Udder Cisterns Research Articles

Udder morphology and milk yield of East Friesian sheep

Linear scores and measures of both udder and teat shape and size (thirteen traits) were assessed in 83 ewes of Improved Valachian breed (IV) and in crossbreds with East Friesian breed (EF 25% or EF 50%). At the same time, cistern measures and cross-section areas (fourteen traits) as well as milk yield and milkability were scanned using ultrasound technique or measured in the same individuals (130 measurements in each trait). Crossbreds with EF 50% had the largest udders in terms of depth, width, and height, as determined by either a nine-point linear score or exact measurements. Additionally, these crossbreds had teats that were more horizontally placed and the most appropriate udder attachment and shape. more horizontally and most appropriate udder attachment and shape. Ultrasound scans revealed that the areas of both the left and right udder cisterns scanned by ultrasound were the highest in EF 50% crosses. Overall cistern cross-section areas scanned from the side were 2934.6 mm2 in IV, 2932.6 mm2 in crosses of EF 25% and 3559.4 mm2 in crosses of EF 50% (P<0.05). Crossbreds of EF 50% had more appropriate machine milked milk and total milk yield (311.1 and 424.7 ml) than purebred IV (231.8 and 336.1 ml; P>0.05). On average, the proportion of machine-stripped milk was 33.2%, and non-significant influence of genotype was shown. Furthermore, all traits under study showed non significant differences between crosses of EF 25% and 50%.

Ultrasonographic, endoscopic and radiographic examinations of the dromedary mammary glands and teats

The aim of the present study was to examine the mammary gland of dromedary camels using ultrasonography, endoscopy and radiography. These techniques are easy to perform in the field and feasible to diagnose pathological conditions of the mammary gland. Udders of 49 slaughtered and 26 adult dromedary camels submitted for necropsy were used for the examinations. Additionally, 11 lactating female dromedary camels were selected for the ultrasonographic udder examination. The transition from the milk ducts into the udder cistern, the teat cistern and the teat canals were examined in individual udders. Teat cistern length, teat end width, teat wall thickness, teat cistern width and middle cistern wall thickness were measured using ultrasonography. The measurements resulted in mean values of the teat cistern length of 37.3 mm, the teat end width of 2.0 mm, the teat wall thickness of 4.4 mm, the teat cistern width of 8.2 mm and the cistern wall thickness of 3.5 mm. The teat wall was differentiated into three layers, a hyperechoic outer layer, a hypoechoic middle layer and a hyperechoic inner layer. The mid cistern wall was hyperechoic. Endoscopic examination is an easy to perform and practicable method for examining the inner structures of the teats of dead animals; however, the feasibility has not been shown in lactating animals yet. Ring-like folds were present in the teat cistern, which protruded horizontally into the lumen. It was also possible to visualize the branchlike transition of the teat cistern into the larger milk ducts. Radiographic examination using barium sulfate contrast medium showed that the teat cistern ends in a network of initially wide but branching and narrowing milk ducts. The two teat canals and cisterns are completely independent of each other and there is no communication between the glandular tissue of the two canals and cisterns.

Kilis Keçilerinde Süt Verimi ve Meme Sarkıklığı Arasındaki İlişkiler

Bu çalışma; Kilis keçilerinin süt verimi ile meme sarkıklığı arasında herhangi bir ilişki olup olmadığının belirlenmesi için yapılmıştır. Çalışma, Kilis’in Polateli ilçesinde bir işletmede yetiştirilen 73 baş Kilis keçisi üzerinde yürütülmüştür. Bu amaçla keçilerden Meme Üst Yüksekliği (MÜY), Sarnıç Derinliği (SD), Meme Derinliği (MD), Meme Başları Arası Mesafe (MBAM), Meme Alt Yüksekliği (MAY) ve Meme Başı Yüksekliği (MBY) gibi bazı meme ölçüleri alınmış ve keçilerin bir günlük süt verimleri (GSV) tespit edilmiştir. Bu meme ölçülerine ait en küçük kareler ortalamaları sırasıyla; 47.66±0.36 cm, 21.35±0.58 cm, 15.53±0.47 cm, 21.59±0.57 cm, 26.31±0.59 cm ve 23.67±0.60 cm olarak belirlenmiştir. GSV ise 687.09±32.37 g olarak hesaplanmıştır. Keçinin yaşı bu özelliklerden sadece MÜY üzerine etkiliyken, doğum tipinin ise MÜY ve MD özelliklerini etkilediği belirlenmiştir (P

