The transition period is the most stressful for dairy cows in terms of metabolic rate and characterized by dynamic changes in the hormonal profile, loss of appetite, negative energy balance, nutrient and vitamin deficiencies, compromised immunity and oxidative stress. The aim of the research was to balance the increase in cows’ productivity and the consumption of nutrients from the feed during the transition period through the use of energy feed additives (EFS), high protein feed concentrate (PFC) in combination with biologically active (BA) substances. Thirty-six dairy cows of black-motley breed were divided into 3 groups: (1) The main diet (G0, n = 12), not supplemented with additives, (2) additive 1 (G1; supplemented with 0.5 kg EFS / cow per day, n = 12), (3) additive 2 (G2; supplemented with 0.5 kg EFS; 0.5 kg PFC and 0.06 kg BA / cow per day, n = 12). The experimental part of the feeding lasted for 20 days before calving and the first 100 days after calving (DPP). Blood samples were collected during the first and the third months after calving. The biochemical analyzer was used to measure blood serum components. The milk yield was recorded monthly throughout lactation. BCS losses from 7 days prior to calving to 28 DPP were -0.29 for Gr2, -0.42 for Gr1 and -0.60 for Gr0. Feeding with additive 2 (Gr2) increased milk yield (p≤0.05) in the first 100 DPPs and (p≤0.001) 305 DPPs compared to G0. The number of samples with SCC ≥ 500 000 / ml. per 100 DPP was 51% in the Gr0 group, 27% in Gr1, 25% in Gr2. Also, microbiological control showed an excess of Bacterial cells in the milk of cows from group G0, which correlates with SCC indicators. Cows from Gr2had a lower content of ketone bodies (P≥0.001) and higher (P≥0.001) antioxidant activity of blood serum compared to Gr0. Cows from Gr2 had an increase in ALT activity by1.4 times (P <0.05) from the first to the third months after calving.
Kluyveromyces marxianus yeast is often isolated from dairy products and used as probiotic agents in food. As a producer-yeast they must be genetically stable, have simple nutrient requirements, be effective in hostile conditions, grow on inexpensive nutrient media and be easy to store and distribute. Nineteen strains of K. marxianus isolated from natural biotopes were tested for their ability to grow on various carbon sources. For this, the YPD medium (1% yeast extract, 2% peptone, 2% dextrose, pH 5.5) was used with the addition of 20 g/L of one of the following carbon sources: glucose, sucrose, lactose, maltose, mannitol, arabinose, xylose, and galactose. The cultivation was carried out for 1–3 days. All isolates were also tested for their ability to grow in YPD broth at different temperatures (4, 27, 37, 40, 42, 46 and 48 °C) and pH (5; 3 and 2). K. marxianus strains showed widespread use of the substrate and high resistance to elevated incubation temperatures. All tested strains grew at 27 and 37 °C and one strain grew at 46 °C. None of the strains showed active growth at pH 2 and all cultures grew actively at pH 3. At the same time five strains showed growth at pH 5.0. All strains fermented galactose, 16 - xylose, 9 - glucose, 7 - lactose, 12 - maltose, 11 - arabinose, 5 - sucrose, 13 - mannitol. It should be noted that all strains in this study have showed fully restored growth after 2 hours’ incubation at pH 2. It indicates that they could survive when passing through the gastric passage into the intestine. These properties make the use of K. marxianus and its metabolites indispensable in agriculture as a feed additive. This work was supported by the Ministry of Science and Higher Education of Russia.
