The Effect of Protected Amino Acid Supplementation on the Performance of Dairy Cows Receiving Grass Silage Plus Soyabean Meal

Author(s):  
J.C. Robert ◽  
B.K. Sloan ◽  
C. Denis

Methionine has been shown to be the first-limiting amino acid for milk protein synthesis in lactating dairy cows fed maize silage-based diets complemented with soyabean meal (Sloanet al., 1992) (Pisulewskiet al., 1993). Thus, the aim of this trial was to investigate the hypothesis that methionine was first-limiting or if not at least colimiting with lysine for milk protein synthesis in dairy cows fed grass silage complemented with soyabean meal.8 muciparous and 4 primiparous dairy cows six weeks into lactation were randomly allocated to three 4x4 Latin squares (cows and heifers separately), each period containing 2 weeks. The four treatments consisted of Tl = Control ; T2 = 3.7 g methionine ; T3 = 7.4 g methionine ; T4 = 7.4 g methionine and 22.2 lysine . All figures relate to estimated intestinally available amino acids, g/day (Smartamine™technology Rhône-Poulenc Animal Nutrition). The basal ration was a second cut grass silage offeredad libitumplus 0.57 kg of hay plus an average 10.9 kg concentrate.

1998 ◽  
Vol 1998 ◽  
pp. 206-206
Author(s):  
R.J. Dewhurst ◽  
D. Wadhwa ◽  
L.P. Borgida ◽  
D.W.R. Davies ◽  
W.J. Fisher

Falling prices for cereals and beneficial effects on milk protein concentrations may promote greater inclusions of rapidly fermented ingredients in dairy rations. There is, however, a limit to the inclusion of these feeds into dairy rations beyond which performance declines due to sub-acidosis and related disorders. The feed compounder will need to be able to set limits on levels of feeding concentrates according to these risks. The objective of this experiment was to evaluate the effect of feeds of different acidogenicity (Wadhwa et al., 1998) on lactation performance of dairy cows offered diets based on grass- or maize-silage.Twelve multiparous Holstein-Friesian cows in the third month of lactation were used for this experiment. The experimental design involved adaptation and covariance recording on a standard diet (grass silage and 10 kg concentrates per day), followed by three 21-day experimental periods arranged as four 3x3 Latin Squares. The Latin Squares were constrained to a single forage to avoid difficulties in changeovers between grass silage and maize silage.


Author(s):  
F.P. O'Mara ◽  
J.J. Murphy ◽  
M. Rath

Milk protein synthesis may be limited by amino acid (AA) flow to the duodenum. This can be increased by increasing the flow of microbial AA's or undegraded feed AA's. This experiment was carried out to determine the effect on milk production and nutrient flows at the duodenum of including fishmeal (120g/kg) in the supplement to grass silage at two levels of supplement feeding.The treatments, arranged in a 2x2 factorial, were 1.) 3.5 kg/day of 0% fishmeal supplement (L-UDP), 2.) 7 kg/day of L-UDP, 3.) 3.5 kg/day of 12% fishmeal supplement (H-UDP), and 4.) 7 kg/day of H-UDP. Supplements were fed to 3 6 Friesian cows in a 4x4 multiple Latin-square trial with three week periods to determine production responses, and to four ruminally and duodenally cannulated cows to determine rumen fermentation and nutrient flows. Flows were determined by the dual marker technique of Faichney (1975) using cobalt-EDTA and ytterbium acetate as liquid and solid phase markers respectively. Purines were used as the bacterial marker (Zinn and Owens, 1986). Degradability of the feeds was measured in 3 other cows using the small bag technique described by De Boer et al. (1987).


Author(s):  
J.R. Newbold ◽  
B.R. Cottrill ◽  
R.M. Mansbridge ◽  
J.S. Blake

Few data are available to evaluate the Metabolisable Protein (MP) System (AFRC, 1992) as an aid to ration formulation for dairy cows. Responses of lactating dairy cows to MP were evaluated in two experiments.In Experiment One, groups of 10 Holstein cows were offered grass silage ad libitum and 7kg DM/d of one of six (treatments 1-6) compound foods from 39d after calving, for eight weeks. All rations were isoenergetic, assuming silage intake of 11kg DM/d (typical for the herd). Ratios between MP supply (calculated from in situ protein degradability measurements) and requirement (calculated for a standard cow: 565kg live weight, 281 milk/d, 40g/kg butterfat, 33g/kg milk protein, liveweight change =0kg/d) were 1.00, 1.02, 1.06, 1.06, 1.1 and 1.17 for treatments 1-6, respectively.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Virginia L. Pszczolkowski ◽  
Sebastian I. Arriola Apelo