Improving parlor efficiency in block calving pasture-based dairy systems through the application of a fixed milking time determined by daily milk yield and milking frequency

Adjusting end-of-milking criteria, in particular applying a maximum milking time determined by expected milk yield at an individual milking session, is one strategy to optimize parlor efficiency. However, this strategy can be difficult to apply practically on farm due to large differences in session milk yield, driven by milking interval, which affects milking routines and can be limited by in-parlor technology. The objective of this study was to test the hypothesis that a single fixed milking time (duration) could be applied at all milking sessions without compromising milk production or udder health for a range of milking intervals. To test the hypothesis, 4 experimental herds were established: (1) herd milked twice a day (TAD) using a 10- and 14-h interval, (2) herd milked TAD using an 8- and 16-h interval, (3) herd milked 3 times in 2 d using a 10-19-19-h interval, and (4) herd milked once a day (OAD). Herds consisted of 40 cows each, and were established for two 6-wk experimental periods, one in peak lactation and the other in mid-late lactation. Within each herd, half the cows had an end-of-milking criterion of 0.35 kg/min (Flow), and the other half had milking ended after a fixed period of time (FixedT) based on the average milking session yield, the daily milk yield divided by average number of milkings per day, irrespective of milking interval. We found no differences in daily milk yield between end-of-milking criteria due to residual milk from one milking likely increasing the proportion of milk in the udder cistern at the next milking session for the FixedT treatment. However, fat yield was compromised when the percentage of the herd with a truncated milking exceeded an estimated 33% at a milking session, which occurred in the TAD 8-16 herd due to the divergence from the average milking interval (in the case of TAD, 12-12 h). Applying a fixed milking time had no detrimental effects on udder health, except in the OAD herd in mid-late lactation, which had both a higher cell count and new intramammary infection rate. This warrants further investigation, although the majority of cultured bacteria were coagulase-negative staphylococci (CNS). Consequently, we conclude that, in general, with appropriate monitoring (e.g., weekly inspection) to ensure the proportion of the herd with truncated milkings does not exceed 33%, farmers in pasture-based dairy systems can use a fixed milking time to improve parlor efficiency.

Mammary Cistern Size during the Dry Period in Healthy Dairy Cows: A Preliminary Study for an Ultrasonographic Evaluation

Simple SummaryThe dry period is a crucial moment for dairy cows since the udder may develop pathological conditions that could influence the next lactation. We propose a preliminary study for the ultrasonographic evaluation of the udder cistern during the dry period in healthy dairy cows. All four udder cisterns were evaluated and measured by ultrasound at different times. Our results showed a statistically significant negative linear correlation between the time and udder cistern size. In addition, this study showed that the udder cistern size decreased throughout the whole dry period and started to increase at the beginning of the next lactation.We evaluated the udder cistern (UC) size during the dry period using ultrasound. Forty healthy quarters were evaluated in both the longitudinal and cross-section of the UC. Quarters were evaluated at the drying-off (T0) and 24 h later (T1), then regularly until the end of the dry period (T7–T58), during the colostrum production phase (TCPP) and at 7 days in milking (T7PP). The Spearman test was applied to find the correlation between the ultrasonographic UC size (UUCS) assessment and time. The Friedman test and Dunn’s test for multiple comparisons as a post-hoc test were performed to compare the forequarter and hindquarter cross-sections (FQCSs and HQCSs, respectively) and the forequarter and hindquarter longitudinal sections (FQLSs and HQLSs, respectively) at T0 vs. T58 vs. TCPP vs. T7PP. A total of 440 images were evaluated. A negative linear correlation between time and FQCS and FQLS (r = −0.95; p < 0.0004) and between time and HQCS and HQLS (r = −0.90; p < 0.002) was found. The UUCS decreased throughout the dry period, starting to increase at the beginning of the next lactation. Measuring the UUCS provides useful information for monitoring the dry period.

