Evaluation of Udder Cisterns and Effects on Milk Yield of Dairy Ewes

• Published in: Journal of dairy science Vol. 91; no. 12; pp. 4622 - 4629
• Main Authors: Rovai, M, Caja, G, Such, X
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.12.2008; American Dairy Science Association; Am Dairy Sci Assoc; Elsevier
• Subjects: alveolar milk; animal morphology; Animal productions; Animals; Biological and medical sciences; breed differences; cisternal milk; dairy animals; dairy sheep; Dairying; ewes; Female; Food industries; Fundamental and applied biological sciences. Psychology; Hormone Antagonists - pharmacology; hormone receptors; Lactation - drug effects; Lactation - physiology; lactation stage; Mammary Glands, Animal - anatomy & histology; Mammary Glands, Animal - diagnostic imaging; Mammary Glands, Animal - physiology; Milk - chemistry; Milk - cytology; Milk - secretion; Milk and cheese industries. Ice creams; milk ejection; milk yield; milking; milking ability; milking machines; oxytocin; Sheep - anatomy & histology; Sheep - physiology; sheep breeds; Species Specificity; teats; Terrestrial animal productions; udder alveoli; udder cisterns; udders; Ultrasonography; Vasotocin - analogs & derivatives; Vasotocin - pharmacology; Vertebrates; oxytocin; cisternal milk; dairy sheep; milking ability; Ability; Evaluation; Dairy animal; Farming animal; Oxytocin; Dairy product; Milk production; Vertebrata; Meat animals; Mammalia; Dairy industry; Milking; Sheep; Artiodactyla; Mammary gland; Ungulata; Milk
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.2008-1298

Nine Manchega (0.94 L/d) and 10 Lacaune (2.07 L/d) ewes at the same stage of lactation (90 d in milk) were used to study the interbreed differences in milk yield, mammary morphological traits, and machine-milking ability. Udder traits were measured after 6h of udder filling before the start of the experiment. Cisternal area (by ultrasonography), cisternal milk (by teat cannula drainage), and alveolar milk (by machine milking after an intravenous oxytocin injection) were randomly measured 8h after milking for 2 wk consecutively either with an intravenous injection of an oxytocin receptor blocking agent (atosiban, AT) or without (control, C) to avoid the occurrence of milk letdown before milking. Lacaune ewes had greater udder depth (22.5±0.9 vs. 19.6±0.9cm) and cistern height (27.1±3.8 vs. 15.6±3.5mm), whereas Manchega ewes had longer (42.7±1.5 vs. 32.7±1.5mm) and wider teats (17.4±0.5 vs. 13.9±0.5mm). Values per half udder for Manchega and Lacaune ewes differed in cisternal area (12.8±0.7 and 23.7±0.6cm2) and cisternal milk (120±0.6 and 269±0.5mL), but not in alveolar milk (95±0.5 and 102±0.4mL), respectively. Cisternal area and cisternal milk were positively correlated (r=0.79). Ratios between cisternal and alveolar milk were 56:44 and 73:27 for Manchega and Lacaune ewes, respectively. Cisternal milk volumes obtained with the AT or C treatment were similar in Manchega (111±10 vs. 122±8mL) but differed in Lacaune ewes (239±8 vs. 299±8mL), respectively. Consequently, alveolar milk with AT vs. C was similar in Manchega (104±8 vs. 86±7mL) but different in Lacaune ewes (115±7 vs. 89±7mL). Results of this experiment confirm the need for the use of an oxytocin-blocking agent for accurate evaluation of milk contained in the udder of dairy ewes. Moreover, despite the differences in daily milk yield, alveolar milk did not vary between breeds, emphasizing the role of the cisternal more than the alveolar compartment for maximizing daily milk secretion in dairy sheep.