Document Type : Research Articles
Authors
Department of Animal Science, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran
Abstract
Introduction: Barley grain can provide energy and protein to lactating dairy cows; however, feeding high levels of barley grain may increase the risk of developing rumen disorders with extensive consequences for health, welfare and continuity of milk production. Various barley processing (chemically and physically) is critical to prevent ruminal acidosis, enhance digestion, nutrient utilization, and promote productivity. Steam-infrared heated-flaking is a physical-specific process and it impresses on starch gelatinization and protein denaturation which may modify both site and rate of digestion. Treating barley grain with lactic acid have been shown to alter the chemical composition and the nutritional value of treated grains. Barley grains ammunition treatment increased nitrogen content, effective rumen degradable and intestinal digestibility of nitrogen. Plant extract through the selective effect on certain rumen bacteria and the attachment and pattern of their colonization of starchy grain such as barley grain may alter starch degradation.
Materials and Methods: To prepare Acanthophyllum (Ap) extract, 1 Kg of dried sample was solved in 5 liter distilled water and manually mixed for 48 h at 30 min hiatuses. Barley grains treated with 5% solution of Acanthophyllum or 5.6% ammonium bicarbonate, simultaneously treated with 1% lactic acid. Consequently, non-treated and chemically treated barley grain steamed for 50 min. Then, steam cooked grains were exposed under an infrared -heated for 55 seconds to attain surface kernel temperatures of 100°C. Finally, passed through the roller mill in a flaker machine and were flaked. Thus, experimental treatments were: 1) Steam- infrared heated -flaked of barley grain, 2) Steam- infrared heated -flaked of barley grain treated with extract of Acanthophyllum and lactic acid, 3) Steam- infrared heated -flaked of barley grain treated with ammonium bicarbonate and lactic acid. This experiment with a 3 × 3 Latin square design were conducted with three rumen-cannulated Holstein cows (average BW: 690± 13, DIM: 96± 9) in three 21-day periods. Productive responses and dry matter intake were evaluated during the last 4 d of each period. Blood sample was collected on day 21 of the experimental period before the morning feeding and 2, 4 and 6 h after morning feeding to evaluate the concentration of serum glucose, albumin, total protein and blood urea nitrogen concentration. Acid insoluble ash as an internal marker was used to measure the apparent digestibility of nutrients. The ruminal pH and NH3-N concentration were continuously measured.
Results and Discussion: Results illustrated that the experimental diets did not affect (P>0.05) on DMI, milk production, FCM and ECM. Milk fat and lactose concentrate were higher in cows fed by the diet containing the steam- infrared heated -flaked of barley grain treated with extract of Acanthophyllum and lactic acid and/ or treated with ammonium bicarbonate and lactic acid treatments than the steam- infrared heated -flaked of barley grain treatment (P < 0.05). Milk total solid, protein and MUN concentrate were increased in response to fed the steam- infrared heated -flaked of barley grain treated with ammonium bicarbonate and lactic acid compared to the control (P < 0.05). Generally, serum BUN concentration was significantly affected by the chemical treating during 2, 4 and 6 h after the morning feeding (P< 0.05). The consuming of steam- infrared heated -flaked of barley grain treated with ammonium bicarbonate and lactic acid resulted in increased total blood protein concentration (at 6 h after the morning feeding) in the cows (P< 0.05). When the chemical treatment was used, the apparent digestibility of dietary DM, CP and starch was increased in the cows consuming these diets (P< 0.05). Ruminal pH and also redoex potential were not affected by treatments and sampling time (P> 0.05). In this study, data showed that cows fed the SIFBLaAb had greater ruminal NH3-N concentration when compared with the other treatments (p< 0.05).
Conclusion: Feeding chemical treated barley grain with 5% extract of Acanthophyllum and/or 5.6% ammonium bicarbonate plus 1% lactic acid did not affect DMI and milk production in dairy cow, but improved the milk composition, with higher milk fat, lactose, protein and total solid. In animals fed chemicallym, treated barley grain the nutrient apparent digestibility, enhanced significantly. The MUN, BUN and ruminal NH3-N concentration increased in cows fed the diet with SIFBLaAb.
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