Measurement of the Mammary Gland Cistern of Dairy Ewes

At the 3rd and 5th month of lactation, using the ALOKA‑250 ultrasonograph with a 3.5 MHz probe, the udder cistern size of the breed Improved Valachian (IV) and the crossbreed IV x Lacaune (IV x LC) was surveyed. Using the method from side 72 ewes were measured, in which the probe was placed in the inguinal‑abdominal fold. Variance analysis was used to evaluate the obtained data (length, width and udder cistern area), taking into account the effect of the genotype, stage of lactation and lactation order. The average length, width and area of the left udder cistern (LUC) was 80.72 mm; 33.53 mm and 1907 mm2; for the right udder cistern (RUC) 79.44 mm; 33.01 mm and 1851 mm2. The genotype had a statistically significant effect on the LUC as well as the RUC size (P &lt; 0.05 to 0.001). The LUC area of the IV x LC ewes was 32.7% bigger than at IV (2175 mm2 and 1639 mm2, respectively), and the difference of the RUC was up to 51% in favour of the crossbreed (2227 mm2 and 1475 mm2, respectively). This may be due to laterality, the natural asymmetry found in many mammals. The variability in the observed variables of the left and right udder cisterns was greater in crossbreeds than in the purebred IV ewes.

Minimal-invasive tissue sampling at the bovine udder

In some cases, classical diagnostic procedures of bovine mastitis, including adspectation, palpation, and examination of milk samples, are of limited reliability, such that histological examination of udder tissue would be a useful addition. The study aimed to identify localizations for tissue sampling and to validate the biopsy technique. In the present study, sonographic examinations on bovine udders (n = 16) were performed, to identify ideal localizations for tissue sampling, which were tested in slaughterhouse organs (n = 10) and verified in udders of lactating cows (n = 16). Ideal localizations for tissue sampling, avoiding puncturing of blood vessels, were sonographically identified in the area of the udder cistern. Tissue sampling in lactating cows proved to be free of complications in 73 % of cases and all tissue specimens obtained were suitable for histology. Tissue sampling by biopsy for microbiological and histopathological examinations supplements common procedures in the diagnostics of mastitis in the dairy cow and, if performed in the area of the udder cistern, can be conducted without sonographical control under field conditions.

The effect of sampling technique on PCR-based bacteriological results of bovine milk samples

The aim of the study was to evaluate the effect of sampling technique on the microbiological results of bovine milk samples using multiplex real-time PCR. Comparison was made between a technique where the milk sample was taken directly from the udder cistern of the udder quarter using a needle and vacuum tube and conventional sampling. The effect of different cycle threshold (Ct) cutoff limits on the results was also tested to estimate the amount of amplified DNA in the samples. A total of 113 quarters from 53 cows were tested pairwise using both techniques, and each sample was studied with real-time PCR. Sampling from the udder cistern reduced the number of species per sample compared with conventional sampling. In conventional samples, the number of positive Staphylococcus spp. results was over twice that of samples taken with the needle technique, indicating that most of the Staphylococcus spp. originated from the teat or environmental sources. The Ct values also showed that Staphylococcus spp. were present in most samples only in low numbers. Routine use of multiplex real-time PCR in mastitis diagnostics could benefit from critical evaluation of positive Staphylococcus spp. results with Ct values between 34.0 and 37.0. Our results emphasize the importance of a careful aseptic milk sampling technique and a microbiologically positive result for a milk sample should not be automatically interpreted as an intramammary infection or mastitis.

