Rear Udder Width Research Articles

Factor analysis for udder and teat type traits in Sahiwal and Karan Fries cows

Selecting female cows for productivity based on udder and teat traits is essential in field due to lack of available records. The objective of the present study was to reduce the dimensionality of the 17 udder and teat traits and to analyse their impact on milk productivity. The data on 256 cattle comprising 133 Sahiwal and 123 Karan Fries cows were used in this study over the years 2017-2019 from Livestock Research Centre (LRC) of ICAR-National Dairy Research Institute, Karnal. The 17 udder and teat traits were fore udder attachment (FUA), rear udder width (RUW), rear udder height (RUH), udder balance (UB), udder depth (UD), udder length (UL), udder width (UW), udder circumference (UC), central ligament/udder cleft (CL), teat circumference (TC), fore teat length (FTL), rear teat length (RTL), distance between fore and rear teat (DFR), distance between left and right teat (DLR), shortest distance from floor to fore teat (SDFT), shortest distance from floor to rear teat (SDRT) and teat diameter (TD). In the factor analysis, first five latent factors accounted for 62.22% of total variance in udder and teat measurements for Sahiwal cows and 65.67% in Karan Fries (KF) cows, respectively. In Sahiwal cows F1 represented better udder support and wideness (wide udders, udders were supported by strong suspensory ligament), whereas in KF cows, first factor reflected better udder dimension and distance between teats (longer length, width of udder and well placed teats). Factor analysis could reduce the multicollinearity of the data. It can be concluded that inclusion of udder and teat measurements in selection index can be a reliable criteria for selecting cows for higher milk yield.

Type Traits of Holstein-Friesian and Red-Holstein Cows Raised Together in a Private Farm in Aydın Province

This study was aimed at comparing the conformation traits of two different cattle breeds such as Holstein-Friesian (HF) and Red-Holstein (RH) cows raised together in a farm in Aydın, Türkiye. In this study, 102 HF and 19 RH cows in different lactations numbers (LN) forming a total of 121 cows were used. The type traits were determined using Linear Type Traits (LTT) based on 9 points scoring system and non-linear 100 points method. The LTT were composed of body traits such as Stature (St), Chest Width (CW), Body Depth (BD), Rump Angle (RA), Rump Width (RW) and Body Condition Score (BCS); foot and legs traits: Rear Legs Set Angle (RLA), Rear Legs Rear View (RLV), Real Legs Knee Structure (RLS) and Foot Angle (FA); udder traits: Fore Udder Attachment (FUA), Rear Udder Height (RUH), Rear Udder Width (RUW), Central Ligament (CL), Udder Depth (UD), Rear Teat Placement (RTP), Fore Teat Length (FTL) and Mammary Acuity (MA); and according to the non-linear 100 points method: Dairy Strength (DS, 15%), Frame (20%), Foot and Legs (FL, 25%) and Udder (40%). The results of variance analysis showed that no differences between breeds and LN were found in body composite traits while, for Foot and Legs traits, only the RLA was found significant (P

Analysis of the influence of the Norwegian Red bull-sires with different breeding value on milk productivity, health, exterior and reproductive traits of daughters

