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The objective of the current study was to quantify loss of energy in feces, urine, heat, and milk, to evaluate feed efficiency and to evaluate optimal ratio of dietary CP to energy for lactating sows fed increasing dietary CP. A total of 72 sows were included in the experiment from day 2 after parturition until weaning at day 28. Sows were allocated to 6 dietary treatments formulated to be isocaloric (9.8 MJ NE/kg) and increasing standardized ileal digestible (SID) CP (11.8, 12.8, 13.4, 14.0, 14.7, and 15.6% SID CP). Sows were weighed and back fat scanned within 2 d after farrowing, at days 18 ± 3 and 28 ± 3. Litters were standardized to 14 piglets within 2 d after farrowing and weighed at day 1 or 2 and at days 11, 18, and 28 (within ± 3 d). Feed intake (feed supply minus residue) was registered, and milk, urine, and fecal samples were collected at days 4, 11, and 18 (within ± 3 d). Sow milk yield was estimated from litter gain and litter size, and sow heat production was calculated factorially. On days 4 and 18 (±3 d), sows were enriched with D2O (deuterated water) to estimate body protein and fat pool size. Overall, sow BW loss, back fat loss, fat and protein mobilization, litter size, and piglet performance were not affected by diets, except for sows fed treatment 5, which had lower ADFI and lower milk production, and a tendency to lower piglet ADG compared with the remaining treatment groups (P < 0.01, P = 0.03, P =0.08, respectively). Relative to GE intake, the energy excreted in urine increased from 3.3% to 5.3% (P < 0.001), whereas energy lost as heat increased numerically from 54.5% to 59.0% with increasing dietary CP. The feed efficiency as evaluated by NE corrected for body mobilization peaked when sows were fed at their requirement (treatment 2; 12.8% SID CP; P = 0.01), whereas the feed efficiency was 1% lower for treatment 1, whereas it was 3% to 6% lower for treatments 3 through 6. In conclusion, energy loss in urine and likely also energy lost as heat increase if the dietary protein to energy ratio is unbalanced, and evaluating feed efficiency of lactating sows by correcting for body mobilization seems to be a promising approach to improve sow feeding in the future. [ABSTRACT FROM AUTHOR]

Diets fed to nonruminant animals are composed mainly of feed ingredients of plant origin. A variety of antinutritional factors such as phytin, nonstarch polysaccharides, and protease inhibitors may be present in these feed ingredients, which could limit nutrients that may be utilized by animals fed such diets. The primary nutrient utilization-limiting effect of phytin arises from the binding of 6 phosphate groups, thus making the P unavailable to the animal. The negative charges allow for formation of insoluble phytin-metal complexes with many divalent cations. Furthermore, phytin and protein can form binary complexes through electrostatic links of its charged phosphate groups with either the free amino group on AA on proteins or via formation of ternary complexes of phytin, Ca2+, and protein. The form and extent of de novo formation of binary and ternary complexes of phytin and protein are likely to be important variables that influence the effectiveness of nutrient hydrolysis in plant-based diets. Nonstarch polysacharides reduce effective energy and nutrient utilization by nonruminant animals because of a lack of the enzymes needed for breaking down the complex cell wall structure that encapsulate other nutrients. Enzymes are used in nonruminant animal production to promote growth and efficiency of nutrient utilization and reduce nutrient excretion. The enzymes used include those that target phytin and nonstarch polysaccharides. Phytase improves growth and enhances P utilization, but positive effects on other nutrients are not always observed. Nonstarch polysaccharide-hydrolyzing enzymes are less consistent in their effects on growth and nutrient utilization, although they show promise and it is imperative to closely match both types and amounts of nonstarch polysaccharides with appropriate enzyme for beneficial effects. When used together with phytase, nonstarch polysaccharide-hydrolyzing enzymes may increase the accessibility of phytase to phytin encapsulated in cell walls. The future of enzymes in nonruminant animal production is promising and will likely include an understanding of the role of enzyme supplementation in promoting health as well as how enzymes may modulate gene functions. This review is an attempt to summarize current thinking in this area, provide some clarity in nomenclature and mechanisms, and suggest opportunities for expanded exploitation of this unique biotechnology. [ABSTRACT FROM AUTHOR]