Abstract For dairy production systems, nitrogen is an expensive nutrient and potentially harmful waste product. With three quarters of fed nitrogen ending up in the manure, significant research efforts have focused on understanding and mitigating lactating dairy cows’ nitrogen losses. Recent changes proposed to the Nutrient Requirement System for Dairy Cattle in the US include variable efficiencies of absorbed essential AA for milk protein production. This first separation from a purely substrate-based system, standing on the old limiting AA theory, recognizes the ability of the cow to alter the metabolism of AA. In this review we summarize a compelling amount of evidence suggesting that AA requirements for milk protein synthesis are based on a demand-driven system. Milk protein synthesis is governed at mammary level by a set of transduction pathways, including the mechanistic target of rapamycin complex 1 (mTORC1), the integrated stress response (ISR), and the unfolded protein response (UPR). In tight coordination, these pathways not only control the rate of milk protein synthesis, setting the demand for AA, but also manipulate cellular AA transport and even blood flow to the mammary glands, securing the supply of those needed nutrients. These transduction pathways, specifically mTORC1, sense specific AA, as well as other physiological signals, including insulin, the canonical indicator of energy status. Insulin plays a key role on mTORC1 signaling, controlling its activation, once AA have determined mTORC1 localization to the lysosomal membrane. Based on this molecular model, AA and insulin signals need to be tightly coordinated to maximize milk protein synthesis rate. The evidence in lactating dairy cows supports this model, in which insulin and glucogenic energy potentiate the effect of AA on milk protein synthesis. Incorporating the effect of specific signaling AA and the differential role of energy sources on utilization of absorbed AA for milk protein synthesis seems like the evident following step in nutrient requirement systems to further improve N efficiency in lactating dairy cow rations.


1993 ◽  
Author(s):  
Gabriella A. Varga ◽  
Amichai Arieli ◽  
Lawrence D. Muller ◽  
Haim Tagari ◽  
Israel Bruckental ◽  
...  

The effect of rumen available protein amino acids and carbohydrates on microbial protein synthesis, amino acid flow and performance of high yielding dairy cows was studied. A significant relationship between the effective degradabilities of OM in feedstuffs and the in vivo ruminal OM degradation of diets of dairy cows was found. The in situ method enabled the prediction of ruminal nutrients degradability response to processing of energy and nitragenous supplements. The AA profile of the rumen undegradable protein was modified by the processing method. In a continuous culture study total N and postruminal AA flows, and bacterial efficiency, is maximal at rumen degradable levels of 65% of the CP. Responses to rumen degradable non carbohydrate (NSC) were linear up to at least 27% of DM. Higher CP flow in the abomasum was found for cows fed high ruminally degradable OM and low ruminally degradable CP diet. It appeared that in dairy cows diets, the ratio of rumen degradable OM to rumenally degradable CP should be at least 5:1 in order to maximize postruminal CP flow. The efficiency of microbial CP synthesis was higher for diets supplemented with 33% of rumen undegradable protein, with greater amounts of bacterial AA reaching the abomasum. Increase in ruminal carbohydrate availability by using high moisture corn increased proportions of propionate, postruminal nutrients flow, postruminal starch digestibility, ruminal availability of NSC, uptake of energy substrates by the mammory gland. These modifications resulted with improvement in the utilization of nonessential AA for milk protein synthesis, in higher milk protein yield. Higher postruminal NSC digestibility and higher efficiency of milk protein production were recorded in cows fed extruded corn. Increasing feeding frequency increased flow of N from the rumen to the blood, reduced diurnal variation in ruminal and ammonia, and of plasma urea and improved postruminal NSC and CIP digestibility and total tract digestibilities. Milk and constituent yield increased with more frequent feeding. In a study performed in a commercial dairy herd, changes in energy and nitrogenous substrates level suggested that increasing feeding frequency may improve dietary nitrogen utilization and may shift metabolism toward more glucogenesis. It was concluded that efficiency of milk protein yield in high producing cows might be improved by an optimization of ruminal and post-ruminal supplies of energy and nitrogenous substrates. Such an optimization can be achieved by processing of energy and nitrogenous feedstuffs, and by increasing feeding frequency. In situ data may provide means for elucidation of the optimal processing conditions.


1997 ◽  
Vol 1997 ◽  
pp. 87-87
Author(s):  
T.W.J. Keady ◽  
J.J. Murphy

Quota restricts the volume and butterfat content of milk at farm level. However there is no restriction on milk protein concentration. In a previous study in the present series, sucrose supplementation of cows in late lactation offered grass silage based diets increased milk protein concentration, while supplementation with sucrose and fishmeal increased protein concentration and the yields of milk, protein and fat plus protein equivalent to, or greater than, that obtained from the parent herbage. The present study was undertaken to evaluate the effects of partially replacing a concentrate supplement with sucrose and/or fishmeal, over a range of concentrate feed levels, on forage intake, milk production and composition.Herbage was harvested from the primary growth of a predominantly perennial ryegrass sward, unwilted, precision chopped and treated with a formic acid based additive (Add-Safe, Trouw Nutrition) at 2.85 l/t. A concentrate was formulated consisting of unmolassed sugar beet pulp, barley, soyabean meal and minerals and vitamins. Four complete diets were prepared consisting of the silage and either concentrate (20 g/kg fresh silage) (SC), concentrate and sucrose (each at 10 g/kg fresh silage) (SCS) concentrate and fishmeal (each at 10 g/kg fresh silage) (SCF) or sucrose and fishmeal (each at 10 g/kg fresh silage) (SSF).


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