Effect of milking interval on milk partitioning between udder compartments, milk yield and milk composition in Maghrebi dairy camels

Ten multiparous Maghrebi she-camels (Camelus dromedarius L.) were used to study the effects of 6 milking intervals (4, 8, 12, 16, 20 and 24h) at mid-late lactation (281±41 days in milk) on milk partitioning between udder compartments, milk yield and milk composition. Camels were kept in loose stalls, fed forage and concentrate, and hand milked twice-daily. Average milk yield during the experiment was 4.2±0.3l/day. Cisternal and alveolar milk were obtained by sequential milking, before and after inducing milk let-down with exogenous oxytocin, respectively. Udder cisterns volumes were measured by real-time ultrasonography before and after milk let-down. Backflow of milk from the cistern to the alveoli as consequence of udder elastic recoil was measured at 12-h milk interval by delaying milking for 90min after inducing milk let-down with oxytocin. On average, 44% of total milk volume was stored in the front udder quarters and 56% was stored in the rear udder quarters. Alveolar compartments accounted for 92% of milk volume and cisternal compartment for 8%. The volume of milk in the cistern (132±30ml) did not vary with increase in milking interval. Udder cisterns were visible by ultrasonography as small cavities that were dramatically engorged with milk after milk let-down. Milk secretion rate decreased linearly (ml/h=168.3−3.2 x; r2=0.90, P<0.05) upon increase of milking interval from 4 to 24h (from 168±28 to 105±10ml/h). Fat content in alveolar milk was 3.26±0.10% and protein content in alveolar milk was 3.39±0.08% .The content of fat and protein in the alveoli were greater across all milking intervals (P<0.05) than those measured in cisternal milk (2.22±0.10% for milk fat and 2.96±0.05% for milk protein). The concentration of fat and protein in milk decreased linearly with increase in milking interval (r2=0.98; P<0.05), except in the case of milk protein in cisternal milk, which did not change significantly with advancing milking intervals. Lactose concentration was steady across all milking intervals. A dramatic drop of milk secretion (62%) was observed when milking was delayed 90min after induced milk let-down, indicating the necessity of early milking after milk let-down. In conclusion, selection for large-cistern udders and twice-daily milking are recommended for improving the machine milking ability of this breed in order to increase its use for milk production.

Paramètres génétiques de la taille des citernes de lait chez les brebis diagnostiqués par échographie parmi les races: improved Valachian, Tsigai, Lacaune et leurs croisements

La taille de la citerne de lait a été diagnostiquée chez les brebis en utilisant l’échographie et la sonde linéaire de 3,5 MHz de deux façons: La méthode de côté et celle de bas. L’échographie a été faite à partir de chaque scan et ensuite la taille du réservoir à gauche et à droite a été mesurée en utilisant la technique numérique. Les deux citernes ont été scannées environ 12 heures après la dernière traite. L’espace gauche de la citerne (ALC1; 1.933.35 mm2) et celui de droite (ARC1; 1.970.72 mm2), détectés par la méthode de côté, ont été diagnostiqués à plusieurs reprises chez 378 brebis (pendant l’allaitement ainsi qu’entre lactations); un total de 1198 mesures ont été effectuées. L’espace gauche de la citerne (ALC2; 2.137.67 mm2) et de droite (ARC2; 2.171.12 mm2), détectés par la méthode du bas, ont également été diagnostiqués à plusieurs reprises, notamment chez 265 brebis; 753 mesures ont été réalisées au total. La somme des deux zones de section transversale détectées par la méthode de côté (SLRC1) était de 3904.07 mm2, et celle détectée par la méthode de fond (SLRC2) était 4308.77 mm2. Les données primaires ont été traitées en utilisant la méthodologie REML et le modèle animal trait multiple, en utilisant des programmes comme REMLF90 et VCE 4.0. En plus de l’effet génétique additif aléatoire des animaux et l’effet permanent des brebis, les modèles incluent l’année de contrôle comme facteur fixe (7 ou 5 niveaux), un stade de lactation (4 niveaux), un groupe de race (9 niveaux) et la parité (3 niveaux). Nous avons trouvé des valeurs plus élevées de h2 pour les paramètres diagnostiqués par la méthode du bas. Le coefficient d’héritabilité pour ALC1 et ALC2 était de 0.07 et 0.18, respectivement; pour ARC1 et ARC2 de 0.17 et 0.2, resp.; et pour SLRC1 et SLRC2 de 0.12 et 0.17, respectivement. Les corrélations génétiques entre ARC1 et ARC1 ou ARC2 et ARC2 étaient élevées (rg= 0.73 ou 0.910). De même, les corrélations entre la taille de la citerne gauche et/ou droite, et la taille totale des deux citernes étaient élevées avec les deux modes de scan (rg= 0.90 à 0.98). En conclusion, la mesure de la taille des citernes de lait par la méthode de côté est plus recommandée, bien que les mesures avec la méthode du bas montrent des coefficients d’héritabilité légèrement plus élevés.