An analysis of the influence of breeding bulls of the Norwegian Red (NR) breeds with different breeding values (BV) on the milk productivity of daughters, their health, reproductive characteristics, udder characteristics, exterior, and indices of productive use. The study material was the data from the electronic catalog of breeding bulls of the NR breed as of April 4, 2023. The sample was formed from the data of only those breeders recommended for reproduction in 2023 by Geno SA. The animals were grouped according to the Total Merit Index (TMI). Breeding bulls with the highest TMI – 53-35 (n = 24) were assigned to the I group, to the II group – with an average TMI – 34-25 (n = 25), and to the III group – bulls with the lowest TMI – 24-10 (n = 22). As a result of the research, it was established that the most significant influence on the indices of productive use of daughters was observed in breeding bulls of the NR breed of the I group (High production index (HPI) – 118.13 % (Р < 0.001), Grazing index (GI) – 110.88 % (Р < 0.05)). According to the TMI index, bulls of the I and II groups prevailed over the sires of the III group, according to their improving effect, on such signs of milk productivity of daughters as milk yield (Р < 0.01), amount of milk fat (Р < 0.05; Р < 0.01) and protein (Р < 0.01; Р < 0.001) and milk productivity index (Р < 0.001 and Р < 0.01) in daughter cows. The greatest improving effect on the udder health of the daughter cows was observed in breeding bulls of the NR breed with TMI 53-35. Bull-sires of groups I and II reduced the number of somatic cells count in the milk of daughter cows by 15.58 and 9.16 %, and bulls of III – only by 3.82 %. Breeder bulls of groups I and III increased milking speed in daughter cows by 4.25 and 1.68 %, and breeders of group II decreased it by 1.96 %. However, the difference was significant only between groups I and II (P < 0.05). Studied breeding sires increased daughters' stature (height) in all groups. Group I sires had the most significant influence on daughters' stature – 114.88, and III group sires had the most minor influence – 102.00. However, the difference was significant between the I and II and I and III groups (Р < 0.05; Р < 0.001). Bull-sires of the I group of the NR breed increased the feet and legs index in daughter cows, as well as the foot angle by 7.58 and 7.38 %, II breeders by 3.48 and 2.48 %, and bulls III reduced these traits in daughters by 0.41 and 0.14 %. The difference between the I and III groups was significant (P < 0.05). Breeder bulls of the NR breed with TMI 53–35 were leaders in improving the udder index of daughters, as well as in reducing its udder depth, strengthening the fore udder attachment, increasing the rear udder width and rear udder height. Therefore, the most significant impact on most of the studied traits was observed in breeding bulls of the NR breed with the highest BV – TMI 53-35. The influence of sires with TMI 53-35 and 34-25 on daughters' milk production was almost the same and improving. However, in terms of the effect on the reproductive characteristics of daughter cows, no significant difference was found between all experimental groups of breeding bulls.

Assessment of body conformation traits and their relationship with production performance of Sahiwal cows

Linear type scoring is key component in decision making process in the herd, as it focusses on the selection of animals with higher productive potential based on their body conformation/linear traits. The present study was carried out on 150 lactating Sahiwal cattle of first to fifth parity. Measurements on linear type traits were recorded 1 h before the evening milking at three different stages of lactation. The average score point of objective linear type traits was stature 5.77±0.08, chest width 4.59±0.10, body depth 5.24±0.10, rump width 5.56±0.09, rump angle 4.48±0.08, rear legs sets 4.81±0.12, foot angle 4.84±0.10, fore udder attachment 4.85±0.11, rear udder height 5.52±0.10, udder depth 5.31±0.08, rear udder width 4.27±0.09, central ligament 4.01±0.09, fore teat length 3.49±0.10, rear teat length 3.94±0.09, teat circumference 4.20±0.11, teat diameter 4.16±0.10 and udder balance 5.25±0.11. On the other hand, average score point of subjective linear type traits (1-9 scale) was angularity 4.69±0.09, rear leg rear view 5.05±0.06, body condition score 6.53±0.08, locomotion 4.88±0.06, fore teat placement 4.41±0.07 and rear teat placement 6.28±0.08. Most of the body conformation traits in Sahiwal cattle were falling under intermediate category and of desirable type. However, some traits like stature, chest width, body depth, rump width, angularity, central ligament, rear udder height, rear udder width and fore udder attachment expressed scope for further improvement.

Genome-Wide Association Study for Body Conformation Traits and Fitness in Czech Holsteins.

The aim of this study was a genome-wide association study (GWAS) on conformation traits using 25,486 genotyped Czech Holsteins, with 35,227 common SNPs for each genotype. Linear trait records were collected between 1995 and 2020. The Interbull information from Multiple Across Country Evaluation (MACE) was included for bulls that mostly had daughter records in a foreign country. When using the Bonferroni correction, the number of SNPs that were either significant or approached the significance threshold was low-dairy capacity composite on BTA4, feet and legs composite BTA21, total score BTA10, stature BTA24, body depth BTA6, angularity BTA20, fore udder attachment BTA10. Without the Bonferroni correction, the total number of significant or near of significance SNPs was 32. The SNPs were localized on BTA1,2,4,5,6,7,8,18,22,25,26,28 for dairy capacity composite, BTA15,21 for feet and legs composite, BTA10 for total score, BTA24 stature, BTA6,23 body depth, BTA20 angularity, BTA2 rump angle, BTA9,10 rear legs rear view, BTA2,19 rear legs side view, BTA10 fore udder attachment, BTA2 udder depth, BTA10 rear udder height, BTA12 central alignment, BTA24 rear teat placement, BTA8,29 rear udder width. The results provide biological information for the improvement of body conformation and fitness in the Holstein population.

