Udder Morphology Traits Research Articles

Relationship between udder morphology traits, alveolar and cisternal milk compartments and machine milking performances of dairy camels (Camelus dromedarius)

A total of 22 dairy dromedary camels under intensive conditions in late lactation (275±24 days) were used to study the relationship between external and internal udder morphology and machine milking performances. Measurements of udder and teat morphology were obtained immediately before milking and in duplicate. Individual milk yield, lag time and total milking time were recorded during milking, and milk samples were collected and analyzed for milk composition thereafter. Cisternal and alveolar milk volumes and composition were evaluated at 9 h milking interval. Results revealed that dairy camels had well developed udders and milk veins, with medium sized teats. On average, milk yield as well as milk fat and protein contents were 4.80±0.50 L d-1, 2.61±0.16% and 3.08±0.05%, respectively. The low fat values observed indicated incomplete milk letdown during machine milking. Lag time, and total milking time were 3.0±0.3, and 120.0±8.9s, on average, respectively. Positive correlations (p<0.05) were observed between milk yield and udder depth (r=0.37), distance between teats (r=0.57) and milk vein diameter (r=0.28), while a negative correlation was found with udder height (r=-0.25, p<0.05). Cisternal milk accounted for 11% of the total udder milk. Positive correlations were observed between total milk yield and volume of alveolar milk (r=0.98; p<0.001) as well as with volume of cisternal milk (r=0.63, p<0.05). Despite the low udder milk storage capacity observed in dairy camels, our study concluded that the evaluated dromedary sample had adequate udder morphology for machine milking. Finally, positive relationships were detected between milk yield and udder morphology traits of dairy camels.

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.

Phenotypic and genetic relationships between udder morphology and udder health in dairy ewes

The aim of this paper was studying the phenotypic and genetic relationships between udder morphology traits and udder health in dairy sheep. From 2000 to 2008 udder traits, somatic cell count (SCC) and clinical mastitis cases were recorded in an experimental flock consisting each year of around 900 ewes. A logistic regression was performed to evaluate the risk for a ewe of showing either a mastitis or at least 2 daily SCC records greater than 1 × 10 6 cells/ml in one of its lactations as function of udder traits scored in 1st lactation. 1587 individual udder scores and 39,950 SCC daily records were used for the analysis. Secondly, genetic correlation between lactation mean of somatic cell score and udder traits were estimated by a REML method applied to four bi-trait animal models, using data from 2251 primiparous ewes. Logistic regression results indicated that the risk of mastitis or high SCC values during the productive life increased as the cistern height increased and the degree of udder suspension and udder depth decreased. This suggests that the appraisal of the udder is a useful tool for culling decision aimed at increasing the sanitary status of the flock. The genetic correlation between lactation SCS and udder traits were favourable for udder depth (−0.50 ± 0.12), teat placement (0.39 ± 0.011) and degree of udder suspension (−0.42 ± 0.011) and closed to zero for the degree of separation of the two halves. Thus selection for udder morphology, already implemented in some dairy sheep breeds with the aim of improving machine milkability, will lead to a favourable correlated genetic response on SCC.

Relationships among udder characteristics, milk yield and, non-yield traits in Frizarta dairy sheep

In the present study the relationships between five body structural and nine udder morphological traits with milk yield and non-yield traits, i.e. milk contents, somatic cell count and body weight in n = 171 Frizarta ewes were investigated. Positive correlations of moderate to high magnitude were observed among body measurements ranging from 0.25 (body length-chest width) to 0.61 (chest width-chest girth). High correlations were observed between udder width and udder circumference ( r = 0.69) as well as between udder circumference at base and middle ( r = 0.62). Udder height was found to be positively correlated with cistern depth ( r = 0.32), udder width ( r = 0.40) and udder circumference ( r = 0.42) as well as with teat measurements (0.19 and 0.25 with teat length and teat circumference, respectively). Cistern depth was positively and highly correlated with teat angle ( r = 0.64). The correlation between teat length and circumference was also high ( r = 0.57). Teat angle was found to be negatively correlated with teat measurements ( r = −0.39 and −0.23 for teat length and teat circumference, respectively). Principal components analysis revealed four components that jointly explained 67% of the variance of all the body and the udder morphological traits. The first principal component interpreted as the body dimensions was found to be associated with body weight of ewes. The second component interpreted as global and rear measurements of the udder was significant for milk yield traits. The third and fourth principal components were interpreted as the udder type and teat dimensions, respectively. Ewes’ body weight could be adequately predicted by chest girth, body length, chest width and withers height. Test day milk yields were found to be associated with udder circumference and udder width as well as with udder height and teat length. None of the udder measurements and/or teat characteristics was found to be correlated with milk content(s) and/or somatic cell count. New statistical techniques can be successfully implemented in investigation of relationships between various traits in dairy sheep.

