Teat-end Shape Research Articles

Phenotypic relationships between udder and milking characteristics, milk production and California mastitis test in goats

Data of crossbreed goats (28 Alpine × criolla; 6 Granadina × criolla; 13 Nubian × criolla) kept on natural pasture at Irapuato, México, and hand-milked once a day, were studied for daily milk production (MP), milking time (MT), California mastitis test score (CMT), udder perimeter (UP), teat perimeter (TP), teat length (TL), udder cleft (UC), udder shape (US), teat shape (TS) and teat end shape (TE). UP, TP, TL and UC were measured before milking. Kids were separated from their mothers for a 24-h period prior to milking. Milking rate (MR) was MP/MT. MP ( r=−0.32) and UP ( r=−0.33) were correlated with CMT ( P<0.05). UP had r=0.81 ( P<0.01), and TP had r=0.45 ( P<0.05) with MP. Goats with globular udders had significantly lower values ( P<0.05) for CMT, and higher ( P<0.05) for MR and MP than goats with non-globular udders. Goats with non-balloon teat shape had significantly lower ( P<0.05) CMT values than those with balloon-shaped teats. Results suggest that goats with globular udders and non-balloon-shaped teats have greater resistance to mastitis. UP and TP had greater correlations with MP than other morphological variables.

Relationships Among Udder and Teat Morphology and Milking Characteristics

Teat cup liner slips, manual milking machine adjustments, milk yields, and milking times were recorded during both morning and evening milkings for 8 d on 97 Holstein cows in The Pennsylvania State University dairy herd. Fore and rear udder heights (distance from floor to udder), udder levelness, distances between teats (before and after milking), teat lengths, teat diameters, and teat end shapes were measured on the same cows. Product-moment correlations among the morphological characteristics, liner slips, manual adjustments, milk yields, and milking times were determined. Residual correlations from a model including lactation number and DIM (linear and quadratic) were also calculated. The variation among cows in machine liner slips and manual adjustments within and across lactation number and DIM can be partially explained by udder and teat morphology. Wider teats were associated with increased liner slips and increased manual adjustments. More tilted udders (rear quarters lower than front quarters) were associated with increased liner slips and tended to be associated with increased manual adjustments. In addition, larger teat diameters and longer teats tended to be associated with increased liner slips.

Impact of milking characteristics and teat morphology on somatic cell counts in first-lactation Norwegian cattle

Data from the Norwegian progeny-testing program were used to examine the impact of milking characteristics and teat morphology on log e somatic cell counts (SCC) in first-lactation Norwegian Cattle. Three primary independent study variables (2-min milk, milk leakage and teat-end-to-floor distance) were evaluated in addition to six other study variables and six potential confounding variables. Seven different regression models were evaluated. Sire and herd were identified as confounding variables. The chosen model was based on 4090 cows in 1993 herds, sired by 119 bulls, and had a coefficient of variation of 0.59. Increased 2-min milk, decreased teat-end-to-floor distance and inverted or pointed teat-end shapes were significantly ( P ≤ 0.01) associated with a higher log e SCC. Effect of herd was absorbed in the model and explained ∼ 50% of the total variability in log e SCC, whereas sire and the total effect the study variables explained < 5% each. Among-herd variability is discussed in relation to the study design.

Heritabilities of Teat Traits and their Relationships with Milk Yield, Somatic Cell Count, and Percent Two-Minute Milk

Two teats on one side of the udder of 898 Holstein cows were scored on a continuous scale for shape, orientation, and pigmentation. Corresponding teat ends were scored for shape, lesions, pigmentation, and orifice location. Teat lengths and diameters, udder height, and distances between teats were measured on the same day. Cows were from six herds owned by the North Carolina Department of Agriculture and two North Carolina State University research herds. Repeatabilities from 98 cows rescored 6 mo after initial scoring were: .54, teat shape; .76,teat-end shape;.98, teat pigmentation; .98, orifice pigmentation, and .32, lesion score. Heritabilities based on 72 paternal half-sister groups were: .38, teat shape; . 5 5, teat-end shape;, 55, teat pigmentation; .40, orifice pigmentation; .24,lesion score; .19, orifice location. Those for four traits of teat orientation averaged .18. Corresponding heritabilities from 200 cow-dam pairs were .37, .67, .55, .30, .22, and .48.Teat-end shape was related to somatic cell count and percent 2-min milk. Somatic cell counts were influenced by udder height, teat-end shape, percent 2-min milk, lesion score, and teat diameter. Teat shape, length, diameter, pigmentation, and orientation did not have large effects on economically important traits.

Heritability of Teat Shape and Teat End Shape in Cattle

Lojda L., M. Stavikova, J. Polai!ek.: Heritability of Teat Shape and Teat End Shape in Cattle. Acta vet. Bmo, 51, 1982: 59-67. Heritability of teat shape and teat end shape was studied in Bohemian Pied cows. Teat shape was evaluated by visual inspection and on the basis of indices 11 and II pro­ posed in this study. The coefficients of heritability of the two indices computed from the regression of daughter on dam in 185 dam-daughter pairs were 0.380 ± 0.08 and 0.354 ± 0.08, respectively. The coefficient of heritability of teat end shape com­ puted from the dam-daughter regression was 0.414 ± 0.17, but the coefficient of her i­ tability of this characteristic computed by means of the intraclass correlation coefficient in groups of paternal half sisters sired by 30 bulls was only 0.085. Fourteen pairs. of dizygotic twins were included in the study to investigate their concordance with regard to teat shape and teat end shape. Half of the pairs of twins both had all 4 teats of equal shape; 3, 2 and 1 equally shaped teats were found in 3, 1 and 1 pairs, res­ pectively, and two pairs were completely discordant. The concordance of twins with regard to teat end shape was also considerable: 78.5 per cent of the pairs both had 4, 3 or at least 2 teats with equally shaped ends and only 2 pairs were completely discor­ dant. Where the dams of the twins were available for comparison, their teat and teat end shapes agreed with those of one of their daughters at least. Cattle, heritability, teat shape, teat end shape, mastitis.

Subjective Evaluation of Teat Canal Anatomy

Since radiographic techniques have shown that streak canals with larger diameters tend to milk-out faster and are more susceptible to new intramammary infections, a practical visual test was sought to provide easier determination of cows with either extremely narrow (slow milking) or extra wide (susceptible to new infections) streak canals.A subjective teat classification scheme was developed to describe five different teat-end shapes in 159 Holstein and Brown Swiss cows in the University of Nebraska dairy herd. Approximately one-fourth of the cattle had pointed or round teat ends, one-half had flat or near flat, and one-fourth were either disk or cone-shaped at the distal end.The correlation coefficient of repeated observations varied between .67 and .84, generally increasing as the time span between observations shortened. About 40% of variation in future classification scores is unaccounted for by past classification scores and may be the result of human error. I conclude, however, that this teat classification scheme has sufficient repeatability as an aid to selection, especially in springer heifers close to freshening.