Genome wide association study of udder type traits and milk production traits in Gir cattle

This study investigated the association of genome wide association study of udder type traits and milk production traits in Gir cattle. Data for the current study were collected from 635 Gir cows reared by farmers in small-holder conditions, and blood samples were collected for the Genomic study. The data for the phenotypic correlation study on 305 day milk yield and udder type traits were analysed using the statistical software R (v3.4.0), and the genome wide association study was carried out using the PLINK (v1.90b4.4) software. The phenotypic correlation between udder type traits, such as central ligament, rear udder height, rear udder width, teat length, and teat thickness, and 305 day milk yield was low to moderate, but significant (p 0.05) and positive. Some traits, however, were negatively correlated, including fore udder attachment, fore teat placement, rear teat placement, and udder depth. A genome-wide association study using a customised SNP chip (INDUSCHIP1) with 45,024 SNPs distributed on 29 autosomes discovered 838 SNPs that were significantly related to nine udder type traits and 305 day milk yield. The majority of SNPs were under MAF class of 0.3-0.5 from 45,024 SNPs spread over 29 Bos Indicus autosomes. Thus, present study on udder type traits and 305 day milk yield and their GWAS in Gir cattle using INDUSCHIP1 a customised SNP chip has provided the base line data for incorporation of udder type traits in Genomic selection for overall genetic improvement of Gir cattle.

Cows enrolled in a pilot randomized clinical trial evaluating pegbovigrastim administered to dairy cows at dry-off had reduced incidence of intramammary infection.

The objective of this pilot study was to determine if an alternative dosing schedule of pegbovigrastim (PEG; Imrestor; Elanco Animal Health) affects mammary gland health, rear udder width, or milk production of healthy dairy cows. 20 pregnant late-lactation Holstein cows in November 2019 through April 2020. Cows were randomly assigned to receive subcutaneous injections with either 15 mg of PEG (PEG group; n = 10) or a sham injection with saline (0.9% NaCl) solution (control group; 10) administered 7 days before dry-off and at dry-off. Quarter milk samples were collected for bacterial culture and somatic cells before and after dry-off and after calving. Mammary gland width was assessed before and after dry-off. Daily milk yields were evaluated after calving. The incidence of intramammary infection was 5 times greater for quarters of cows in the control group than for quarters of cows that received PEG. The effect of treatment on somatic cell count was not significant, but the effects of period and a treatment-by-period interaction were identified. Treatment did not significantly affect milk production in the subsequent lactation, but the effects of period and an interaction of treatment by period were identified. Rear udder width after dry-off was not significantly affected by treatment, but an effect of period was identified. In this pilot study, cows treated with PEG using an alternative dosing schedule had reduced incidence of intramammary infection and an interaction of treatment by sampling period was observed for milk yield. These results suggest that further studies with larger numbers of cows are warranted.

Non genetic factors affecting udder type traits in Sahiwal cattle

The present study was planned to find out the magnitude of environmental factors affecting udder type traits in Sahiwal cattle. Fourteen type of udder traits were measured for each of randomly selected 100 lactating cattle maintained at Livestock Research farm, NDRI, Karnal, India. The data were analysed by least squares methods using the general linear model procedures including parity, stage of lactation and season of calving at classification as fixed effects. Traits viz. Udder balance, Rear Udder Height, Teat Diameter, Teat Length, Central Ligament, Udder Circumference, Udder Width and Teat Circumference were significantly (p<0.05) affected by parity. Stage of lactation was significant (P<0.05) source of variation for Shortest distance from teat ends to floor, Rear Udder Height, Central ligament and Udder Circumference while season of calving significantly (p<0.05) affected Rear Udder Height, Teat Length and Rear Udder Width. It is, therefore, suggested that in breeding value estimation for udder conformation, these environmental factors should be considered which would justify focusing genetic improvement in Sahiwal cattle.

