Effect of a high-concentrate diet on milk components and mammary health in Holstein dairy cows.
In order to evaluate the milk yield, milk quality, and health of dairy cows fed a high-concentrate (HC) diet, eight lactating Holstein dairy cattle were randomly assigned to HC or low-concentrate (LC) diet groups and fed for 50 days, and the auto-control studying before and after treatment with the two diets was used. During the experiment, plasma and milk samples were collected and measured. With regard to milk component, HC feeding led to higher milk production (P < 0.05), but significantly lower milk protein percentage (P < 0.05), milk protein yield (P < 0.05), and milk fat percentage (P < 0.05) throughout the five periods than LC feeding. Milk somatic cell count and N-acetyl-D-glucosaminidase activity (P < 0.01) were higher than those observed under LC feeding. mRNA expression levels of interleukin-8 (IL-8), C-C motif chemokine ligand (CCL5), and lactalbumin alpha (α-LA) were investigated by qPCR and found to be significantly lower (P < 0.01) in cattle fed the HC diet. The amino acid content was analyzed by high performance liquid chromatography (HPLC), and the content of Asp (P < 0.01), Gln (P < 0.01), Ala (P < 0.05), Leu (P < 0.05), Lys (P < 0.05), and Ile (P < 0.01) was significantly lower in the HC group, whereas the content of Arg (P < 0.05) and Phe (P < 0.01) was significantly higher. These results suggest that the HC diet might have an important influence on mammary health. The amino acid content was lower, suggesting that depletion of amino acids, resulting in depleted milk protein, affects milk quality.
Jinshan College of Fujian Agriculture and Forestry University, Cangshan District, Fuzhou City, Fujian Province, China 312498721@qq.com.|Key Laboratory of Traditional Chinese Veterinary Medicine and Animal Health in Fujian Province, Fujian Agriculture and Forestry University, Cangshan District, Fuzhou City, Fujian Province, China 312498721@qq.com.|Beef Cattle Feeding Teaching Experimental Base, Jinshan College of Fujian Agriculture and Forestry University, Baisha Town, Minhou county, Fuzhou City, Fujian Province, China 312498721@qq.com.
Z L
ZL
Xie
Key Laboratory of Traditional Chinese Veterinary Medicine and Animal Health in Fujian Province, Fujian Agriculture and Forestry University, Cangshan District, Fuzhou City, Fujian Province, China.
J
J
Zhang
Beef Cattle Feeding Teaching Experimental Base, Jinshan College of Fujian Agriculture and Forestry University, Baisha Town, Minhou county, Fuzhou City, Fujian Province, China.
D M
DM
Zhang
Beef Cattle Feeding Teaching Experimental Base, Jinshan College of Fujian Agriculture and Forestry University, Baisha Town, Minhou county, Fuzhou City, Fujian Province, China.
J F
JF
Li
Beef Cattle Feeding Teaching Experimental Base, Jinshan College of Fujian Agriculture and Forestry University, Baisha Town, Minhou county, Fuzhou City, Fujian Province, China.
Y H
YH
Lin
D000199:Actins / Q000378:metabolism; D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D002417:Cattle; D018946:Chemokine CCL5 / Q000378:metabolism; D004032:Diet / Q000662:veterinary*; D005260:Female; D016209:Interleukin-8 / Q000378:metabolism; D007768:Lactalbumin / Q000378:metabolism; D007774:Lactation / Q000502:physiology; D008321:Mammary Glands, Animal / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D008892:Milk / Q000378:metabolism / Q000592:standards*; D008894:Milk Proteins / Q000008:administration & dosage*; D011897:Random Allocation; D012417:Rumen / Q000378:metabolism
D000199:Actins; D018946:Chemokine CCL5; D016209:Interleukin-8; D008894:Milk Proteins; D007768:Lactalbumin