Relationship between udder and milking traits during lactation in Istrian dairy crossbreed ewes

The aim of this study was to determine the udder morphology and milking characteristics changes throughout lactation during machine milking of the sheep. Additionally, udder morphology was analyzed by using slide ruler and digital picture. Milking characteristics were influenced by milking interval and day of lactation. Udder morphology traits did not change throughout lactation, except for udder width. The repeatability between slide ruler and digital picture measurements was high (r=0.53 to 0.68). Milkability in Istrian dairy crossbreed ewes could be improved if udder traits are incorporated in selection scheme. Digital picture analysis for faster recording of udder morphology measurements in sheep can be used.

Relationship Between Udder Measurements and The Linear Scores for Udder Morphology Traits in Kıvırcık, Tahirova and Karacabey Merino Ewes

Relationship Between Udder Measurements and The Linear Scores for Udder Morphology Traits in Kıvırcık, Tahirova and Karacabey Merino Ewes

The first observation of milkability of the sheep breeds Tsigai, Improved Valachian and their crosses with Lacaune

The aim of this study was to evaluate the milkability of two purebred breeds Tsigai (TS, &lt;i&gt;n&lt;/i&gt; = 14) and Improved Valachian (IV, &lt;i&gt;n&lt;/i&gt; = 15), their crosses with Lacaune 50% TS × 50% LC (&lt;i&gt;n&lt;/i&gt; = 13), 50% IV × 50% LC (&lt;i&gt;n&lt;/i&gt; = 9) and purebred Lacaune (LC, &lt;i&gt;n&lt;/i&gt; = 19). The measurements of the milk flow were performed on day 90 ± 10 of lactation during evening machine milking. The recording of milk flow was carried out by the equipment for graduated electronic recording of milk level in a jar in one-second intervals. The milk flow curves were classified into four types: 1 peak (1P), 2 peaks (2P), plateau I (maximal milk flow over 0.4 l/min (PLI)), plateau II (maximal milk flow less than 0.4 l/min (PLII)). The last two types refer to ewes with steady milk flow during milking. Udder morphology traits were measured (cisternal depth, teat angle) and subjectively assessed by the use of linear scores (cistern depth, teat position). The average total milk yield was 0.335 ± 0.043, 0.392 ± 0.042, 0.407 ± 0.042 l in purebred TS, IV, LC resp. and 0.397 ± 0.046, 0.434 ± 0.056 l in crosses TS × LC and IV × LC, resp. The frequency of occurrence of different types of milk flow /1P:2P:PLI:PLII/ was 27, 47, 22, 4%, resp. The highest milk yield was observed in ewes with PLI (0.481 ± 0.045 l), followed by 2P (0.401 ± 0.029 l) and 1P (0.293 ± 0.036 l) type of milk flow curve (&lt;i&gt;P&lt;/i&gt; = 0.0112). An opposite effect was observed in the percentage of machine stripping yield where 1P had 41.94 ± 3.83%, 2P 21.29 ± 3.04% and PLI 15.90 ± 4.70% (&lt;i&gt;P&lt;/i&gt; &lt; 0.0001). LC and TS × LC, IV × LC had the more horizontal teat position than TS and IV. It can be supposed that at least during around 69% milkings the sheep released oxytocin in response to machine milking and that TS, IV and their crosses with LC also have a suitable potential for machine milking.

Quantitative Trait Loci Underlying Udder Morphology Traits in Dairy Sheep

A genome scan was conducted on the basis of the daughter design to detect quantitative trait loci (QTL) influencing udder morphology traits in Spanish Churra dairy sheep. A total of 739 ewes belonging to 11 half-sib families were genotyped for 182 microsatellite markers covering 3,248.2 cM (Kosambi) of the ovine autosomal genome. Phenotypic traits included scores for 5 linear udder traits: udder depth, udder attachment, teat placement, teat size, and udder shape. Quantitative measurements for the QTL analysis were calculated for each trait from evaluation scores using within-family yield deviations corrected for fixed environmental effects. Joint analysis of all families using Haley-Knott regression identified 5 regions that exceeded the 5% chromosome-wise significance threshold on chromosomes 7, 14, 15, 20, and 26. Based on the across-family results, a within-family analysis was carried out to identify families segregated according to the QTL and to estimate the QTL effect. The allelic substitution effect for individual families ranged from 0.47 to 1.7 phenotypic standard deviation units for udder shape on chromosome 15 and udder depth on chromosome 14, respectively. These QTL regions provide a starting point for further research aimed at the characterization of genetic variability involved in udder traits in Churra sheep. This paper presents the first report of a sheep genome scan for udder-related traits in a dairy sheep outbred population.