Influence of WDR41 and ANKRD31 gene polymorphism on udder and teat type traits and mastitis in Karan Fries cows

In the present study, the effect of genetic polymorphism of WD-repeat containing protein 41 (WDR41) and Ankyrin repeat domain containing protein 31 (ANKRD31) gene on 17 traits related to udder and teat type and mastitis in 123 Karan Fries cows was studied. Restriction Fragment Length Polymorphism (RFLP) was used to identify the SNP (410 bp and 475 bp) in PCR amplified product of intron 4 and exon 10 in WDR41 gene. Both of them were polymorphic with Guanine to Adenine transition, and three genotypes namely AA, AG and GG were observed. In ANKRD31 gene, RFLP was used to identify the SNP in 513 bp PCR amplified product of intron 24 and two SNPs were found. We report for the first time that intron 4 and exon 10 of WDR41 gene is significantly associated with udder depth (UD), udder balance (UB), central ligament (CL), teat circumference (TC), SFF and tear diameter (TD), rear udder width (RUW), and mastitis. SNP rs110012582 in intron 24 of ANKRD31 gene is associated significantly with UD, distance between left and right teat (DLR), SFF, and SNP rs473512406 with udder length (UL), udder width (UW), udder circumference (UC), fore teat length (FTL), rear teat length (RTL), distance between fore and rear teat (DFR), DLR and mastitis. This information can augment future studies to determine the role of WDR41 and ANKRD31 genes as a candidate gene marker with desired udder and teat conformation and mastitis. Thus, it is essential to work for better udder health and prevent the incidence of mastitis in the herd.

An algorithm-based approach for identification of most relevant linear traits for selecting high producing Murrah buffaloes

Selection of high producing dairy animals is important for dairy profitability and future breeding stock. Thefarmers have relied on physical characters for identification of milk producing ability in animals. In the presentstudy feature selection algorithm were implemented to identify most relevant traits for prediction of peak milk yieldin buffaloes. Based on data recorded from 259 lactating Murrah buffaloes, 14 different body and udder conformation traits, viz. Body Length (BL), Height at Wither (HW), Heart Girth (HG), Body Depth (BD), Paunch Girth (PG), Naval-Udder Distance (NUD), Udder Depth (UD), Rear Udder Height (RUH), Fore Teat Distance (FTD), RearTeat Distance (RTD), Fore Rear Teat Distance (FRTD), Teat Length (TL), Rump Width (RW) and Rear UdderWidth (RUW) were selected. Descriptive statistical analysis revealed that the correlation with peak yield is highestfor RUH, followed RUW, lactation number (LN), NUD, FRTD, HG, RW, RTD, UD, TL, PG, BL, BD, HW andFTD. Correlation-based feature selection in ‘WEKA’ software platform suggested that nine parameters have highcorrelation with peak yield – UD, NUD, RTD, FRTD, TL, RW, RUW, RUH and TL. The Multiple linear regression(MLR) was implemented using the linear regression function available under function classifier in WEKA. TwoRegression models (Model 1 and Model 2) were developed using all fifteen input parameters and with subset of 9input parameters suggested in ‘feature selection’. All models were trained and validated with 10-fold cross validation method. The performance of models developed for prediction peak milk yield was evaluated using the metrics correlation coefficient and root mean squared error (RMSE). Comparison of the performance evaluation matrices revealed that the Model 2 requiring lesser number of inputs is good enough in predicting peak yield with 0.8429 correlation coefficient and 2.16 root mean squared error.

Udder and teat morphometry in relation to clinical mastitis in dairy cows.

The present study was undertaken to explore the association of occurrence of clinical mastitis with udder and teat morphometry in cattle. The relationship of nine udder and eight teat morphometric traits with the occurrence of clinical mastitis was analysed using a binomial logistic regression model. A significant association of the udder and teat morphometric traits with the occurrence of mastitis was observed both in Karan Fries and Sahiwal cattle. The rear udder height, rear udder width, udder width and fore udder attachment were found to be the important udder morphometric traits associated with the occurrence of mastitis. In both groups, mastitic animals had broader rear udder width, lower rear udder height and loose fore udder attachment with lengthy and thicker teats. The inclusion of udder and teat morphometric traits in the selection and breeding program of Karan Fries and Sahiwal cattle may help in selection of animals for mastitis resistance.

