A longevidade é uma característica relacionada à lucratividade da atividade leiteira. Contudo, sua seleção em rebanhos de vacas Holandesas no Brasil ainda é pouco considerada. Objetivou-se determinar os fatores não genéticos que influenciam a longevidade funcional em vacas Holandesas no Brasil, bem como estimar os parâmetros genéticos e conhecer a contribuição das características de tipo e da contagem de células somáticas (CCS) sobre o risco relativo de descarte das vacas. Utilizou-se um modelo de riscos proporcionais Weibull estratificado. Os efeitos fixos foram independentes do tempo, como a idade ao primeiro parto, e dependentes do tempo, como o efeito da região por ano de parto, classes de produção de leite por ano de parto dentro de rebanho, classes de percentagem de proteína e gordura dentro de rebanho, classes de produção de leite por número de lactações dentro de rebanho e variação nas classes de tamanho de rebanho. Os efeitos aleatórios foram: rebanho-ano, touro e de touro-avô materno. O risco de descarte aumentou com a idade ao primeiro parto, com o tamanho do rebanho, com o número de lactações e com o estágio de lactação. A produção de leite apresentou maior efeito sobre o risco de descarte. Vacas de baixa produção de leite, gordura e proteína apresentaram maior probabilidade de descarte em comparação à classe mediana. Vacas pertencentes às regiões do Paraná e São Paulo permaneceram mais tempo no rebanho do que as vacas de outras regiões. Os valores de h² variam de 7,8% a 6,1% para a h² equivalente e a efetiva, respectivamente. Observou-se tendência genética positiva para a longevidade. As características de tipo, escore final, angularidade, nivelamento da linha superior, textura do úbere e ligamento suspensório foram as características que se apresentaram mais relacionadas com a longevidade funcional. Foram observadas diferenças no risco de descarte dependendo do número de vacas classificadas para tipo dentro de rebanho. Até a 4ª lactação, o risco de descarte foi menor para vacas com baixa CCS em comparação a vacas da classe mediana. Já para vacas na 5ª lactação, a alta CCS conduziu ao menor risco de descarte. A rotina de avaliação genética é necessária para melhorar a duração da vida produtiva de vacas da raça Holandesa no Brasil. Características preditivas, tais como escore final, angularidade, nivelamento da linha superior, textura do úbere, ligamento suspensório e a CCS podem ser utilizadas para aumentar a confiabilidade dos valores genéticos dos touros para longevidade funcional. / Longevity is a trait related to the profitability of dairy activity. However, its selection in Brazilian Holstein herds is still little considered. The aim of this study was to determine the non-genetic factors that influence functional longevity in Holstein cows in Brazil, as well as to estimate the genetic parameters and the contribution of somatic cell score (SCS) and type traits on the relative culling risk of cows. A piecewise Weibullproportional hazard model was used. The fixed effects were time-independent, as age at first calving, and time-dependent, as the interaction effects of region by year of calving, milk production class by year of calving within herd, within herd milk production class by lactation number, within herd fat and protein content, and variation in herd size class. The random effects were herd-year effect, additive genetic contribution from the sire and maternal grandsire of the cow. The relative risk increased with age at first calving, lactation number by stage of lactation, and herd size but lower risks were observed when herd size was increasing or decreasing, compared to stable herds. Milk production had a greater effect on the risk of culling. The relative risk increased as milk production, protein and fat decreased, but to a lesser extent for protein and fat compared to milk yield. Cows from Paraná and São Paulo regions remained longer in the herd than cows from the other regions. The h² values varied from 7.8% to 6.1% for equivalent and effective h², respectively. A positive genetic trend of functional longevity was observed. The type traits, final score, angularity, top line, udder texture and suspensory ligament showed the strongest relationship with productive life. Differences in risk of culling were observed depending on the fraction of type-scored animals within a herd. The absence of type trait phenotypes was associated with a strong increase of culling risk for the cows. The impact of SCS on longevity was high in cows from 1st to 4th lactation with high SCS. Interestingly, for 5th lactation, cows with lower SCS have higher culling risk compared to cows with higher SCS. A routine of genetic evaluation is necessary to improve length of productive life of Brazilian Holsteins under local conditions. The use of early predictors correlated with longevity, as final score, angularity, top line, udder texture, suspensory ligament and SCS, may be recommended to increase the reliability of sires’ estimated breeding values for functional longevity.

