Performance and carcass traits of early-weaned steers receiving either a pasture growing period or a finishing diet at weaning.
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A 2-yr study was conducted to evaluate 1) steers fed ad libitum high concentrate after weaning (CONC), or 2) steers grown on pasture for 82 d, followed by high-concentrate finishing (PAST), on the performance and carcass traits of 74 early-weaned (117 d of age) steers. Potential breed differences were evaluated using crossbred steers of three types: 1) 3/4 Angus x 1/4 Simmental (BRI), 2) 3/4 Simmental x 1/4 Angus (CON), and 3) 1/2 Wagyu x 1/4 Angus x 1/4 Simmental (WAG). Steers were randomly assigned within breed to the two treatments. There was no interactions (P > .10), so the data were pooled over years. The CONC steers had an ADG that was .17 kg/d higher (P = .0001), intake 1.09 kg/d lower (P = .0001), and gain:feed ratio .013 unit better (.190 vs .177, P = .008) than PAST steers overall. Growing treatment did not affect total concentrate consumed (P = .97). The BRI steers required 31 d less than did CON steers (P = .008), and 23 d less than WAG steers (P = .05) when fed to a constant fat end point (1.1 cm). The BRI steers exhibited an ADG .16 kg/d higher (P = .0003), tended (P = .07) to have an ADG intake .49 kg/d higher, and exhibited gain:feed .01 unit better (.189 vs 180) than WAG steers. When compared with CON steers, BRI steers consumed 310 kg less total concentrate (P = .0003). No differences (P > .38) were observed between growing treatments for carcass characteristics or sensory attributes except that CONC steers tended (P = .11) to improve percentage of steers grading Average Choice or higher by 47% over PAST steers. The WAG steers had a 76-unit higher marbling score (1,000 = Small00, 1,100 = Modest00) (P = .006) than BRI steers, resulting in 19% more (P = .09) steers grading > or = Choice and 82% more (P = .03) grading > or = Average Choice. Liver (P = .15) and rumen (P = .01) weights as a percentage of hot carcass weight were reduced for CONC steers. The CONC steers had higher gain, lower intake, better efficiency, reduced liver and rumen weights, and consumed the same amount of total concentrate when compared with PAST steers. The BRI steers had less finishing days and lower daily intake compared with CON steers. The WAG steers had more days finishing, lower gain, lower intake, more undesirable efficiencies, consumed the same amount of total concentrate, and improved quality grades compared with BRI steers. (+info)
Effect of postweaning feeding on the performance and energy balance of female rabbits at different physiological states.
(26/6328)
The feeding of a high-fiber and low-energy diet to young rabbit does from weaning to the first kindling was used to modify their body reserves, stimulate their energy intake, and reduce the energy deficit during the first lactation. Rabbits (53 per group) were given ad libitum access to either a control or high-fiber diet (CP, 17.6 vs 15.8% of DM; crude fiber, 15.5 vs 19.9% of DM; digestible energy, 2,565 vs 2,261 kcal/kg of DM, respectively) from weaning to their first kindling. During lactation, both groups received the same diet, which contained 19.3% CP, 16.5% crude fiber, and 2,634 kcal/kg digestible energy (dry matter basis). Four comparative slaughters were performed to estimate the chemical and energy balance of rabbit does at different physiological states: at the beginning of the trial (12 rabbits, 45 d of age), at mating (10 rabbits per group, 136 d), at kindling (10 rabbits per group, 167 d), and at the end of lactation (12 and 11 rabbits for the control and the high-fiber group, 197 d). Large changes in body weight and composition were observed between slaughters. From 45 d to mating, doe body fat and energy increased 7.93 and 4.64 times the initial content, respectively. During pregnancy, body protein concentration decreased from 203 to 186 g/kg. At the end of lactation, body fat and energy concentration were reduced to values close to those measured at 45 d of age. Dietary treatment affected body chemical and energy balance during pregnancy and lactation but not reproductive and lactational performance. The high-fiber diet stimulated feed intake from weaning to the first kindling but not dietary energy intake. During lactation, the rabbits fed the high-fiber diet ate 10 kcal x d(-1) x kg live weight(-.75) more and lost less body fat (-405 vs -504 g) and body energy (-3,628 vs -4,294 kcal) than the does fed the control diet (P < .001). In the same period, all does showed water and protein retention (185 and 45 g, on average) regardless of dietary treatment. In conclusion, feeding young does a high-fiber diet until their first kindling reduced the chemical and energy body deficit at the end of the first lactation. (+info)
Nutrient management procedures to enhance environmental conditions: an introduction.