Genetic Profiling of PHKA2 Gene and its Association with Udder Type Traits in Indian Dairy Cattle

Background: The experiment aimed to investigate polymorphisms in exon 2 of the PHKA2 gene and investigate the relationship between identified single nucleotide polymorphism and udder type traits in Sahiwal cows. Udder morphometry is being used as a forecaster of production performance in cows since older times. Finding the variants associated with these traits in largely variable region of PHKA2 gene can prove to be highly beneficial. Methods: DNA isolated from Sahiwal cows was analysed by DNA sequencing. Nine udder type and five teat types were measured for each animal according to procedure followed by International committee of animal recording (2012). Result: Three SNPs g.124497381C greater than T, X:124497248 G greater than A and X:124497189 C greater than T were identified. Recessive homozygotes were negligible as mutant allele exhibited very low ranging frequency (from 0.02 to 0.08) for the targeted loci. Identified point mutation g.124497381C greater than T was found to be significantly (p less than 0.05) associated with distance between teats and central ligament, SNP X: 124497248G greater than A with rear udder width, fore udder attachment, udder depth, udder length and teat length (p less than 0.05) and SNP X: 124497189 C greater than T with udder length and rear udder height (p less than 0.05). Interaction of identified SNPs and udder traits highlighted the gene’s potential as a candidate gene for selecting for conformation traits in Indian Sahiwal cattle.

Direct Phenotyping and Principal Component Analysis of Type Traits Implicate Novel QTL in Bovine Mastitis through Genome-Wide Association.

Simple SummaryIt is well established that the physical conformation of a cow’s udder and teats may influence her susceptibility to mastitis, an inflammatory condition of the udder, which has 25% prevalence in the United States. Our aim was to improve the biological understanding of the genetics underlying mastitis by intensively characterizing cows for udder and teat conformation, including the novel traits of teat width and end shape, and directly associating those phenotypes with high-density genotypes for those exact same cows. We also generated a composite measure that accounts for multiple high-mastitis-risk udder and teat conformations in a single index for risk phenotypes. Using this approach, we identified novel genetic markers associated with udder and teat conformation, which may be good candidates for inclusion in national genetic evaluations for selection of mastitis-resistant cows. Mastitis is the costliest disease facing US dairy producers, and integrating genetic information regarding disease susceptibility into breeding programs may be an efficient way to mitigate economic loss, support the judicious use of antimicrobials, and improve animal welfare.Our objectives were to robustly characterize a cohort of Holstein cows for udder and teat type traits and perform high-density genome-wide association studies for those traits within the same group of animals, thereby improving the accuracy of the phenotypic measurements and genomic association study. Additionally, we sought to identify a novel udder and teat trait composite risk index to determine loci with potential pleiotropic effects related to mastitis. This approach was aimed at improving the biological understanding of the genetic factors influencing mastitis. Cows (N = 471) were genotyped on the Illumina BovineHD777k beadchip and scored for front and rear teat length, width, end shape, and placement; fore udder attachment; udder cleft; udder depth; rear udder height; and rear udder width. We used principal component analysis to create a single composite measure describing type traits previously linked to high odds of developing mastitis within our cohort of cows. Genome-wide associations were performed, and 28 genomic regions were significantly associated (Bonferroni-corrected p < 0.05). Interrogation of these genomic regions revealed a number of biologically plausible genes whicht may contribute to the development of mastitis and whose functions range from regulating cell proliferation to immune system signaling, including ZNF683, DHX9, CUX1, TNNT1, and SPRY1. Genetic investigation of the risk composite trait implicated a novel locus and candidate genes that have potentially pleiotropic effects related to mastitis.

Genetic parameters for clinical mastitis in Czech Holstein cattle

Genetic parameters were estimated for clinical mastitis in Czech Holstein cattle. The datasets included 14 329 cows with 28 626 lactations. Clinical mastitis was defined as 0/1 occurrence per lactation. Single- or multi-trait repeatability linear animal models were employed for estimation of (co)variances and prediction of conventional or genomic breeding values. The inclusion of the random herd-year-month effect in the model was analysed. The estimated heritability for clinical mastitis ranged from 2.10% to 2.72%, while permanent environmental variance ratios or random herd-year-month effect ratios were twice higher than heritability. In the multi-trait models, udder type traits, such as fore udder attachment, rear udder attachment, rear udder width, front teat placement and udder depth, were employed. The highest genetic correlations of clinical mastitis occurred with rear udder width (0.41) and the lowest with front teat placement (–0.10). Both the multi-trait model and the genomic model provided breeding value estimates with higher reliability. In contrast, the model with random herd-year-season effects provided breeding values with lower accuracy.