According to the USDA Economic Research service, farm-level prices are on the decline. This decline in prices particularly hurts smaller scale operators with many needing to rely on off-farm income in order to ensure they remain in operation. This thesis studies two problems of key interest to the Southeast region and the State of Kentucky by investigating dairy management practices and the environmental benefits of hemp production. As dairy prices have been on the decline and dairy co-ops have tightened their restrictions on somatic cell count (SCC) levels, dairy farmers and farm managers must decide the best course of action for maintaining milk quality in order to maintain their contract and profitability. Maintenance decisions as well as factors like sanitation and animal living conditions can all contribute to bulk tank SCC and depending on the type of incentives or penalties instituted by the co-op they can have an impact on net farm income. The objective of the dairy study is to determine which dairy management practices have the largest impact on SCC levels. Industrial hemp is produced worldwide. Historically, the major producers of hemp have been China, Europe, and Russia. In 2014, the passage of the Farm Bill opened the door to the production of Industrial hemp through the development of state pilot programs. Then the 2018 Farm Bill removed industrial hemp from the Scheduled Drug list. This has further expanded the opportunities and excitement for this crop. The plant’s versatility and the variety of products that can be made from it are coming to light. Sustainability is one of the key attributes touted concerning industrial hemp. Specifically, in the state of Kentucky, it is expected to be a replacement for tobacco and other traditional crops. However, how does the crop compare to tobacco production in terms of sustainability? The objective of the hemp study is to develop a life cycle analysis on the planting and harvesting of hemp and compare its impacts to more traditional crops.

Embryos derived by somatic cell nuclear transfer (SCNT) produce few pregnancies that result in a live, healthy offspring. This has largely been attributed to the aberrant reprogramming of the somatic cell DNA used for cloning. In order to improve the efficiency of cloning there is a great deal of research needed to determine the role of proteins involved in early embryonic reprogramming. In addition, studies are needed to determine effects on somatic and embryonic cell development as a result of altering these proteins. In this study we investigate the use of RNA interference in bovine somatic cells and embryos to knock down the expression of DNA methyltransferase-1 (DNMT1), an enzyme responsible for maintenance methylation in mammalian cells. We designed our experiments to test whether or not knocking down the DNMT1 gene would lead to a decrease in global methylation. It is our hypothesis that using somatic cells with reduced methylation may be advantageous for increasing the efficiency of cloning via somatic cell nuclear transfer. To accomplish this task, we have designed an infectious non-replicating lentiviral vector capable of delivering a gene that produces a short hairpin RNA targeting the mRNA of DNMT1. The construct included a sequence coding for green fluorescent protein (GFP) that will allow us to identify cells expressing the hairpin as well as a region coding for neomycin resistance so we could select for a pure population of transgenic cells to use for analysis. Infecting bovine fetal fibroblast cells with genes encoding shRNAs that target DNMT1 was successful. Quantitative real time PCR analysis of DNMT1 mRNA suggests that our shRNAs are capable of an 80% knockdown. The protein blot of indicates up to 90% knockdown of DNMT1. Cells transduced twice with a high titer virus showed the highest knockdown of both DNMT1 mRNA and the protein. Analysis of immunolabeled cytosine methylaiton showed a global decrease in DNA methylation as a result of the DNMT1 knockdown. However, double transduced cells with a high knockdown percentage of DNMT1 mRNA and protein became hypermethylated. The second experiment was conducted to determine the effect of injecting small interfering RNAs (siRNAs) targeting DNMT1 into oocytes prior to parthenogenic activation. This experiment was designed to give us information on the survivability and epigenetic profile of early embryos with decreased DNMT1. Oocytes injected with siRNA targeting DNMT1 had little development past the 8-cell stage as compared to the sham injected oocytes. This treatment group also had decreased DNA methylation as determined by immunolabeling of methylated cytosine residues.