A total of 84 sows (PIC Line 1050) were blocked according to day of farrowing and parity and allotted in a 2 × 2 factorial arrangement of treatments with lactation feed intake (ad libitum vs. restricted) and creep feeding (no vs. yes) as factors. Sows fed for ad libiturn intake (ad libitum-fed) were allowed free access to a common lactation diet (3,503 kcal of ME/kg, 0.97% standardized ileal digestible Lys), and sows with restricted intake (restricted-fed) were fed 25% less than ad libitum-fed sows. A creep diet (3,495 ME/kg, 1.56% standardized ileal digestible Lys) with 1.0% chromic oxide was offered to creep-fed pigs from d 3 to 21. Fecal samples from creep-fed pigs were taken with sterile swabs on d 7, 14, and 21, and color was assessed to categorize pigs as eaters or non-eaters. There were no interactions (P > 0.15) between lactation feed intake and creep feeding. Ad libitum-fed sows had greater (P < 0.01) total feed intake and ADFI (99.4, 4.9 kg) than restricted-fed sows (67.9, 3.6 kg). Ad libitum-fed sows had reduced BW loss (-15 vs. -24 kg; P < 0.01), improved total (46.7 vs. 43.0 kg; P < 0.04) and daily (2.56 vs. 2.36 kg; P < 0.04) BW gains of litters, and increased (90 vs. 71%; P < 0.03) percentage of sows returning to estrus by d 14 compared with restricted-fed sows. Creep feeding for 18 d did not affect (P > 0.34) sow BW and backfat loss but increased days to estrus (5.4 vs. 4.9 d; P < 0.03). Creep feeding had no (P> 0.16) effect on preweaning growth performance. Postweaning performance of creep-fed and non-creep-fed pigs was similar (P > 0.86). When individual pigs were categorized on the basis of creep feed consumption category, eaters had greater (P < 0.05) ADG (393, 376, and 378 g) and total BW gains (11.0, 10.5, and 10.6 kg) than non-eaters or non-creep-fed pigs. In conclusion, creep feeding for 18 d did not affect preweaning and lactating sow performance. Low feed intake during lactation negatively affected sow and litter performance. Creating more creep-feed eaters during the lactation period may benefit postweaning performance. Therefore, dietary and nondietary factors that can enhance the proportion of eaters in litters should be investigated. [ABSTRACT FROM AUTHOR]

Water quality in the United States is threatened by contamination with nutrients, primarily nitrogen and phosphorus. Animal manure can be a valuable resource for farmers, providing nutrients, improving soil structure, and increasing vegetative cover to decrease erosion potential. At the same time, application of manure nutrients in excess of crop requirements can result in environmental contamination. Environmental concerns with P are primarily associated with pollution of surface water (streams, lakes, rivers). This pollution may be caused by runoff of P when application to land is in excess of crop requirements. Increased specialization and concentration of livestock and crop production has led to the net export of nutrients from major crop-producing areas of the country to areas with a high concentration of animal agriculture. Concentrated animal agriculture has been identified as a significant source of P contamination of surface water. Areas facing the dilemma of an economically important livestock industry concentrated in an environmentally sensitive area have few options. If agricultural practices continue as they have in the past, continued damage to water resources and a loss of fishing and recreational activity are inevitable. If agricultural productivity is decreased, however, the maintenance of a stable farm economy, a viable rural economy, and a reliable domestic food supply are seriously threatened. Decreasing the P content of manure through nutrition is a powerful, cost-effective approach to reducing P losses from livestock farms and will help farmers meet increasingly stringent environmental regulations. This paper reviews opportunities available to reduce the P content of livestock manure, including more accurate interpretation of the published P requirements of animals, improved diet formulation and group-feeding strategies to more precisely meet requirements, and approaches to improve availability of feed P for monogastric and ruminant species. [ABSTRACT FROM AUTHOR]

This study was conducted to determine the effect of reduced lactation length and supplemental milk replacer (MR) during high ambient temperatures. Thirty nine primiparous and 100 multiparous sows (PIC, Franklin, KY, C-22) were used in a 2 × 2 × 2 factorial arrangement of treatments. Treatments consisted of two lactation room temperatures (21°C [TN] and 32°C [HOT]), two lactation lengths (14 or 19 d), and two parity groups (primiparous, multiparous). Pigs were either: 1) sow-reared to 19 d or 2) sow-reared to 14 d, and then reared to 19 d with MR after sow removal. All sows were fed the same diet (1.07% lysine, 3,366 kcal of ME/kg). Sows were weighed and ultrasound for backfat thickness (BF) and longissimus muscle area (LMA) within 6 h after farrowing and at the time of sow removal (d 14 or 19). Pigs were individually weighed at weaning (d 19) and after a 47-d nursery period (d 66). Heat stress increased sow weight loss (-13.35 kg, P < 0.01) and decreased sow feed intake (4.63 kg/d, P < 0.01) during lactation compared with sows in TN (+4.5 kg and 7.5 kg/d, respectively). Early weaning (d 14) during heat stress decreased maternal weight loss (-10.1 vs. -16.6 kg, P < 0.01). Primiparous sows lost more BF in both environments (-2.60 vs. -1.56 mm, P < 0.05), and both parity groups lost more BF (-3.35 vs. -2.3 mm, P < 0.10) and LMA (-1.82 vs. -0.77 cm², P < 0.05) when lactating for 19 d in the HOT environment than those lactating for 14 d. Pigs nursing primiparous and multiparous sows in the HOT environment and provided MR had heavier individual 19-d weights (7.37 and 8.12 kg/ pig, respectively) than those nursing to 19 d (5.57 and 6.04 kg/pig, P < 0.01). Milk replacer decreased the difference normally observed in 19-d weights between primiparous and multiparous sow-reared pigs in TN. Pigs fed MR in both environments and nursing multiparous sows had improved weight gains in the nursery compared with pigs nursing sows to 19 d (428 vs. 406 g/d,... [ABSTRACT FROM AUTHOR]