WITHDRAWN:Principal component analysis of linear udder type traits and their relationship with milk yield and composition in indigenous Sahiwal cattle.

Ahead of Print article withdrawn by publisher.

Genetic parameters for linear type traits including locomotion in Italian Jersey cattle breed

This study aimed to estimate genetic parameters for 19 linear type traits related to frame, udder, and feet and legs, and for final score of 10,305 first-parity Jersey cows evaluated between 2004 and 2016. Since scoring of locomotion in Jersey breed started in 2009, a subset of 6853 animals was extracted from the original data and used to investigate sources of variation and heritability of locomotion score, and its associations with the other traits. Univariate animal models were used to estimate variance components of type traits and bivariate analyses were implemented to obtain genetic correlations between traits. Fixed effects were herd-year-classifier, season of evaluation, stage of lactation at scoring and age at calving, and the random effects were additive genetic animal and the residual. Herd-year-classifier was the major source of variation affecting the traits. Heritabilities were low with the only exception of a moderate heritability (0.32 ± 0.02) for stature. The lowest heritabilities were estimated for feet and legs traits with values between 0.04 ± 0.02 (rear leg set side view, rear leg set rear view and locomotion) and 0.07 ± 0.02 (foot angle). The final score had heritability of 0.20 ± 0.02. Genetic correlations were generally stronger than their phenotypic counterparts. Overall, frame traits were weakly correlated with feet and legs, and udder traits, except for rump width, which showed moderate correlations with almost all traits, and angularity which showed the greatest correlations with rear udder height (0.61 ± 0.10) and rear udder width (0.62 ± 0.11). Genetic correlations between locomotion and frame traits ranged from 0.08 ± 0.22 (angularity) to 0.32 ± 0.16 (stature). The strongest correlations were estimated between locomotion and other feet and legs traits, but also with front teat placement (0.97 ± 0.19) and with rear teat placement (0.88 ± 0.17). Results of the present study will be used to enhance genetic evaluation of linear type traits in Jersey cattle breed.

ЭКСТЕРЬЕРНЫЕ ПРИЗНАКИ АЙРШИРСКИХ КОРОВ РАЗНЫХ РЕГИОНАЛЬНЫХ ПОПУЛЯЦИЙ И ИХ СВЯЗЬ С МОЛОЧНОЙ ПРОДУКТИВНОСТЬЮ

The main selection and genetic parameters of the linear and classification traits of the exterior of 1,438 first calving cows of the Leningrad, Kirov and Vologda regions of the Russian Federation. Most variable indicators were cleft in all three populations (30.65; 36.67; 30.47 %) and in the Vologda and Leningrad populations - 35.57 and 23.40 %, respectively. The “rump width” in the Vologda population at Cv = 41.6% had a rather low absolute score (2.31 ± 0.08 points), therefore more careful selection is needed. The soft pasterns (26.8%), additional teats (26.2%), and slack back (8.3%) were the most common deficiencies. Less common were a peaked rump (6.2%), a high-set tail (4.8%), and a pterygoid scapula (4.1%). The construction of linear profiles of bulls Geyser, Lepa, Landskape using the standard transmission ability (STA) for each linear and classification types was carried out. The largest positive correlation values of the rear udder width (0.30, P≤0.001), front length udder (0.24, P≤0.001), body depth (0.12, P≤0.001) and dairy form (0, 10, P≤0,001). Reliability negative relationship between the corner rump and milk yield -0.09 (P≤0.001).