Research data show that the somatic cell count increases during the transition period when dairy cows are transferred from barns to pastures (month of May) and during the transition period when dairy cows are transferred from pasture to barn (month of October). During these period’s feedstuff composition changes, as does the temperature, microclimate parameters, which also have an influence on cows with Sub-clinical mastitis. Somatic cell counts are lowest in 1st lactation cows. 1st lactation cow somatic cell count in milk was 440,000 ± 66,400 cells/ml (2004) and 326,000 ± 55,500 cells/ ml (2005). Later lactation’s cow somatic cell counts in milk is higher, however the highest cow somatic cell count in milk is in 5th and upward lactations. Reproduction is usually evaluated during the span of the service period, taking into account the animal’s age at 1st parturition, its fertilisation index, timeframe between parturitions, and duration of pregnancy. These are important herd reproduction traits. Due to disorders in reproduction functions, costs of fertilisation increase and economic losses are sustained (Borman, 2006). The cow’s age at 1st parturition affects the heifer’s rate of maturity which also depends on the husbandry conditions and breed. During 2003 – 2004, the average age of 1st parturition Lithuanian Black/White breed cows was 26.7 - 32.6 months (Republic of Lithuania, Ministry of Agriculture, 2005). An early 1st parturition age (up to 23 months) is followed by a... [to full text]

Mastitis causes largest economic losses in dairy production. Sub-clinical mastitis is detected in 50% of lactating cows in Lithuania. Curing effect is transient if major causes and factors of mastitis are not eliminated. Prophylactic measures are directed to strengthen the immune system of the cow and to define and to eliminate all factors causing mastitis. Bacteria are present on skin of the teat in the surroundings. Use of antiseptics of cow teats before and after milking is the most effective preventive procedure that can prevent from new mastitis cases. Antiseptic solutions help to fight most opportunistic and contagious bacterial infections causing mastitis. Teat antiseptics can reduce mastitis incidence by 50 to 75 %. It is recommended to use antiseptic solutions for udder and teats, as they improve physical condition of the udder and milk quality. Agents for udder and teat antiseptics contain bactericidal, skin protecting components in aqueous solution. Bactericidal activity is defined to kill germs during chemical and biological reactions. Active ingredients are iodoforms, chlorhexidins, sodium hypochloride, sodium chloride, lactic acid, hypochloric acid, antimicrobial proteins and fatty acids. Teat dipping reduces bacterial milk contamination, and spreading of pathogens on the teats during the milking. For the present moment this procedure is also used in Europe. Spraying teats with two different concentrations of iodine solution before and after the milking... [to full text]

Pieno kokybę apibūdina visa eilė rodyklių. Svarbiausias iš jų - somatinių ląstelių skaičius. Didėjantis SLS nurodo, kad karvė serga dažniausiai pasitaikančia ginekologine liga mastitu. Klinikiniu mastitu serga apie 1 – 2 proc. karvių. Dažniausiai serga karvės slaptuoju mastitu. Literatūros duomenys teigia, kad laktuojančių karvių bandose šiuo mastitu serga 43 – 47 proc. karvių. Svarbiausias slaptojo mastito požymis-padidėjęs somatinių ląstelių skaičius piene. Dažniausiai tešmens infekcija karvės suserga pirmaisiais laktacijos mėnesiais ir 80 proc. atvejų jos serga visą laktacijos laikotarpį. Sergant mastitu netenkama iki 25 proc. pieno per laktaciją. Vien tik dėl vieno tešmens ketvirčio uždegimo pieno per laktaciją sumažėja net iki 12 proc. Mastitu persirgusių karvių produktyvumas ne visuomet atsikuria toks, koks buvo iki ligos, nes negrįžtamai pasikeičia alveolinis audinys, tad kai kurias karves tenka išbrokuoti. Mastitą galima diagnozuoti pagal laktozės koncentracija elektrolitų sudėti ir