This study was designed to test the degree of protein loss that may be sustained by lactating sows before milk biosynthesis and ovarian function will be impaired. First-parity Camborough × Canabrid sows were allocated to receive isocaloric diets (61 ± 2.0 MJ of ME/d) and one of three levels of protein intake in lactation: 1) 878 g of CP and 50 g of lysine/d (n = 8), 2) 647 g of CP and 35 g of lysine/d (n = 7), or 3) 491 g of CP and 24 g of lysine/d (n = 10). Every 5 d during a 23d lactation, sow live weight, backfat depth, and litter weight were recorded, and a preprandial blood sample was collected. Milk samples were collected on d 10 and 20 of lactation. Sows were slaughtered on the day of weaning, and liver and ovarian variables were measured. Lower dietary protein intakes elicited progressively larger live weight losses during lactation (-13, -17, and -28 ± 2.3 kg; P < 0.001), but similar and minimal backfat losses (-1.3 ± 0.29 mm). Approximately 7, 9, and 16% of the calculated body protein mass at parturition was mobilized by d 23. Lactation performance did not differ among treatments until d 20, at which time approximately 5, 6, and 12% of the calculated protein mass at parturition had been lost. The milk protein concentration on d 20 of lactation reflected the amount of body protein lost, and was lowest (P < 0.05) in sows that lost the most protein. After d 20, piglet growth rate decreased (P < 0.05) in a manner related to the amount of body protein lost. At weaning, ovarian function was suppressed in sows that had mobilized the most body protein; they had fewer mediumsized follicles (>4mm; P < 0.05), their follicles contained less (P < 0.01) follicular fluid, and had lower estradiol (P < 0.05) and IGF-I (P < 0.10) contents. Culture media containing 10% pooled follicular fluid (vol/vol) from high-protein-loss sows were less able to support nuclear and cytoplasmic maturation of oocytes in vitro, evidenced by more oocytes... [ABSTRACT FROM AUTHOR]

A limited ability to cope with environmental stressors (cold, disease, limited nutrition), particularly over the first 2 to 3 d of life, predisposes the piglet to relatively high rates of neonatal morbidity and mortality. Due to the serious economic impact, numerous surveys of preweaning losses have been conducted over the last century. Although losses are still significant, the existing literature indicates a significant improvement in piglet survival over time, as determined by reports of 35% preweaning mortality in 1924 and 13 to 15% in 2000. Major sources of mortality have been categorized as overlying by the sow, insufficient energy intake, and disease. Causes of mortality may be more closely linked with one another than previously believed. Interactions exist between disease, thermoregulation, and nutrition. Piglets with disease and nutritional problems experience hypothermia and express altered behaviors that increase the likelihood of their being laid on by the sow. High probabilities of neonatal losses are associated with low birth weights, cold ambient temperatures, and scouring. An understanding of the interactions between environmental stressors and the biology of the piglet forms the basis for strategies and recommendations for improving preweaning survival. [ABSTRACT FROM AUTHOR]

Presents a study which determined the effects of feeding level and major dietary energy source used during lactation on sow milk composition, piglet body composition and energy balance of sows. Experimental procedures; Results and discussion; Conclusion.

Presents information on a study which investigated whether a reduction of excess dietary amino acids would improve feed intake and performance of lactating sows experiencing heat stress. Materials and methods; Results and discussion.

Part III. Investigates whether making gilts anabolic during lactation, by providing them with extra nutrition, would increase milk production and pig growth. Materials and methods used; Indication that lactating sows mobilize body reserves to support milk production; Results and discussion.

Part II. Focuses on an experimental model which was designed to study nitrogen (N) partitioning in lactating primiparous sows, at three levels of nutrient intake. Materials and methods used; Why sows mobilize protein reserves; Results and discussion.

Presents information on the high dietary calcium concentrations among pigs. What occurred in many swine experiments; Formulation of the basal corn-soybean meal grower phase diet; Information on these pigs.

The article focuses on a study conducted to analyze the impact of wide calcium and phosphorus ratios on weanling pigs' supplemental phytase efficacy. It refers to the use of 96 weanling pigs in a 4-wk experiment fed in combination with two Phosphorus levels and two phytase levels. It found 16% increase in phytase efficacy for bone measurements, improving performance and digestibility.

The article focuses on a study conducted to examine feed intake patterns during lactation in commercial swine herds. It refers to the use of a database containing 25,719 farrowing and 19,393 subsequent litter records of 30 commercial farms and daily feed intake records of 25,040 lactating sows. It found that substantial individual sow and farm variation in overall feed intake during lactation.