English

We studied the size of mammary cistern in ewes of 9 genotypes (purebred Improved Valachian (IV), purebred Tsigai (T), purebred Lacaune (LC) and their crosses with genetic proportion of specialized dairy breeds Lacaune and East Friesian (EF) - (25 %, 50 % and 75 %) were evaluated. Data were evaluated using REML methodology and MIXED procedure (SAS/STAT). The effect of genotype showed the highest influence (P<0.001) on the length and area of the left and right udder cisterns measurements. In purebred IV ewes, the average areas of the left and right udder cisterns sizes were obtained by using the side method were (1519.39±77.212 mm 2 ).

B-mode and Doppler sonography of the mammary glands in dairy goats for mastitis diagnosis.

This study aimed to evaluate the sonographic characteristics of the udder and teats and to determine the Doppler indexes of mammary artery in healthy and undergoing subclinical and clinical mastitis goats. Thirty animals among Saanen and Alpine Brown goats were arranged in three groups, healthy goats (HG), goats with subclinical mastitis (SMG) and goats with clinical mastitis (CMG). Using the B-mode, the sonographic characteristics (echotexture and echogenicity) and biometry (diameter and area of the udder cistern, diameter and area of the teat cistern and thickness of the teat wall) were evaluated. Using Doppler ultrasonography, the vascular indexes of the mammary artery were obtained. It was observed hyperechogenicity with solid component in the gland cistern when comparing animals with clinical mastitis and healthy mammary tissue. Regarding the echotexture of the breast tissue, there was heterogeneity in the mammary parenchyma on the three groups, for the milk, it was observed homogeneity for animals on HG and SMG and heterogeneity for animals on CMG. Grey-scale quantitative assessment revealed increase in echogenicity (mean value) for all the structures when comparing the three groups. Biometry did not reveal statistical difference between groups, for none of the evaluated structures. Doppler examination of the mammary artery showed the decrease of end diastolic velocity and raise of pulsatility index between groups. The association of B-mode and Doppler ultrasonography is useful for the evaluation of the udder of dairy goats with mastitis. It is a sensitive and specific method for the study of this disease. Doppler mode was unable to establish reliable criteria for diagnosis of subclinical mastitis. Moreover, the quantification of echogenicity is a useful technique for the evaluation of the milk in animals with mastitis; therefore, it is suggested that it can be used as complementary technique for the diagnosis of mastitis in goats.

Dairy sheep production research at the University of Wisconsin-Madison, USA - a review.