SLS. Patogiausia ir pigiausia diagnozuoti pagal SLS. / The aim of this study was to find the non genetical influence facts in cows milk, for healthy cows and cows with secret mastitis. Scientific research work was carried out at the Department of Non-infectious diseases, Lithuanian Veterinary Academy and Practical Instruction and Research Centre LVA from 2005 to 2007. This work analyses data from dairy cow milk production. Experiments were carried out on two to seven year old black and white breed lactating cows, during the housing period. Data from 166 cows was used in this analysis. Inclusion criteria - somatic cell count higher than 400x 103/ml. We analyzed the influence of lactation on milk somatic cell count, cow age impact on productivity during lactation period on the number of somatic cells in the milk, parturition – to conception period length, season of the year. Increasing lactation number, was associated with elevated somatic cell count from 247, 3 until 392, 4 103/ml; and average milk yield per day also increased from 12,1 until 13,8 kg, milk fat increased from 4,34 until 4,38 percent, protein content increased from 3,15 to 3,30 percent. Milk lactose content decreased accordingly from 4,75 to 4,67 percent. Age positively influences milk productivity. This can be explained by lowered resistance to mastitis which is more frequent with age, cow automatic milking and supervision mistakes (Powell, et Al. 1997). According to literature data age and lactation period highly influences cow health and productivity. Age has... [to full text]

Modernios pienininkystės fermos sėkmė priklauso nuo to, ar joje gaminamas pienas yra aukštos kokybės. Pagrindiniai veiksniai, turintys įtakos somatinių ląstelių skaičiui piene, yra gera melžimo organizacija, melžimo įrangos taisyklingas veikimas, klinikinių mastitų gydymas antibiotikais ir kt. Mokslininkai įrodė, kad melžti karves kas dvylika valandų yra optimaliausia, kai jos melžiamos du kartus per parą. SLS piene daug priklauso nuo taisyklingos melžimo darbotvarkės, kuri apima skirtingas melžimo operacijas (tešmens ir spenių paruošimas melžimui, spenių dirginimas, pirmųjų pieno čiurkšlių numelžimas, melžiklių užmovimas ant spenių, melžiklių numovimas pamelžus ir efektyvi spenių antiseptika po melžimo) ir nuo šių operacijų trukmės. Teisingai atliekamos melžimo procedūros yra svarbios mastito prevencijai ir užtikrina visišką pieno išmelžimą iš tešmens. Tyrėjai įrodė, kad daugiau kaip 50 % melžimo proceso laiko užtrunka pats melžimas. Dabartiniu metu melžimo operacijos vis labiau mechanizuojamos. Netaisyklingas melžimas gali pailginti pieno atleidimo laiką, didėja rizika susirgti tešmens uždegimais. Pablogėja pieno kokybė, todėl gaunami ekonominiai nuostoliai. Padidėjęs somatinių ląstelių skaičius piene ¬ svarbus mastito požymis. Perdirbamajai pramonei karvių mastitas buvo ir liks vienu iš svarbiausių trukdžių gaminant aukštos kokybės pieno produktus. Klinikine forma serga 2 – 5 % laktuojančių ir užtrūkintų karvių, o slaptuoju uždegimu – iki 50 % karvių. Viena dažniausiai... [toliau žr. visą tekstą] / Data were collected from two dairy farms. On the farm A cows were milked using full automatised milking equipment „Milkmaster“. On the farm B cows were milked with „Interpuls“ milking equipment. The DeLaval milking system was supplied with automatic cluster remover. On dairy farms A and B cows were milked twice daily. The goal of our studies was to analyse consumption of main milking operations (cow udder preparation before milking, milking and over-milking) and their influence on milk somatic cell count. Were selected 20 cows in each farm. The duration of main milking procedures were recorded. Data on milk, fat and protein yields and somatic cell count were collected.The mean duration of pre-milking udder preparation was 42 s (farm A) and 46,03 s (farm B). Some cows were prepared only for 25,50 Afarm A) s, whereas the udder preparation comprised merely inadequate cleaning of teats. The maximum duration of over-milking was 41,10 (farm B).

