 of 7 diets containing 9.2-21.0 g lysine/kg feed in a study designed to determine the effect of dietary lysine and weight on lysine requirements of pigs. Five pigs from each weight group were used to determine initial body composition. When pigs reached 10 kg they were slaughtered and empty body composition was analysed to determine protein tissue accretion rates. Protein deposition rate was not affected by weight at weaning but increased with dietary lysine content before reaching a plateau. The relationship between protein deposition (PD, g/day) and dietary lysine (L, g/kg) was described by 3 models. The rectilinear model, which had a linear ascending phase (PD = 4.84 + 1.948L, R2 = 0.935, P = 0.002) and a horizontal component representing maximum protein deposition rate of 32.3 g/day, revealed that maximum protein deposition occurred at 14.1 g lysine/kg. The quadratic function (PD = - 2.74 + 3.74L - 0.099L2, R2 = 0.916, P = 0.003) provided an estimate of the lysine requirement of 14.9 g lysine/kg occurring at a point where PD reached 95% of the maximum protein deposition rate (32.5 g/day). Use of an asymptotic model (PD = 32.60 - 186 x 0.727L, R2 = 0.919, P = 0.003) provided an estimate of 14.9 g lysine/kg occurring at a point where PD reached 95% of the maximum protein deposition rate (32.6 g/day). These data indicate that early weaned pigs should be fed a highly digestible diet containing 14-15 g lysine/kg to maximise protein deposition.

Pigs are commonly wean~d at 23-27 days of age. By weaning earlier and providing pigs with high quality diets, it may be possible to increase growth performance up to slaughter. However, digestive capacity of early weaned pigs may be insufficient to fully digest many ingredients currently used in weaner diets. The aim of this experiment was to determine whether an exogenous enzyme preparation with broad carbohydrase activity could benefit pigs that were possibly developmentally immature at weaning.

While pigs are commonly weaned at 23-27 days of age, sow milk production peaks at 10-14 days of lactation after which it limits growth. By weaning earlier and providing pigs with a suitable diet, it may be possible to increase growth of the young pig. However, it is possible that the digestive function of early-weaned pigs may be immature and incapable of digesting many feedstuffs. The present study was designed to examine some of the factors that might influence small intestinal function in the weaned pig.

Pigs are commonly weaned at 23-27 days of age. However, sow milk production peaks at 10-14 days of lactation after which it is only sufficient for pigs to attain about 50% of their growth potential (Dunshea et al., 1995). By weaning earlier and providing pigs with a suitable diet, it may be possible to capitalize on their potential for rapid growth. The present study was designed to determine the interrelationships between sex, weaning age and weaning weight on subsequent growth performance.

Many pig producers are moving towards early weaning in an effort to minimise disease transfer from sow to piglet. However, it is possible that the digestive function of early-weaned pigs may be immature and incapable of digesting many feedstuffs. The present study was designed to examine some of the factors that might influence pancreatic enzymic function in the weaned pig.

This experiment was designed to investigate the interactions between weaning weight and dietary lysine in pigs weaned at 14 days.

The present study was conducted to determine the interrelationships between age, sex and weight at weaning, on subsequent growth performance of pigs.