نوع مقاله : مقاله پژوهشی
نویسندگان
1 بخش تحقیقات تغذیه و فیزیولوژی دام، موسسه تحقیقات علوم دامی کشور، سازمان تحقیقات، آموزش و ترویج کشاورزی
2 گروه علوم دامی، دانشگاه آزاد اسلامی واحد خوراسگان (اصفهان)
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Effects of nano-encapsulated plant stimulants (based on Thyme, Oregano and Ajwain) on the performance of Holstein dairy calves
Abstract
Background and Objectives: Stimulating dairy calves to consume more feed results faster transition from milk to solid feed. Many medicinal plants improve the taste of feed, and by increasing feed consumption, they improve the growth performance and production of animals. This study aimd to determine the effects of nano-encapsulated plant stimulants (NPS) based on thyme, oregano and ajwain on the growth performance, blood metabolites and structural growth of calves.
Material and methods: Individually housed calves (n=40; body weight=37.6±0.79 kg) were randomly assigned in a completely randomized design for 68- days (4 to 72 days, n=10 calves per treatment: 5 males and 5 females) to one of the following four treatments: 1) control diet- starter, 2) starter + 0.1% NPS), 3) starter + 0.2% NPS and 4) starter + 0.3% NPS. The calves were weighed at birth and it was repeated at 10, 30, 60 and 72 (weaning) days. Blood was sampled 2 hours after the morning milk on the 56th day of the experiment, and the concentration of triglyceride, cholesterol, total protein and immunoglobulin G was determined. Also, the structural growth of calves was measured using standard measuring tapes on days 30 and 60 of experimen.
Results: The results showed that at the time of weaning, the calves fed 0.3 % NPS in the diets, had the highest average body weight and it was 8.6% more than the control group (P=0.04), and linearly increased (P=0.02) as the level of NPS increased in the diets. The average daily gains of calve were higher in the calves fed rations containing 0.3% NPS than other groups (P<0.05), and linearly increased (P<0.01) as the level of NSP increased in the diets. Daily dry matter intake was not affected by different levels of NSP in the diets. Feed conversion ratio ranged from 1.80 to 1.98 in the experimental groups (P<0.01), and responded linearly (P = 0.05) as the level of NPS increased in the diets. The concentration of cholesterol and total protein in the blood plasma, were highest (P<0.05) in calves fed 0.2% and 0.1% NPS in the diets respectively, while the concentration of triglyceride and immunoglobulin G was not affected by different levels of NPS in the diets. No significant difference was observed in the average structural growth of calves such as body length, height, body barrel and heart girth between calves of different groups at the age of 30, 60 and 72 days. However, heart girth tended to increase linearly (P=0.08) at day 30, and increase linearly (P=0.04) at day 72 as the level of NPS increased in the diets.
Conclusion: It was concluded that, the use of NPS in the starter of dairy calves did not affect the dry matter intake, but by increasing the level of NPS in the diets, the average daily gain increased linearly and the feed conversion ratio improved linearly.
کلیدواژه‌ها [English]
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