Udder and teat conformational risk factors for elevated somatic cell count and clinical mastitis in New York Holsteins

Our primary objective was to identify udder and teat conformational risk factors associated with the occurrence of elevated somatic cell count (SCC) and clinical mastitis using a prospective cohort study design with careful assessment of exposure and disease outcomes. Mastitis prevalence was evaluated by parity across 6 sampling periods representing key physiological transitions during lactation: 0–1 day in milk (DIM), 3–5 DIM, 10–14 DIM, 50–60 DIM, 90–110 DIM, and 210–230 DIM. Cows were scored for front and rear teat length, width, end shape, and placement, fore udder attachment, udder cleft, udder depth, rear udder height, and rear udder width. Two independent multivariable logistic regression models were used to generate odds ratios (OR) for elevated SCC (≥ 200,000 cells/ml) and farm-diagnosed clinical mastitis. We identified that loose fore udder attachment (reference level: strong fore udder attachment, OR = 2.1, 95% confidence interval (CI) = 1.2–3.8) and flat teat end shape (reference level: round teat end shape, OR = 1.4, 95% CI = 1.1–1.9) increased the odds of an elevated SCC event, whereas a negative California Mastitis Test score at 0–1 DIM decreased the odds of an elevated SCC event (OR = 0.6, 95% CI = 0.4 to 0.8). Loose fore udder attachment (reference level: strong fore udder attachment, OR = 3.7, 95% CI = 1.3–10.7), flat teat end shape (reference level: round teat end shape, OR = 1.5, 95% CI = 1.0–2.4), low rear udder height (reference level: intermediate rear udder height, OR = 2.8, 95% CI = 0.3–6.2), and increasing rear teat width (OR = 2.2, 95% CI = 1.2–4.4) heightened the odds of developing clinical mastitis. We identified that within our study cohort, loose fore udder attachment and flat teat ends had an important association with increased odds of both an elevated SCC event and clinical mastitis diagnosis. The identification of these udder and teat conformational risk factors for mastitis can provide farmers an effective and inexpensive tool to manage mastitis.

English

The traits of economic importance in farm animals are mostly controlled by many gene pairs and hence show correlations. The knowledge of such correlations is very much needed while making multiple traits selection in farm animals. The present study was planned with the objectives to find out genetic and phenotypic correlations between linear type traits and milk yield in Sahiwal cows. Freshly calved 310 cows were scaled and scored for traits on a linear scale of 1-9 following the guide lines of International Committee on Animal Recording. The variance and covariance components were estimated using residuals or restricted maximum likelihood (REML) procedures. The linear mixed model was fitted for estimation of variance. Bivariate animal model analysis was performed for estimation of genetic and phenotypic correlations. Stature, angularity, rear udder height, fore teat length, dewlap width, foot angle, udder depth and rear udder width were significant sources of variation for score-day milk yield (P<0.05-P<0.001). The 305-day milk yield was influenced by linear type traits of rump angle, rump width, central ligament and rear udder width (P<.05-P<.001). Highest positive genetic correlations were for rear udder width with score-day milk yield (0.43±0.00) and 305 days milk yield (0.40±0.00). The highest negative genetic correlation (-0.27±0.00 and -0.23±0.00) was found of udder depth with score-day milk yield and 305-day milk yield. The phenotypic correlations ranged from -0.23±0.06 between udder depth and score-day milk yield to 0.54±0.04 between rear udder width and score-day milk yield. The genetic and phenotypic correlations will help to short list the type traits and put focus on those that are more important. The linear scoring in Sahiwal cattle should be initiated at public and private farms.

Prediction possibility of milk yield from udder measurements using digital image analysis on holstein cows

A photographic survey of 43 multiparous lactating cows was carried out by recording the images between morning and evening milking time (around noon time) using digital camera from posterior angle. Images were then processed using Image Tools V.3.00 software to determine Udder measurements (UMs) of cows from the images in centimetres. The linear parameters recorded were rear udder depth (UD), rear udder width (UW) and rear udder area (UA). Regression analysis of milk yield on each of the independent variables was performed. Regression coefficients, for all UMs, taken together were 65.5%. The single regression coefficients were 23.0, 0.2 and 61.0for UD, UW and UA, respectively. The correlation coefficients between milk yield and UD, UW and UA were 0.48 (P >0.05), 0.04 (P >0.05) and 0.78 (P <0.05), respectively. The results showed that, the milk yieldof cows could be predicted using digital image, using udder area as a parameter. However, the prediction possibility was higher when all UMs were used.