کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
2439902 | 1108107 | 2008 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Effect of Milking Interval on Milk Secretion and Mammary Tight Junction Permeability in Dairy Ewes
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
علوم کشاورزی و بیولوژیک
علوم دامی و جانورشناسی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Twenty-four lactating ewes (Manchega, n = 12; Lacaune, n = 12) in mid lactation were used to assess the short-term effects of different machine milking intervals (4, 8, 12, 16, 20, and 24Â h) on milk yield, milk composition, and tight junction (TJ) permeability of mammary epithelia. Milk samples were analyzed for chemical composition, somatic cell count (SCC), and plasmin activity. Plasma lactose, and milk Na and K concentrations were used as indicators of TJ permeability. Milk accumulated linearly for up to 24Â h, showing a different rate according to the milk yield of the breed (Manchega, 38Â mL/h; Lacaune, 87Â mL/h). Milking interval affected milk fat content, which decreased markedly from 4 to 24Â h in both breeds, but no differences were observed in milk protein content. The milk contents of casein, true protein, lactose, and total solids also varied according to milking interval. Values of SCC did not vary by breed (175Â ÃÂ 103Â cells/mL, on average), showing the lowest log10 values for the 4-and 24-h milking intervals in both breeds. Plasmin activity in milk increased with milking interval until 20Â h of udder filling in both breeds, and was poorly but positively correlated with SCC content (r = 0.39). Plasma lactose increased dramatically after 20Â h of milk accumulation, indicating enhanced permeability of mammary TJ. As a result, an increase in Na concentration and in the Na:K ratio, and a decrease in K concentration, were observed in the milk of Manchega ewes. On the contrary, no differences in Na and K concentrations in milk were detected in Lacaune ewes. In conclusion, our results proved that Manchega and Lacaune dairy sheep could maintain high rates of milk secretion during extended milking intervals in the short term, with no effects on udder health and few negative effects on milk yield. Increased TJ permeability, caused by the effect of udder filling, induced changes in milk composition that were more marked in Manchega than in Lacaune ewes.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Dairy Science - Volume 91, Issue 7, July 2008, Pages 2610-2619
Journal: Journal of Dairy Science - Volume 91, Issue 7, July 2008, Pages 2610-2619
نویسندگان
V. Castillo, X. Such, G. Caja, R. Casals, E. Albanell, A.A.K. Salama,