(27/6328)
The advent of concentrated, large animal production units presents a monumental challenge for the effective management of nutrients in animal manure. This symposium was organized to address the issue of the environmental impact of animal production and to offer suggestions on nutrient management procedures for reducing the environmental impact. There were four presentations on environmental concerns of animal manure that covered the topics of using the severe Dutch legislation that limits the amounts of nitrogen and phosphate in the manure allowed for application on cropland, potential for reducing odorous compounds in swine manure, alternatives to reduce the environmental impact of large swine production units, and, finally, perspectives on nutrient management procedures from a swine integrator's viewpoint. This introduction to the symposium highlights the major areas discussed within each of the four presentations. (+info)
Potential for reduction of odorous compounds in swine manure through diet modification.
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Recent public concern about air pollution from pork production units has prompted more research to develop methods to reduce and control odors. Masking agents, enzymes and bacterial preparations, feed additives, chemicals, oxidation processes, air scrubbers, biofilters, and new ventilation systems have been studied. Research relating the effects of the swine diet on manure odors has been scarce. Introducing feed additives to bind ammonia, change digesta pH, affect specific enzyme activity, and mask odors has been either costly or not consistently successful. Recent research emphasis has focused on manipulating the diet 1) to increase the nutrient utilization of the diet to reduce excretion products, 2) to enhance microbial metabolism in the lower digestive tract to reduce excretion of odor-causing compounds, and 3) to change the physical characteristics of urine and feces to reduce odor emissions. Primary odor-causing compounds evolve from excess degradable proteins and lack of specific fermentable carbohydrates during microbial fermentation. Reductions in ammonia emissions by 28 to 79% through diet modifications have been reported. Limited research on reduction of other odorous volatile organic compounds through diet modifications is promising. Use of synthetic amino acids with reduced intact protein levels in diets significantly reduces nitrogen excretions and odor production. Addition of nonstarch polysaccharides and specific oligosaccharides further alters the pathway of nitrogen excretion and reduces odor emission. Continued nutritional and microbial research to incorporate protein degradation products, especially sulfur-containing organics, with fermentable carbohydrates in the lower gastrointestinal tract of pigs will further control odors from manure. (+info)
A swine integrator's perspective on nutrient management procedures.
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The goal of pork producers is to operate in a sustainable manner that includes among other requirements, environmental soundness, social acceptability, and profitability. Gains in efficiency have reduced nutrient by-products per pig, but competitive forces have led to specialization, larger farms, and concentrated areas of production that have resulted in new opportunities related to nutrient management. Available technology uses on-farm processing or storage facilities, and manure is applied to the land as an organic fertilizer. Knowledge of nutrient content of soils and crop uptake of nutrients is incorporated into manure application and crop removal plans to prevent either runoff or nutrient buildup on the land. This is to ensure water quality protection. Existing systems are adequate but lack flexibility, require effective management, may not have been incorporated into older farms, and do not offer obvious solutions to odor concerns. Cost-effective alternatives should address those needs. Advancement in nutrient management procedures will likely accelerate the ongoing changes in the structure of the swine industry. (+info)
Relations between body weight, feed intake, daily weight gain, and exocrine pancreatic secretion in chronically catheterized growing pigs.
(30/6328)
The aim of this investigation was to develop models that would make it possible to correct exocrine pancreatic secretion data for the effect of BW and feed intake in growing pigs. In addition, the significance of exocrine pancreatic secretion for daily weight gain (DWG) was studied. Data were used from 10 pigs (16 to 32 kg BW) surgically fitted with chronic pancreatic catheters. The samples were collected under controlled conditions for two to five experimental days per animal (a total of 39 observations), during 2 h preprandially and during 2 h when feeding (postprandially). The exocrine pancreatic secretion traits included the hourly output of volume, the amount of protein, and trypsin and amylase activities. Multiple linear regressions were used to develop models to describe exocrine pancreatic secretion. The individual pig was the most important source of variation in the model. With increasing BW, 7 out of 10 pigs showed an increase in exocrine pancreatic secretion. However, the slopes of the regression lines differed between animals, which made it impossible to develop general models for the correction of secretion data for the effect of BW. Postprandial exocrine pancreatic secretion was always higher than preprandial secretion, but the amount of feed intake per se did not seem to affect secretion. Exocrine pancreatic secretion and DWG were positively correlated. We concluded that, under the present circumstances, expressing secretion per kilogram BW or kilogram feed intake was not feasible. Expressing secretion per hour was the best way to present the data. (+info)
Fractionation of fiber and crude protein in fresh forages during the spring growth.