Investigating the relationship between the prion protein locus and udder morphology traits and milk yield in Sardinian sheep1,2

Different approaches were applied to investigate prion protein (PrP)-encoding gene effects on udder morphology and milk yield in Sardinian sheep. The PrP genotype of 23,077 animals (10,029 males) was determined. The direct effect of the PrP or a closely linked gene was analyzed at the population-wide level using 2 animal models, based on records from genotyped animals, including only the PrP genotype as a fixed effect. In the female model, the dependent variable was animal performance deviation, calculated as the sum of the individual random effects. The male model was based on daughter yield deviations. Both dependent variables were obtained from the national genetic evaluations of 2005. The significance of pairwise comparisons between genotypes was assessed by using the Tukey-Kramer multiple-comparison procedure. Within-family analyses were performed on sires heterozygous for the PrP gene to detect those genes that affect the traits of interest and are not in linkage disequilibrium with the PrP locus at the population-wide level. The overall results led us to exclude either a direct or a linkage gene effect of the PrP locus on udder morphology or milk yield in Sardinian sheep. A further analysis of males that neglected the relationship matrix was carried out to evaluate the effect on the loss of genetic gain of the different selection pressures applied on resistant and susceptible genotype classes. Significant differences between genotypes were detected for milk yield. These were due to the different selection pressures applied to the PrP genotype classes. Finally, no negative correlated genetic response on the selection traits is expected from the selection for scrapie resistance in the Sardinian breed. However, a loss of genetic gain for milk yield is likely to occur in the future due to the different selection pressures on resistant and susceptible males.

Relationships between external and internal udder measurements and the linear scores for udder morphology traits in dairy sheep

Udder morphology traits were measured and subjectively assessed by the use of linear scores in 266 ewes of Tsigai (T), Improved Walachian (IW) and Lacaune (LC) dairy breeds. Animals were recorded repeatedly within and between lactations, therefore 772 sets of measurements and linear scores were collected in total. Udder measurements included: udder length, udder width, rear udder depth, cistern depth, teat length, teat angle, sum of cistern cross-section areas scanned by the ultrasound technique from the side and from the bottom in a water bath. Linear scores were assessed for: udder depth, cistern depth, teat placement, teat length, udder attachment, udder cleft, and udder shape from the aspect of machine milking. Analysis of variance was conducted by the mixed procedure of SAS statistical package. The model included effects of experimental day, parity, days in milk, random effect of animal and residual error. Subsequently, correlations between random animal effects for udder measurements and linear scores were computed for individual examined breeds separately. Subjectively assessed linear scores for udder depth, cistern depth, teat position and teat size showed high correlations with actual measurements of the respective traits on udder in all examined breeds (r&lt;sub&gt;p&lt;/sub&gt; = 0.65&amp;ndash;0.80). Linear scores for cistern depth and teat position were highly correlated (r&lt;sub&gt;p&lt;/sub&gt; = 0.84; 0.77 and 0.90 for T; IW and LC ewes), suggesting that they are nearly identical traits. Linear score for udder shape was significantly correlated with the linear score for udder attachment in all examined breeds (r&lt;sub&gt;p&lt;/sub&gt; = 0.79; 0.80 and 0.78 for T; IW and LC). In T and IW assessments of the udder shape were also highly correlated with linear score for udder height (r&lt;sub&gt;p&lt;/sub&gt; = 0.84 resp. r&lt;sub&gt;p&lt;/sub&gt; = 0.79) while in LC this correlation was close to zero. In LC assessment of the udder shape was more dependent on teat position (r&lt;sub&gt;p&lt;/sub&gt; = &amp;ndash;0.37) and cistern depth (r&lt;sub&gt;p&lt;/sub&gt; = &amp;ndash;0.30). &amp;nbsp;