عوامل حیوانی، شرایط بدنی، عملکرد تولید شیر و کیفیت چرای گاوهای شیری: یک مطالعه مروری
Subject Areas : Camel
1 - Centro de Investigaciones Agrarias de Mabegondo, INGACAL, Apdo, 10-15080, La Coruna, Spain
Keywords: عملکرد, وزن بدن, امتیاز شرایط بدنی, کیفیت شیر, توازن انرژی, تولید شیر بالقوه,
Abstract :
مبنا و اساس این مطالعه مروری در نظر گرفتن نقشی است که عوامل حیوانی (تولید شیر بالقوه، وزن بدن، امتیاز شرایط بدنی، وضعیت شیردهی، شکم زایش و باروری) در عملکرد تولید شیر (با در نظر گرفتن توازن انرژی و عملکرد شکمبه در طی منحنی کامل شیردهی حیوانات) و کیفیت شیر (محتوای پروتئین شیر، محتوای چربی شیر، محتوای لاکتوز شیر، ویتامینها، مواد معدنی، ایمنوگلوبولینها، سلولهای شیر، باکتریهای بیماریزا و بازدارندهها) گاوهای شیری در حال چرا ایفا میکنند. البته نرخ جایگزینی و پاسخ تولید شیر در مرتع حیوانات در شرایط مصرف برنامههای مکملسازی مختلف باید در نظر گرفته شود. تمامی این عوامل، در جهت دستیابی به تولید شیر بالا در حیوانات، به مدیریت مرتع به عنوان عامل کلیدی بقای سیستمهای شیری چرا توجه دارند. همچنین مدیریت مرتع به منظور حفظ مصرف ماده خشک مرتعی بالا در چمنزارهای با کیفیت علوفه گرامینه بالا (دارای سطوح بالای پروتئین خام، کربوهیدراتهای محلول در آب و قابلیت هضم ماده آلی در مرتع ولی دارای سطوح پایین الیاف نامحلول در محلول پاک کننده اسیدی و خنثی) حائز اهمیت است. این نوع چمنزارها در تمامی طول فصل چرا نیازهای گاو را در تمامی زمانها و در طی طول دوره شیردهی برآورده مینمایند. همچنین ضروری است تا استفاده از مکملسازی مرتع بتواند سطح تولید شیر را در حد مطلوب حفظ نماید. به طور طبیعی در نقطه اوج دوره شیردهی یعنی زمانی که گاوها به طور کلی در وضعیت توازن منفی انرژی هستند فراهم نمودن مواد سیلو شده یا کنسانتره میتواند به بهبود این شرایط کمک کند. به موجب این امر، باید به دنبال دستیابی به نرخ تبدیل بهینه علوفه گرامینه به شیر به صورت رقابتی و سودآور بود. برای نیل به این هدف سیستمهای تولید شیر مبتنی بر مرتع در بیشتر مناطق معتدله در سرتاسر جهان ایجاد شده است که تأکید آنها بر افزایش قیمت شیر و افزایش درآمد دامداران در نواحی مرطوبی نظیر گالیسیا (در شمال غربی اسپانیا) است. در این صورت بهبود کمیت و کیفیت شیر تولیدی به صنایع شیری انتقال مییابد.
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