Microbial use of recycled urea is dependent on the level and frequency of degradable intake protein supplementation

Protein supplementation increases utilization (intake and digestion) of low-quality forage and ultimately animal performance. Despite its effectiveness, protein supplementation is often expensive. One strategy to reduce the cost of supplementation is to supplement less frequently than daily, generally every other day or every third day. By reducing the frequency of supplementation, the cost of delivering the supplement is reduced. Reducing the frequency of supplementation is an effective strategy for reducing cost, and it only minimally impacts animal performance, with less frequent supplementation resulting in slightly greater losses of body condition score and body weight during the winter supplementation period. Urea recycling, the transfer of urea from the animal\u27s body to the gastrointestinal tract, has been suggested as a mechanism that allows infrequently supplemented cattle to perform similarly to cattle supplemented daily. However, little data is available to substantiate this claim, and such data would be useful in helping nutritionists better understand nitrogen metabolism in infrequently supplemented ruminants. Our objective was determine the role of urea recycling in meeting ruminal nitrogen requirements in infrequently supplemented cattle fed low-quality forage

Microbial use of recycled urea is dependent on the level and frequency of degradable intake protein supplementation

Protein supplementation increases utilization (intake and digestion) of low-quality forage and ultimately animal performance. Despite its effectiveness, protein supplementation is often expensive. One strategy to reduce the cost of supplementation is to supplement less frequently than daily, generally every other day or every third day. By reducing the frequency of supplementation, the cost of delivering the supplement is reduced. Reducing the frequency of supplementation is an effective strategy for reducing cost, and it only minimally impacts animal performance, with less frequent supplementation resulting in slightly greater losses of body condition score and body weight during the winter supplementation period. Urea recycling, the transfer of urea from the animal’s body to the gastrointestinal tract, has been suggested as a mechanism that allows infrequently supplemented cattle to perform similarly to cattle supplemented daily. However, little data is available to substantiate this claim, and such data would be useful in helping nutritionists better understand nitrogen metabolism in infrequently supplemented ruminants. Our objective was determine the role of urea recycling in meeting ruminal nitrogen requirements in infrequently supplemented cattle fed low-quality forage

Supplementation with undegradable intake protein increases utilization of low-quality forage and microbial use of recycled urea

Low-quality forage utilization (intake and digestion) is improved by protein supplementation. Typically, the recommendation is to select supplements that are high in degradable intake protein because this fraction of the protein directly addresses the ruminal nitrogen deficiency that exists when low-quality forages are fed. However, the low cost of byproducts (e.g., distiller’s grains) that are high in undegradable intake protein makes them an attractive source of supplemental protein even though the response per unit of supplemental protein is less for undegradable protein than for degradable protein. One of the primary barriers to utilizing highly undegradable protein sources as supplements is the lack of information regarding their ability to provide nitrogen to ruminal microbes and, ultimately, their effectiveness as protein supplements to cattle fed low-quality forage. Because the protein is not ruminally degraded, the use of undegradable protein supplements to meet ruminal nitrogen requirements depends on the ability to recycle nitrogen to the rumen in the form of urea. Subsequently, the urea is utilized as a nitrogen source by ruminal microbes. Our objective was to measure how much nitrogen is recycled as urea and how much recycled nitrogen is used to meet microbial growth requirements when increasing amounts of undegradable intake protein were provided to steers consuming prairie hay. This data will be useful in developing supplementation strategies for cattle consuming low-quality forage

Supplementation with degradable intake protein increases low-quality forage utilization and microbial use of recycled urea

