نوع مقاله : مقاله کامل علمی- پژوهشی
نویسندگان
1 دانشآموخته دکتری تخصصی، گروه علوم دامی، دانشکده کشاورزی، دانشگاه صنعتی اصفهان
2 استادیار گروه علوم دامی، دانشکده علوم و مهندسی کشاورزی، پردیس کشاورزی و منابع طبیعی دانشگاه تهران، کرج
3 دانشیار، گروه علوم دامی، پردیس کشاورزی و منابع طبیعی کرج، دانشگاه تهران، کرج، ایران.
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and Objective: The growing world population has increased the demand for animal products, and with limited feed resources, the livestock industry faces significant challenges. Using by-products from the food industry in ruminant nutrition can be a solution to reduce environmental problems and feed costs. Vinasse (concentrated molasses solution) is a by-product of the bioethanol industry produced through molasses fermentation. This substance contains crude protein (mainly non-protein nitrogen), ash (especially potassium), glycerol, and dead Saccharomyces cerevisiae yeast, which has prebiotic properties. Studies have shown that using vinasse in ruminant nutrition leads to increased feed intake, improved feed conversion ratio, enhanced dry matter digestibility, increased daily weight gain, and higher milk production. Heat stress is one of the major challenges in dairy cattle farming and causes an imbalance between metabolic heat production and its dissipation to the environment. Under heat stress conditions, potassium is significantly excreted through sweat. Given the high concentration of potassium in vinasse, the hypothesis of this study is that adding different levels of vinasse to the diet of lactating cows under heat stress could improve ruminal metabolites and blood parameters by replacing lost potassium and improving the ruminal environment.
Materials and Methods: This experiment was conducted using 84 lactating cows (28 cows per treatment) with an average of 155 ± 25 days in milk, milk production of 32 ± 3 liters per day, and parity of 2.4 ± 0.1 in a completely randomized design. Animals were randomly assigned to one of three treatments: 1) control (diet without vinasse), 2) five percent (1.1 kg), and 3) 10 percent (2.2 kg) vinasse based on dry matter. The study was conducted in summer with an average temperature-humidity index of 75.1, and the period lasted 25 days (15 days adaptation and 10 days sampling). To investigate the effect of experimental diets on blood parameters of dairy cows, blood was collected from the tail vein on day 22 of the experiment, about 4 hours after morning feeding. Also, on day 25, rumen fluid was sampled using a vacuum pump 3 to 4 hours after the morning feeding.
Results: The results showed that plasma glucose concentration decreased linearly (P=0.01), but protein concentration increased linearly (P=0.02) with increasing vinasse in the diet. Acetic acid in rumen fluid increased linearly with the addition of vinasse to the diet (P=0.01). Valeric acid was also linearly affected by experimental treatments and decreased with the addition of vinasse to the diet. Rumen fluid pH (P=0.08) and isovaleric acid (P=0.06) showed a tendency toward significance, with the highest values observed for 10 percent vinasse and control treatments, respectively.
Conclusion: The results of this study showed that using vinasse up to 5 percent of dry matter in the diet of dairy cows under heat stress can help reduce the negative effects of heat stress by improving blood metabolites (increasing total protein) and ruminal metabolites (increasing acetic acid and tendency to increase rumen pH).
کلیدواژهها [English]
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