Šio darbo tikslas - palyginti skirtingų veislių karvių melžimo savybes. Darbo uždaviniai. 1. Išanalizuoti Lietuvos juodmargių ir Lietuvos žalųjų veislių karvių melžimo savybes. 2. Nustatyti laktacijos įtaką karvių melžimo savybėms. 3. Nustatyti melžimo laiko įtaką tiriamų veislių karvių pieno kiekiui ir vidutiniam pieno atidavimo greičiui. 4. Įvertinti ūkio įtaką melžimo savybėms. 5. Atlikti somatinių ląstelių skaičiaus (SLS) ir melžimo savybių koreliacinę analizę. Išvados: 1) Išanalizavus tirtų Lietuvos juodmargių ir Lietuvos žalųjų veislių karvių pagrindinių melžimo savybių rezultatus nustatyta, kad: 1.1. Vidutinis pieno tekėjimo greitis Lietuvos žalųjų (0,02 kg/min) buvo didesnis nei Lietuvos juodmargių veislės karvių (p<0,05). 1.2. Didžiausia pieno tekėjimo srovė buvo Lietuvos juodmargių buvo 0,05 kg/min didesnė nei Lietuvos žalųjų (p>0,05). 1.3. Melžimo laikas 0,11 min. buvo ilgesnis Lietuvos žalųjų veislės karvių. 2) Atlikus skirtingų laktacijų karvių produktyvumo ir melžimo savybių analizę, nustatyta, kad I laktacijos karvių bendras pieno kiekis (kg) ir vidutinis pieno atidavimo greitis (kg/min). buvo didžiausias Lietuvos žalųjų karvių, tačiau I laktacijos karvių melžimo trukmė buvo ilgesnė nei Lietuvos juodmargių veislės karvių. 3) Nustatyta, kad Lietuvos juodmargių, kurios melžėsi ilgiau nei 6 minutes buvo 4,73% daugiau nei Lietuvos žalųjų veislių karvių (p<0,05) Iš pateiktų duomenų matome, kad Lietuvos žalųjų buvo beveik 5% daugiau nei Lietuvos juodmargių, kurios... [toliau žr. visą tekstą] / The aim of this thesis was to assess milking properties of cows of different breeds. Objectives of the paper: 1. Analyze the Lithuanian Black and White and Lithuanian Red cows milking qualities. 2. Determine lactation influence milking performance. 3. Determine the time of milking cows tested influence on milk yield and milk the average speed of the output. 4. To evaluate the farm impact of the milking properties. 5. Perform somatic cell count and milking performance correlation analysis. The scientific research was carried out between 2012-2014 at the Department of Animal Breeding of the Veterinary Academy of the Lithuanian University of Health Sciences and 2 dairy farms. Descriptive statistics: the average of investigated traits (M), standard errors were calculated using the EXEL and “R” (The R Project for Statistical Computing, 2012) statistical packages Milking properties were analyzed with the help of the device Lactocorder. In total 81 cows of Lithuanian black and white and Lithuanian red cattle breeds from two farms were analyzed. Lithuanian black and white cows constituted 71.6 percent, while Lithuanian red cows constituted 28.4 percent. According to lactation all analyzed cows were divided into the following three groups: lactation I, lactation II, lactation III and later. The first lactation cows constituted 6.1 % , the second lactation cows constituted 19.75 % and the group of cows of the third and later lactation was the largest and constituted 74.07 % . The... [to full text]

A longevidade é uma característica relacionada à lucratividade da atividade leiteira. Contudo, sua seleção em rebanhos de vacas Holandesas no Brasil ainda é pouco considerada. Objetivou-se determinar os fatores não genéticos que influenciam a longevidade funcional em vacas Holandesas no Brasil, bem como estimar os parâmetros genéticos e conhecer a contribuição das características de tipo e da contagem de células somáticas (CCS) sobre o risco relativo de descarte das vacas. Utilizou-se um modelo de riscos proporcionais Weibull estratificado. Os efeitos fixos foram independentes do tempo, como a idade ao primeiro parto, e dependentes do tempo, como o efeito da região por ano de parto, classes de produção de leite por ano de parto dentro de rebanho, classes de percentagem de proteína e gordura dentro de rebanho, classes de produção de leite por número de lactações dentro de rebanho e variação nas classes de tamanho de rebanho. Os efeitos aleatórios foram: rebanho-ano, touro e de touro-avô materno. O