Мастит-распространенное инфекционное заболевание молочного скота, наносящее существенный экономический ущерб животноводству и влияющее на качество молочной продукции. Основной возбудитель мастита крупного рогатого скота (КРС)-золотистый стафилококк (Staphylococcus aureus). Заражение молочной железы S. aureus остается серьезной проблемой для всех стран мира. Болезнетворные свойства S. aureus и устойчивость в организме хозяина определяются набором токсинов. Микроорганизм продуцирует патогенные факторы, которые оказывают значительно влияние на течение заболевания. В настоящее время не существует эффективного способа борьбы с маститом, поэтому исследования иммунного статуса коров по отношению к энтеротоксинам стафилококка актуальны. Цель нашей работы заключалась в выявлении и определении титров антител, специфичных к наиболее распространенным энтеротоксинам стафилококков A, B, C, D, E, G, H, I и TSST, в сыворотке крови и молозиве коров (Bos taurus taurus). Объектом исследований были животные голштинизированной черно-пестрой породы второй лактации (n = 47, 2016 год), которые находились на беспривязном содержании в хозяйстве Калужской области и 2 раза в год подвергались иммунизации вакциной Mastivak («Laboratorios Ovejero S.A.», Испания). Кровь отбирали из хвостовой вены (с последующим центрифугированием для осаждения форменных элементов), молозиво и молоко-непосредственно после доения из всех долей вымени в стерильные флаконы с соблюдением правил асептики. Наличие и титр Ig к энтеротоксинам A, B, C, D, E, G, H, I и TSST стафилококков оценивали методом непрямого иммуноферментного анализа. В 53,19 % образцов сывороток детектировались антитела класса G (IgG), специфичные к SEH. Антитела к TSST обнаружены в 4,26 % образцов, при этом их титр был самым низким по сравнению с антителами к другим энтеротоксинам. Антитела к SEB, SED, SEE, SEG, SEI и TSST вывили соответственно у 10,64; 23,47; 31,91; 29,78; 34,04 и 4,26 % животных. Анализ секретов молочной железы показал наличия в молозиве IgA к SEH, SEG и SEI. IgA к SEA, SEB, SEC, SED, SEE, TSST обнаружены не были. В молоке антитела к энтеротоксинам не выявляли. Таким образом, в сыворотке крови и молозиве клинически здоровых коров голштинизированной черно-пестрой породы установлено наличие антител к стафилококковым энтеротоксинам SEA, SEB, SEC, SED, SEE, SEG, SEH, SEI и TSST, то есть животные могли иметь контакт со стафилококками, продуцирующими такие типы токсинов.
The research was done on the herd (n = 3000) of cows of black-motley breed with an admixture of Holstein. At the first stage, the diagnosis was carried out by using the Keno test. There were selected 148 (4.9%) cow, which had of subclinical mastitis. For treatment, there were used the schemes tried and tested in the farm: (1) nisin, polymexin B, ketoprofen, methyl salicylate; (2) nisin, polymexin B, ketoprofen, ceftiofur; (3) amoxicillin, ketoprofen, methyl salicylate, prednisone. Before it, the allocation of pathogens was not carried out. After treatment the number of repeated cases of the disease reached 44.6%, which indicated the ineffectiveness of the treatment regimens used. At the second stage, samples of milk, nasal and vaginal mucus were taken from animals with a relapse of mastitis. Different pathogens were used to isolate pathogens (Staphylococcus aureus, Escherichia coli, Shigella spp., Enterococcus spp., Ps. aeruginosa). The extracted isolates were identified based on the cultural and biochemical properties. The results were interpreted on the recommendation of EUCAST. Of all the animals examined, they simultaneously detected in milk 3 pathogens in 37.8%, 2 pathogens in 40.9%, and only one pathogen was isolated in 21.3%. Moreover, S. aureus (84.8%), Ps. aeruginosa (62.1%), Enterococcus spp. (34.8%) was found in smears from the vagina. The sensitivity of the selected pathogens to antimicrobials showed that 73% of S. aureus strains were resistant to ≥6 antibiotics, 47% E. coli to ≥7, 34% Shigella spp. to ≥4 and 21% Ps. aeruginosa to ≥4. The use of antibiotics of different groups without isolating the pathogen and determining its sensitivity leads to the appearance of multiresistant strains of bacteria and culling animals from the herd. This work was supported by the Ministry of Science and Higher Education of Russia (AAAA-A18-118021590136-7) and the Russian Science Foundation (project 20-16-00106).
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