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29 results on '"Cue, Roger I."'

9. The Impact of Selective Dry Cow Therapy Adopted in a Brazilian Farm on Bacterial Diversity and the Abundance of Quarter Milk

Author

Goncalves, Juliano L., primary, Young, Juliana, additional, Leite, Renata de F., additional, Fidelis, Carlos E., additional, Trevisoli, Priscila A., additional, Coutinho, Luiz L., additional, Silva, Nathália C. C., additional, Cue, Roger I., additional, Rall, Vera Lucia Mores, additional, and dos Santos, Marcos V., additional

Published
2022
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11. Molecular characterization of persistent subclinical mastitis-causing Staphylococcus aureusfrom dairy farms

Author

Gonçalves, Juliano Leonel, Lee, Sarah H. I., Camargo, Carlos H., Zanella, Rosemeire Cobo, Silva, Nathália C. C., Rall, Vera. L. M., Cue, Roger I., and dos Santos, Marcos V.

Abstract

The study aimed to evaluate the genetic diversity of Staphylococcus aureuscausing subclinical mastitis (SM) isolated from dairy cows and to assess the effect of the infection status (transient vs. persistent) on the milk and component yield. A total of six dairy farms in São Paulo state were used for the selection of cows with SM caused by S. aureus. S. aureusstrains (n= 56) obtained from three biweekly aseptic mammary quarter milk samplings (n= 1140 from 95 cows) were subjected to MALDI-TOF MS analysis for species confirmation and further PFGE analysis. Intramammary infections (IMI) caused by S. aureuswere categorized as transient (T: when only one out of 3 milk samplings had positive isolation of any pulsotype) or persistent (P: when two (P2) or three (P3) milk samplings had positive isolation of identical pulsotype over the consecutive episodes of SM. The SmaImacrorestriction fragment profiles of 56 S. aureusisolates showed a dominant S. aureusclonal pattern (PFGE type A; n= 50; 89.3%) within and among the herds. The SM-causing S. aureusrepresented a reduction of quarter milk yield of 26.2% in transient and 54.8% in persistent cases as well as a reduction of total solid yield of 38.1% and 49.4%, respectively, when compared with the healthy control quarters. Overall, the greater chance of S. aureusto be persistent is when a dominant clonal pattern is present in the herd which consequently may be associated with the cause of accentuated milk loss.

Published
2023
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23. A comprehensive integration of factors affecting vitamin B12concentration in milk of Holstein cows: genetic variability, milk productivity, animal characteristics, and feeding management

Author

Duplessis, Mélissa, Girard, Christiane L., Pellerin, Doris, Fadul-Pacheco, Liliana, and Cue, Roger I.

Abstract

Daily vitamin B12(VB12) requirements of humans can naturally be fulfilled by animal product consumption, especially products from ruminants because of bacteria dwelling in their rumen. Indeed, only bacteria can synthesize this vitamin. Milk is hence an excellent source of VB12. This cross-sectional study was undertaken to unravel factors, such as genetic variation, diet and cow characteristics, and milk production, explaining the large variation in milk B12concentration among cows by using an integrative approach. Milk samples from 2 consecutive milkings were collected from 3,533 Canadian Holstein cows (1,239 first, 932 s, and 1,362 third and more lactations) located in 99 herds with various feeding management. For genetic variation analysis purpose, pedigrees were traced back for 3 complete generations for each sire and dam. A total of 10,021 identities were used in the subsequent genetic analyses. Milk VB12averaged 4.2 ng/mL with a range between 0.7 and 9.0 ng/mL. Dietary fiber (NDF from forage, dietary NDF, ADF, and lignin) increased and dietary components related to energy (non-fiber carbohydrate, starch, net energy of lactation, and percentage of concentrate) decreased VB12in milk. Milk VB12varied with days in milk, with a similar pattern as milk fat and protein concentration lactation curves. Milk VB12increased as age at calving increased. When disregarding the herd variance, heritability value was 0.37, meaning that milk VB12can be modified by genetic selection. The final model including factors related to the diet, animal characteristics and milk productivity, and genetic variation explained 79% (pseudo-R2) of the milk VB12variation. When excluding the random effect of the cow, i.e., excluding the animal and genetic relationships, the pseudo-R2dropped to 43%, reinforcing the importance of genetic variation in explaining milk VB12variation. To our knowledge, the present study is the most comprehensive evaluation of factors affecting milk VB12variation including the greatest number of cows from various lactation stages.

Published
2024
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28. Impact of reproductive traits on productive life in Iranian Holstein dairy cows.

Author

Reisi‐Vanani, Reza, Ansari‐Mahyari, Saeid, Pakdel, Abbas, and Cue, Roger I.

Subjects
*DAIRY cattle, *LACTATION in cattle, *ANIMAL herds, *CATTLE fertility, *PROPORTIONAL hazards models, *CATTLE herding, *MILK yield
Abstract

Enhancing reproductive performance is a key strategy to mitigate involuntary culling rates, thereby extending productive life (PL) and ultimately improving profitability in dairy cattle herds. A piecewise Weibull proportional hazards model was used to investigate the effect of several important reproductive traits on PL in Holstein dairy cows. Data comprised 200,747 lactation records from 82,505 cows sired by 1952 bulls across 36 dairy herds. PL was defined as the number of days from the first calving to the last milk record or censoring. The statistical model accounted for the time‐dependent fixed effects of changes in herd size, year‐season, milk production, fat and protein contents, and the time‐independent fixed effect of age at first calving. Herd‐year and sire effects were also included as random effects. Reproductive traits include calving traits such as calving ease (CE), calf size (CZ), and calf survival (CS), as well as female fertility traits such as number of inseminations per conception (NI), days from calving to first service (CFS), days from first service to conception (FSC), and days open (DO). All reproductive traits had a significant effect on PL (p < 0.001). Each reproductive trait was analysed separately. The relative risk (RR) of being culled increased as the severity of calving difficulties increased in both primiparous and multiparous cows. Cows that calved small or large calves showed a higher risk of being culled compared with those that calved medium size calves. The increased RR of culling was observed only for primiparous cows that gave birth to dead calves. In addition, cows that required more NI, a longer CFS, FSC, and DO had shorter longevity. These insights can deepen our comprehension of the factors affecting PL and provide information for refining management and breeding strategies, which could lead to increased profitability and sustainability in Iranian dairy farming. [ABSTRACT FROM AUTHOR]

Published
2024
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29. Impact of Type Traits on Functional Herd Life of Quebec Holsteins Assessed by Survival Analysis.

Author

Schneider, M. del P., Dürr, J. W., Cue, Roger I., and Monardes, H. G.

Subjects
*MILK, *DAIRY industry, *CALVES, *HERDERS
Abstract

Survival analysis was used to study the effects of composite and descriptive linear type traits on functional herd life of Quebec Holsteins. Functional herd life was defined as the length of life from first calving to death, culling, or censoring, and was adjusted for 305-d milk production. The dataset contained information from 331, 105 cows from Quebec province calving for the first time between 1981 and 1995; 58% of the records had type information. Weibull models were fitted to analyze the data. The hazard function was described as the product of a baseline hazard function and the time-independent effects of age at first calving and type, and the time-dependent effects of year of calving, stage of lactation x lactation number, annual change in herd size, 305-d milk production, and herd-year (random). Analyses were done one at a time for each type trait. The strongest relationships between survival and composite type traits were found for final score, mammary system, and feet and legs. Among the linear type traits, the highest impact on functional herd life was found for traits related to the udder. [ABSTRACT FROM AUTHOR]

Published
2003
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