risco de descarte aumentou com a idade ao primeiro parto, com o tamanho do rebanho, com o número de lactações e com o estágio de lactação. A produção de leite apresentou maior efeito sobre o risco de descarte. Vacas de baixa produção de leite, gordura e proteína apresentaram maior probabilidade de descarte em comparação à classe mediana. Vacas pertencentes às regiões do Paraná e São Paulo permaneceram mais tempo no rebanho do que as vacas de outras regiões. Os valores de h² variam de 7,8% a 6,1% para a h² equivalente e a efetiva, respectivamente. Observou-se tendência genética positiva para a longevidade. As características de tipo, escore final, angularidade, nivelamento da linha superior, textura do úbere e ligamento suspensório foram as características que se apresentaram mais relacionadas com a longevidade funcional. Foram observadas diferenças no risco de descarte dependendo do número de vacas classificadas para tipo dentro de rebanho. Até a 4ª lactação, o risco de descarte foi menor para vacas com baixa CCS em comparação a vacas da classe mediana. Já para vacas na 5ª lactação, a alta CCS conduziu ao menor risco de descarte. A rotina de avaliação genética é necessária para melhorar a duração da vida produtiva de vacas da raça Holandesa no Brasil. Características preditivas, tais como escore final, angularidade, nivelamento da linha superior, textura do úbere, ligamento suspensório e a CCS podem ser utilizadas para aumentar a confiabilidade dos valores genéticos dos touros para longevidade funcional. / Longevity is a trait related to the profitability of dairy activity. However, its selection in Brazilian Holstein herds is still little considered. The aim of this study was to determine the non-genetic factors that influence functional longevity in Holstein cows in Brazil, as well as to estimate the genetic parameters and the contribution of somatic cell score (SCS) and type traits on the relative culling risk of cows. A piecewise Weibullproportional hazard model was used. The fixed effects were time-independent, as age at first calving, and time-dependent, as the interaction effects of region by year of calving, milk production class by year of calving within herd, within herd milk production class by lactation number, within herd fat and protein content, and variation in herd size class. The random effects were herd-year effect, additive genetic contribution from the sire and maternal grandsire of the cow. The relative risk increased with age at first calving, lactation number by stage of lactation, and herd size but lower risks were observed when herd size was increasing or decreasing, compared to stable herds. Milk production had a greater effect on the risk of culling. The relative risk increased as milk production, protein and fat decreased, but to a lesser extent for protein and fat compared to milk yield. Cows from Paraná and São Paulo regions remained longer in the herd than cows from the other regions. The h² values varied from 7.8% to 6.1% for equivalent and effective h², respectively. A positive genetic trend of functional longevity was observed. The type traits, final score, angularity, top line, udder texture and suspensory ligament showed the strongest relationship with productive life. Differences in risk of culling were observed depending on the fraction of type-scored animals within a herd. The absence of type trait phenotypes was associated with a strong increase of culling risk for the cows. The impact of SCS on longevity was high in cows from 1st to 4th lactation with high SCS. Interestingly, for 5th lactation, cows with lower SCS have higher culling risk compared to cows with higher SCS. A routine of genetic evaluation is necessary to improve length of productive life of Brazilian Holsteins under local conditions. The use of early predictors correlated with longevity, as final score, angularity, top line, udder texture, suspensory ligament and SCS, may be recommended to increase the reliability of sires’ estimated breeding values for functional longevity.