A common production practice throughout the United States is to supplement protein to cattle consuming low-quality forage (forage with a crude protein content of less than 7%) in order to improve animal performance (i.e., maintain body condition score and body weight) during the winter. Protein supplementation increases forage utilization (intake and digestion) and cow performance by supplying ruminal microbes with protein that is essential for microbial growth. Increased microbial activity in turn provides sources of both protein and energy to the cow. In addition to the protein that is fed and degraded in the rumen, ruminants have the ability to recycle urea—the same compound found in fertilizer and cattle feed—to the rumen, where microbes can use the urea to fulfill a portion of their nitrogen requirement. Although nutritionists know that recycling occurs, we have inadequate data to describe this process and, subsequently, the contribution from recycled urea is not adequately included in our present cattle feeding systems. Previous research at Kansas State University has clearly demonstrated that the greatest response to supplemental protein occurs when the supplemental protein is highly degraded within the rumen, as the degradable fraction of protein is directly available to ruminal microbes. The current project’s objective was to measure how much recycled urea is used to meet the microbial nitrogen requirement when increasing amounts of degradable intake protein were provided to steers consuming low-quality forage. Researchers hoped to generate data useful in refining supplementation recommendations for cattle consuming low-quality forage

Substituição parcial de silagem de milho por farelo de glúten de milho desidratado na alimentação de vacas holandesas em lactação Partial replacement of corn silage by corn gluten feed in the feeding of dairy Holstein cows in lactation

Objetivou-se estudar o efeito da substituição de parte da silagem de milho por farelo de glúten de milho (FGM-21) desidratado na produção e composição do leite e nos parâmetros sangüíneos de vacas em lactação e avaliar economicamente essa substituição. Foram avaliados os níveis 0, 8 e 16% de inclusão de FGM-21 (% MS) nas dietas. Trinta vacas foram utilizadas no estudo da produção e composição do leite e 15 vacas no estudo dos parâmetros sangüíneos. O delineamento experimental foi quadrado latino 3 <FONT FACE=Symbol>&acute;</FONT> 3 com dez replicações. Houve diferença entre as dietas para a produção de leite e a produção de leite corrigida para 3,5% de gordura. As demais características estudadas não diferiram entre as dietas. Para produção de leite, foram obtidos os valores de 22,44; 23,69 e 23,88 kg/vaca/dia; para produção de leite corrigida para 3,5% de gordura, 23,25; 24,71 e 24,44 kg/vaca/dia; para porcentagem de gordura, 3,69; 3,76 e 3,65%; para proteína no leite, 3,22; 3,20 e 3,25%; lactose, 4,29; 4,32 e 4,31%; sólidos totais, 12,12; 12,23 e 12,14%; N-uréico no leite, 16,57; 16,50 e 14,96 mg/dL; N-uréico plasmático, 19,92; 21,17 e 20,21 mg/dL; e para glicose sérica, 55,69; 56,50 e 54,78 mg/dL nos níveis 0, 8 e 16% de FGM-21, respectivamente. A dieta com 16% de FGM-21 resultou em maior lucro.<br>The objective was to study the effects of partial replacing of corn silage by corn gluten feed (CGF-21) dehydrated on milk production and composition of milk and in the blood parameters of dairy cows, beyond the economic evaluation. Inclusion levels of 0, 8 and 16% of CGF-21 (% DM) to the diets were evaluated. Thirty cows were used for study of milk production and composition and fifteen cows for blood parameters study. A 3 x 3 Latin Square experimental design with ten replications was used. There was difference among diets for milk yield and for 3.5% fat correct milk. No difference among diets was observed for the other studied characteristics. The results obtained for milk yield were: 22.44, 23.69 and 23.88 kg/anim.d and for 3.5% fat correct milk were: 23.25, 24.71 and 24.44 kg/anim.d, respectively, for the inclusionj levels of CGF-21 for the inclusion levels of 0, 8 and 16% of CGF-21 in the diet. The results obtained for the composition of milk were: percentage of fat, 3.69, 3.76 and 3.65%; milk protein, 3.22; 3.20 and 3.25%; lactose, 4.29, 4.32 and 4.31%; total solids, 12.12, 12.23 and 12.14%; N-ureic milk, 16.57, 16.50 and 14.96mg/dL, and for blood parameters were: plasma N ureic, 109.92, 21.17 and 20.21 mg/dL, seric glucose, 55.69, 56.50 and 54.78 mg/dL, respectively, for the inclusion levels of 0, 8 and 16% of CGF-21 in the diet. The diet with the inclusion of 16% of CGF-21 result on a greater profit