Characterization of Awassi lamb fattening systems: a Syrian case study.

Intensive lamb fattening systems are evolving in developing Middle Eastern countries due to high demand for lambs at favorable prices; however, little is known about their characteristics and constraints. A survey was conducted in Syria involving 241 farmers to characterize the fattening production systems and main constraints, with emphasis on feeding, management, labor, and marketing. Most farmers (90%) considered the income from fattening to be from medium to high, and 57% expressed that lamb fattening along with alternative income sources compose the family's livelihood strategies. Fattening systems offer employment to family members. Market price was the main decision factor to buy and sell lambs, but this was only part of various marketing aspects. Male lambs usually bought at markets at the mean age of 4 months (mean weight of 31 kg) are sold after fattening at a 50-60 kg weight range. The average yearly fattening cycle was 2.7 batches, and the average number of lambs per batch was 232. For 65% (n = 241) of the farmers the major constraint to fattening was feeding cost, and for about a half of farmers (51%, n = 241), disease outbreaks and prices for veterinarian services constituted the second important constraint. Research on least-cost fattening diets and curbing disease problems to increase farmer's income margins is needed. It is expected that due to existing commonalities, the information emerging from this study regarding major constraints to Awassi lamb fattening systems could be useful for an across-synthesis on Awassi fattening production in the region.

Optimization of rate and efficiency of dietary nitrogen utilization through the use of animal by-products and(or) urea and their effects on nutrient digestion in Holstein steers.

The objective of this N balance study was to determine the potential for improving the efficiency and rate of dietary N utilization in Holstein steers by feeding an amino acid-balanced mixture of animal by-product protein sources in combination with urea. The Beef NRC 1996 Model Level 2 was used to formulate a corn-based (86:14 concentrate-hay) control diet with soybean meal as the primary N supplement that would provide ME and metabolizable protein (MP) allowable ADG of 1.4 kg in 250-kg steers with an estrogenic implant and fed an ionophore. A combination of porcine meat and bone meal, fish meal, hydrolyzed feather meal, and blood meal was also formulated as an undegradable intake protein (UIP) blend to complement those amino acids (AA) derived from microbial protein synthesis. Four steers with an average initial BW of 259 kg were assigned in a 4 x 4 Latin square design to treatments consisting of control, two levels of UIP inclusion (2.6 and 5.2%; DM basis) in combination with urea, and a negative control "urea diet" containing no UIP and no SBM. The steers were fed at hourly intervals 95% of ad libitum intake and were injected with 500 microg of estradiol-17beta twice daily. Nitrogen intakes were 155, 160, 162, and 145 g/d, and N balances were 47, 51, 42, and 47 g/d when the 0, 2.6, 5.2% UIP and the urea diets were fed, respectively. Nitrogen balance was reduced with the 5.2% UIP diet (P < 0.05), and was less than the capacity estimate derived from abosmasal casein infusion studies. Apparent N digestibilities averaged 69%, but DM, OM, and nonstructural carbohydrate digestibilities were significantly reduced for the urea diet. Feeding 5.2% UIP in the diet reduced (P < 0.05) the biological value from 46 to 38%, which was accompanied by a significant elevation of plasma urea N. Results indicate that genetic capacity for N retention was approximately 51 g/d. Results demonstrate that use of an AA-balanced blend of animal by-product protein sources did not improve the efficiency of dietary N usage when added to corn-based diets formulated with the Beef NRC 1996 Model Level 2 to meet nutrient requirements of rapidly growing steers. Using urea as the only N supplement achieved equal rate and efficiency of N use.

Effects of a dietary mixture of meat and bone meal, feather meal, blood meal, and fish meal on nitrogen utilization in finishing Holstein steers.

Our objective was to determine to what extent rate and efficiency of protein gain in finishing cattle can be enhanced by feeding an amino acid-balanced mixture of undegraded intake proteins. The Cornell Net Carbohydrate and Protein System (CNCPS) model was used to formulate a corn-based diet that would meet the rumen requirements for 410-kg large-framed steers with an estrogen implant and fed an ionophore. The CNCPS model was also used to formulate a highly undegradable intake protein (UIP) mixture from meat and bone meal, blood meal, fish meal, and hydrolyzed feather meal to provide the amino acids needed to supplement those derived from microbial protein to better meet amino acid requirements for growth. Four Holstein steers weighing 407 kg were offered a 90:10 concentrate-forage diet at hourly intervals at 95% of ad libitum intake. The steers were injected with 500 microg of estradiol-17beta at 12-h intervals to mimic the effects of an estrogenic implant. Treatments planned consisted of inclusion of the UIP mixture at 0, 2.5, 5, and 7.5% of the diet DM. Dry matter intake was fixed at 6.4 kg/d, and DM digestibility was not significantly affected by varying the amount of UIP addition. Apparent digestibility of N increased (P = .011) from 63.8 to 65.8, 70.7, and 71.5%, the amount of N absorbed increased (P = .001) from 73 to 84, 100, and 106 g/d, and N balance increased (P = .003) from 20 to 30, 33, and 39 g/d when UIP was fed at 0, 2.6, 5.2, and 7.8% of diet DM, respectively. The efficiency of N use increased 39.7%, and biological value increased 31.6% when the UIP mixture was added to the diet. Circulating concentrations of plasma urea N (PUN) were increased (P = .017) from 4.5 for the control diet to 5.7, 6.2, and 6.1 mg/dL when the UIP mixture was added at 2.6, 5.2, and 7.8%, respectively. Corresponding IGF-I concentrations were also increased from 491 to 558 and 624 ng/mL with 2.6 and 5.2% levels of UIP addition. Plasma glucose, NEFA, and insulin concentrations were not affected by feeding the UIP mix. The rate and efficiency of N use for growth improved with addition of an amino acid-balanced UIP mixture to the diet.