A longevidade é uma característica relacionada à lucratividade da atividade leiteira. Contudo, sua seleção em rebanhos de vacas Holandesas no Brasil ainda é pouco considerada. Objetivou-se determinar os fatores não genéticos que influenciam a longevidade funcional em vacas Holandesas no Brasil, bem como estimar os parâmetros genéticos e conhecer a contribuição das características de tipo e da contagem de células somáticas (CCS) sobre o risco relativo de descarte das vacas. Utilizou-se um modelo de riscos proporcionais Weibull estratificado. Os efeitos fixos foram independentes do tempo, como a idade ao primeiro parto, e dependentes do tempo, como o efeito da região por ano de parto, classes de produção de leite por ano de parto dentro de rebanho, classes de percentagem de proteína e gordura dentro de rebanho, classes de produção de leite por número de lactações dentro de rebanho e variação nas classes de tamanho de rebanho. Os efeitos aleatórios foram: rebanho-ano, touro e de touro-avô materno. O risco de descarte aumentou com a idade ao primeiro parto, com o tamanho do rebanho, com o número de lactações e com o estágio de lactação. A produção de leite apresentou maior efeito sobre o risco de descarte. Vacas de baixa produção de leite, gordura e proteína apresentaram maior probabilidade de descarte em comparação à classe mediana. Vacas pertencentes às regiões do Paraná e São Paulo permaneceram mais tempo no rebanho do que as vacas de outras regiões. Os valores de h² variam de 7,8% a 6,1% para a h² equivalente e a efetiva, respectivamente. Observou-se tendência genética positiva para a longevidade. As características de tipo, escore final, angularidade, nivelamento da linha superior, textura do úbere e ligamento suspensório foram as características que se apresentaram mais relacionadas com a longevidade funcional. Foram observadas diferenças no risco de descarte dependendo do número de vacas classificadas para tipo dentro de rebanho. Até a 4ª lactação, o risco de descarte foi menor para vacas com baixa CCS em comparação a vacas da classe mediana. Já para vacas na 5ª lactação, a alta CCS conduziu ao menor risco de descarte. A rotina de avaliação genética é necessária para melhorar a duração da vida produtiva de vacas da raça Holandesa no Brasil. Características preditivas, tais como escore final, angularidade, nivelamento da linha superior, textura do úbere, ligamento suspensório e a CCS podem ser utilizadas para aumentar a confiabilidade dos valores genéticos dos touros para longevidade funcional. / Longevity is a trait related to the profitability of dairy activity. However, its selection in Brazilian Holstein herds is still little considered. The aim of this study was to determine the non-genetic factors that influence functional longevity in Holstein cows in Brazil, as well as to estimate the genetic parameters and the contribution of somatic cell score (SCS) and type traits on the relative culling risk of cows. A piecewise Weibullproportional hazard model was used. The fixed effects were time-independent, as age at first calving, and time-dependent, as the interaction effects of region by year of calving, milk production class by year of calving within herd, within herd milk production class by lactation number, within herd fat and protein content, and variation in herd size class. The random effects were herd-year effect, additive genetic contribution from the sire and maternal grandsire of the cow. The relative risk increased with age at first calving, lactation number by stage of lactation, and herd size but lower risks were observed when herd size was increasing or decreasing, compared to stable herds. Milk production had a greater effect on the risk of culling. The relative risk increased as milk production, protein and fat decreased, but to a lesser extent for protein and fat compared to milk yield. Cows from Paraná and São Paulo regions remained longer in the herd than cows from the other regions. The h² values varied from 7.8% to 6.1% for equivalent and effective h², respectively. A positive genetic trend of functional longevity was observed. The type traits, final score, angularity, top line, udder texture and suspensory ligament showed the strongest relationship with productive life. Differences in risk of culling were observed depending on the fraction of type-scored animals within a herd. The absence of type trait phenotypes was associated with a strong increase of culling risk for the cows. The impact of SCS on longevity was high in cows from 1st to 4th lactation with high SCS. Interestingly, for 5th lactation, cows with lower SCS have higher culling risk compared to cows with higher SCS. A routine of genetic evaluation is necessary to improve length of productive life of Brazilian Holsteins under local conditions. The use of early predictors correlated with longevity, as final score, angularity, top line, udder texture, suspensory ligament and SCS, may be recommended to increase the reliability of sires’ estimated breeding values for functional longevity.