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The composition of the fiber and CP of alfalfa, bromegrass, and endophyte-free and -infected tall fescue forages was compared during the spring growth from vegetative to reproductive stages. Forages were sampled from April 27 to June 6 in 1994, and from April 27 to June 11 in 1995, with 11 and 12 harvest dates, respectively. Total dietary fiber (TDF) was fractionated into insoluble and soluble fiber (SF). The CP of the forages was fractionated into nonprotein N (A), soluble CP (B1), insoluble CP that was soluble in neutral detergent (B2), CP insoluble in neutral detergent but soluble in acid detergent (B3), and CP insoluble in acid detergent (C). Effects of year, forage species, and harvest dates (day as a covariable) were included in the model. Across harvest dates, alfalfa (A) had lower (P < .01) TDF and higher (P < .01) SF concentrations than grasses (GR) (A: 49.9 and 14.4% and GR: 60.4 and 4.5% [OM basis] for TDF and SF, respectively). Alfalfa had higher (P < .01) CP (20.6% DM) than GR (15.3%). The rate of decrease in CP (% DM) across days was higher (P < .01) for bromegrass (-.4%/d) than for the other forages (-.29%/d). Fraction A (% of CP) was not different (P = .24) among forages (22.5%), but B1 was higher (P < .01) in A (17.1%) than in GR (13.2%). The B2 fraction (% of CP) was higher (P < .01) in A compared with GR (51.6 vs 45.9%, respectively). Alfalfa had lower (P < .01) B3 (3.0% of CP) than bromegrass (18.6%) and tall fescue (13.2%). Fraction C was not different (P = .23) among forages (3.8%). Fractions A, B1, and C (% of CP) did not change (P > .05) across days for all forages. Fraction B2 (% of CP) decreased across days in A (-.21%/d) but was not affected in GR. Fraction B3 (% of CP) increased (P < .05) in A (.1%/d), decreased in endophyte-infected tall fescue (-.20%/d), and did not change (P > .05) in the other forages. Crude protein and fiber composition were affected more by forage species than by maturity. The CP and NDF concentrations were more affected by maturity. Insoluble fractions but not soluble fractions of CP were affected by maturity. (+info)
Degradation of two protein sources at three solids retention times in continuous culture.
(32/6328)
Effects of solids retention times (SRT) of 10, 20, and 30 h on protein degradation and microbial metabolism were studied in continuous cultures of ruminal contents. Liquid dilution rate was constant across all retention times at .12 h(-1) (8.3 h mean retention time). Two semipurified diets that contained either soybean meal (SBM) or alfalfa hay (ALFH) as the sole nitrogen source were provided in amounts that decreased as SRT was increased. Digestion coefficients for DM, NDF, and ADF increased with increasing SRT. Digestion coefficients for nonstructural carbohydrates were higher in the SBM diet than in the ALFH diet but were not affected by SRT. Protein degradation in the ALFH diet averaged 51% and was unaffected by retention time. In the SBM diet, digestion of protein was 77, 78, and 96% at 10-, 20-, and 30-h retention times, respectively. Microbial efficiency decreased with increasing SRT and was greater for the SBM than for the ALFH diet. Efficiencies ranged from 30.6 to 35.7 and 20.8 to 29.2 g of N/kg of digested DM for the SBM and ALFH diets, respectively, as SRT decreased from 30 to 10 h. The diaminopimelic acid content of the microbes increased as SRT increased, indicating that changes in microbial species occurred owing to passage rates. From these results, we concluded that the digestibility decreases associated with increased ruminal turnover rates may be less for nonstructural carbohydrates and protein than for the fiber fractions. (+info)