Commercial milking of sheep is a new agricultural industry in the United States starting approximately 30 yr ago. The industry is still small, but it is growing. The majority of the sheep milk is used in the production of specialty cheeses. The United States is the major importer of sheep milk cheeses with 50 to 60% of annual world exports coming to the United States during the past 20 yr. Therefore, there is considerable growth potential for the industry in the United States. The only dairy sheep research flock in North America is located at the Spooner Agricultural Research Station of the University of Wisconsin-Madison. The research program started in 1993 and has been multifaceted; dealing with several areas important to commercial dairy sheep farmers. The East Friesian and Lacaune dairy breeds were compared and introduced to the industry through the research program. Both dairy breeds produced significantly more milk than traditional meat-wool breeds found in the U.S., but the two breeds differed in their production traits. East Friesian-cross ewes produced more lambs and slightly more milk than Lacaune-cross ewes whereas Lacaune-cross ewes produced milk with a higher percentage of fat and protein than East Friesian-cross ewes. Lactation physiology studies have shown that ewes with active corpora lutea have increased milk yields, oxytocin release during milking is required to obtain normal fat percentages in the milk, large udder cisterns of dairy ewes can allow for increased milking intervals, and short daylengths during late pregnancy results in increased milk yield. In the nutrition area, legume-grass pastures and forages with a higher percentage of legume will result in increased milk production. Grazing ewes respond to additional supplementation with increased milk yield, but it is important to match the supplement to the quality of the grazing. Ewes on high quality legume-grass pastures that are high in rumen degradable protein respond with increased milk production to supplements high in energy and/or high in rumen undegraded protein.

Comparison of external udder measurements of the sheep breeds Improved Valachian, Tsigai, Lacaune and their crosses

Morphological udder traits have recently become of greater interest from farmers to researchers. In dairy ewes, the udder is very important due to its physiological and conformational characteristics. External udder traits were measured in ewes ( Ovis aries L.) of nine genotypes (355 ewes) created of the basis of Improved Valachian (IV), Tsigai (T), and Lacaune (LC) breeds (six traits; 1185 data for each trait) during the milking period 2002-2008. Udder measurements were assessed for: udder length (UL), udder width (UW), rear udder depth (RUD), cistern depth (CDE), teat length (TL), and teat angle (TA). Data were processed by restricted maximum likelihood (REML) methodology using a MIXED procedure from the SAS statistical package. All studied parameters were influenced by the genotype (P < 0.001), many of them also by the effect of parity and lactation stage. The exactly detected UL, UW and RUD during the lactation and with the age of ewes expand gradually (P < 0.001). Teat length was greater in older ewes (expanding, with the parity). Indicator TA during lactation worsened. Crosses with 25 to 75% share of genetic dairy breeds (in particular with LC, to a lesser extent ‘East Friesian’ - EF) were in most cases larger than the udder cisterns of purebred ewes T and IV. Purebred LC had the largest udders, with the largest cisterns. In conclusion, crosses with specialized dairy breeds have more suitable udders for machine milking than purebred default breeds (T, IV, LC) and are suitable for machine milking.

Udder Morphological Traits and Milk Yield of Chilota and Suffolk Down Sheep Breeds

Morphological traits of the whole udder (circumference, width, height, and length), teats (angle, length and width), udder cistern (teat opening and cistern height), and milk yield were measured over one lactation in a total of 18 ewes (nine Chilota and nine Suffolk Down sheep) belonging to the same experimental flock (Centro Experimental INIA Butalcura, Chiloe, Chile). Analysis of variance showed significant effects for breed, sheep within breed, and stage of lactation. Chilota ewes evidenced greater udder circumference (433 mm), udder length (86 mm), teat opening (96o), and milk yield (947 mL d -1 ) than Suffolk Down ewes (410 mm, 77 mm, 93o, and 559 mL d -1 , respectively). Udder circumference, udder width, udder length, cistern height and teat size significantly decreased throughout lactation. Repeatabilities of all traits were between 0.17 and 0.60; the highest repeatability was for udder circumference. This trait is easy to measure and had a discriminatory value for breed differentiation. In conclusion, Chilota sheep had a dairy aptitude greater than Suffolk Down sheep and similar to Spanish and Mediterranean dairy sheep breeds at beginning of their breeding programs.

Relationship between mammary morphology traits and milk yield of Sicilo-Sarde dairy sheep in Tunisia

Sicilo-Sarde is a local breed from northern Tunisia resulting from crossing Sarda and Comisana dairy sheep and is traditionally used for cheese production after lamb weaning. A sample of 52 adult Sicilo-Sarde lactating ewes was used for studying their udder morphological traits and milk yield potential during weeks 4–8 (milking–suckling period) and 10 (milking period) of lactation. Daily milk yield was estimated on a daily basis by using the double oxytocin injection method 4 h after machine-milking at d 30 and 45. Udder and teat morphology were also measured at d 45 of lactation. Cisternal area (by ultrasonography) and udder compartments (cisternal and alveolar milk) were evaluated 8 h after milking by using atosiban and oxytocin on d 72 of lactation. Milk yield averaged 0.56 ± 0.10 L/d and ewes had small (volume, 496 ± 28 mL) and healthy udders (CMT, <1), with medium sized teats (length, 18.5 ± 4.9 mm; diameter, 10.0 ± 2.0 mm) attached at 45 ± 10°. A drop in milk production (49%) was found in the transition from suckling (day 30) to milking (week 10). Udder cisterns were multilocular and small sized (half udder area, 11.6 ± 4.5 cm 2), although cisternal milk accounted for 54% of the total milk in the udder. Correlation between cisternal milk and cisternal area was moderate ( R 2 = 0.48; P < 0.05). Lag time and total milking time were 1.9 ± 0.1 and 31 ± 5 s, respectively. In conclusion, the Sicilo-Sarde ewes evaluated showed medium sized cisterns and teats which were morphologically adequate for machine milking, although milk production needs to be improved.

Udder measurements and milk production in two Awassi sheep genotypes and their crosses

To improve the effectiveness of community-based breeding programs for increased milk production, the values of different udder measurements for predicting milk production traits during the milking period were assessed over 3 yr on 273 Awassi ewes. Machine milking of ewes began after weaning, 56 d after parturition, and continued until the milk yield of the ewes was <200 mL/d. Milk yield obtained by hand milking and milk composition were measured weekly, and days in milk, total milk yield, and total yields of protein, fat, and nonfat solids in milk were calculated for each ewe. On d 70 of milking, morphological traits of the whole udder (circumference, width, height, and length), udder cistern (height), and teats (length, width, and position score) were measured. On the same day, the milk yield of ewes was recorded by hand milking. Positive and moderate to strong correlations (r=0.36 to 0.76) between udder circumference and width, teat width, and milk production traits of total milk yield, and total yields of protein, fat, and nonfat solids were found. However, a more accurate predictor of milk production traits was milk yield on d 70, as higher positive correlations between this variable and the milk production traits were found (r=0.63 to 0.89). Nine farmers were invited to independently estimate the hand-milked milk yield performance of a sample of 169 ewes (d 15 to 45 of milking) by visually observing each ewe and making a subjective linear score (1 to 5). Their assessments were significantly correlated with milk yield on the day of the observation (r=0.52), total milk yield (r=0.50), and days in milk (r=0.45). Considering the perception details provided by farmers concerning each of the subjective linear scores, it was found that most predictive linear udder measurements of udder circumference and width and teat width identified in this study were implicit in these scores. The predictive ability of the measurements studied have practical implications for community-based breeding programs involving improvement of milk production—not just in Syria, but in other countries in dry areas as well—because it is possible for experienced farmers to visually assess milk production of dairy ewes or take simple udder measurements with predictive value.

Effects of milking interval and cisternal udder evaluation in Tunisian Maghrebi dairy dromedaries (Camelus dromedarius L.)

Effects of 4 different milking intervals (8, 12, 16, and 24h) on milk yield and milk composition were studied in Tunisian Maghrebi dairy dromedaries (n=6) at late lactation [240±14 days in milk (DIM), 5.84±1.62 L/d]. Camel-cows suckled their calves for 2 mo, were hand milked while suckling until mo 4 of lactation (calf weaning) and machine milked thereafter. Intravenous injection of oxytocin was administered before machine milking at each experimental milking to induce complete milk ejection and to avoid carryover effects of milking intervals. Cisternal and alveolar milk were measured at 380±16 DIM for a 24-h milking interval. Milk accumulated logarithmically (R2=0.95) in the udder from 8- to 24-h milking interval without reaching a plateau. Consequently, milk secretion rate decreased exponentially (R2=0.93) according to milking interval. Compared with 12-h milking interval (6.1 L/d), estimated daily milk yield was 113, 87, and 70% for 8-, 16-, and 24-h intervals, respectively. Total milk solids, milk fat content, and milk pH decreased with increasing milking interval, showing the greatest value at 8-h intervals (14.1±0.4%, 4.6±0.5%, and 6.66±0.05, respectively) and the lowest at 24-h intervals (12.3±0.9%, 2.9±0.6%, and 6.54±0.02, respectively). Milk protein (3.9±0.1%), lactose (4.5±0.2%), ash (0.84±0.01%) and density (1.028±0.01) remained constant for all milking intervals. Milk K, Ca, and Mg contents increased as milking interval increased, but Na content did not change (0.06±0.01%, on average). Milk Na:K ratio tended to decrease from 0.35 (1:2.9) to 0.22 (1:4.5) for the extreme milking intervals. Plasma lactose concentration steadied from 8- to 16-h (67±32 μmol) but increased dramatically at 24-h intervals (338±118 μmol), indicating that mammary tight junctions became permeable after 24h of milk accumulation. Camel udders showed small cisterns (19.3% of total milk in the udder at 24h) when compared with other dairy animals; we recommend the use of prestimulation for machine milking and selection for larger udder cisterns. Alveolar milk contained more fat (5.16 vs. 1.75%; SEM, 0.39%) and protein (3.23 vs. 2.73%; SEM, 0.15%) than cisternal milk. Despite the increase of plasma lactose during tight junction leakiness, the tendency for the Na:K ratio to decrease may be indicative of a camel's specific regulatory mechanism for controlling Na and K concentrations in milk and delaying the inhibitory effect of milk stasis on milk secretion rate. In conclusion, this short-term study proved the low storage capacity of the Tunisian Maghrebi camel udder but also showed their moderate ability to adapt to extended milking intervals at late lactation.

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

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.

Plasma vasopressin and oxytocin concentrations increase simultaneously during suckling in goats

Goats are often kept on small farms where they suckle kids and are hand milked for human consumption. Our first objective was to investigate whether vasopressin secretion increases together with oxytocin during hand milking and suckling in seven goats 6-8 weeks after parturition. Four goats suckled and three were hand milked on the first day and the treatments were reversed on the next day. Blood samples were taken via a semi-permanent catheter. Plasma concentrations of vasopressin and oxytocin increased during suckling, but not during hand milking. Plasma cortisol concentration was elevated for 10 min after both treatments. These results initiated a second series in which the objectives were to measure vasopressin and oxytocin concentrations during hand milking in a larger number of goats and to investigate whether the rise in cortisol concentration was due to the experimental conditions or to milking, by adding a no-milking treatment. Nine goats in lactation weeks 4-10 were studied. Heart rate and arterial blood pressure were registered in eight of the goats. Oxytocin concentration did not change during hand milking and the vasopressin concentration was below the detection limit. Heart rate and blood pressure were elevated during milking and for about 10 min thereafter. Cortisol concentration increased after milking, as above. None of the variables changed in the no-milking treatment. This suggests that the rise in cortisol concentration was due to milk excretion and was not a stress reaction. In conclusion, suckling increased plasma concentrations of vasopressin and oxytocin, but hand milking did not. In a mixed system, presence of the kids may be necessary to stimulate release of the peptides and thereby contraction of the myoepithelial cells. However, milk stored in the udder cisterns can be obtained by hand milking without presence of oxytocin or vasopressin.