Milk samples from three Jersey and three Holstein herds were used to determine if the degree of churning correlated with the initial milkfat assay, and also to determine if the churned milkfat could be measured as accurately as the initial milkfat using the Milko-Tester. Regression lines for the initial milkfat test versus churned milk- fat test fit polynomial curves. The degree of churning was greater for Jerseys than Holsteins and correlated with the initial milkfat test. The repeatability of initial milkfat tests vas 0.98 for Jerseys and 0.99 for Holsteins. However, the repeatability of churned milkfat tests was lower for both breeds, especially for Jerseys. This indicated that the churned sample could not be measured for its milkfat content as accurately as the nonchurned sample. Churned milkfat samples all tested lower than initial milkfat samples, thus the Milko-Tester Mark III was unable to provide an initial fat test estimate following sample churning. Cows were different from each other in the difference between initia1 and churned milk fat tests. This suggested that cows which produce milk with a higher tendency for churning are apt to receive less reliable milkfat tests from central laboratories than other cows, when all milk samples are subjected to churning conditions.

Thesis (MScAgric)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Mastitis is the most prevalent and costly production disease of dairy cattle; hence mastitis incidence is a distinctly important trait in dairy cattle. The primary objective of the study was to determine the economic value, and develop a model for genetic prediction of clinical mastitis in South African Holstein cattle. These procedures are a prerequisite to including this trait in the breeding objective. The cost of clinical mastitis per incident was calculated as the sum of revenue loss due to discarded milk during the infection period and the associated treatment costs. Economic value (ZAR/incident) was calculated as the change in profit (increase in costs) resulting from a simulated marginal increase in mastitis incidence in an average herd. Average economic losses due to clinical mastitis were estimated at ZAR919.96/cow/year and the average incidence was 0.9cases/cow/year. The economic value of clinical mastitis was ‐ZAR1079.51/incident. A model for predicting estimated breeding values (EBVs) for clinical mastitis using somatic cell score (SCS), fore teat length (FTL), udder depth (UD) and rear udder height (RUH) was developed, using genetic (co)variances among these traits. Since EBVs for SCS, FTL, UD and RUH are routinely estimated under the national genetic evaluation programme, EBVs for clinical mastitis can be predicted from the model developed in the current study. Thus, the results of the study provide the basis for including clinical mastitis in the breeding objective for South African Holstein cattle. / AFRIKAANSE OPSOMMING: Mastitis is die mees algemeenste en duursteproduksie siekte wat voorkom by melkbeeste, daarom is die voorkoms van mastitis 'n belangrike eienskap in melkbeeste. Die primêre doel van die studie was om die ekonomiese waarde te bepaal, asook die ontwikkeling van 'n model vir genetiese voorspelling van kliniese mastitis in Suid‐Afrikaanse Holstein beeste. Hierdie prosedures is 'n voorvereiste vir insluiting van hierdie eienskap as ‘n teeldoelwit in seleksie programme. Die koste van kliniese mastitis per voorval is bereken as die som van die inkomste verlies weens melk weggegooi tydens die infeksie periode en die gepaardgaande koste vir die behandeling. Ekonomiese waarde (ZAR / voorval) is bereken as die verandering in wins (toename in koste) wat voortspruit uit 'n gesimuleerde marginale toename in mastitis voorkoms in 'n gemiddelde kudde. Gemiddelde ekonomiese verliese as gevolg van kliniese mastitis was beraam op ZAR919.96/koei/jaar en die gemiddelde voorkoms was 0.9gevalle/koei/jaar. Die ekonomiese waarde van kliniese mastitis was ‐ ZAR1079.51/geval. 'n Model vir die voorspelling van beraamde teelwaardes (EBV’s) vir kliniese mastitis is ontwikkel deur gebruik te maak van die ko‐variansies tussen die onderskeie eienskappe: somatiese sel telling (SST), voorspeen lengte (VSL), uier diepte (UD) en agter uier hoogte (AUH). Aangesien teelwaardes vir SST, VSL, UD en AUH gereeld beraam word onder die Nasionale genetiese evaluasie program, kan teelwaardes vir kliniese mastitis voorspel word vanuit die model wat ontwikkel is in die huidige studie. Dus verskaf die resultate van hierdie studie ‘n basis vir die insluiting van kliniese mastitis as ‘n teeldoelwit in seleksie programme van die Suid‐Afrikaanse Holstein beeste.

Thesis (PhD)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Improvement and selection of superior animals for longevity is a viable complimentary strategy for increasing functional longevity of Holstein dairy cattle. Genetic evaluation of animals for functional longevity is a prerequisite for improvement of the trait. This study was carried out to determine non-genetic factors that influence functional longevity in South African Holstein cattle, as well as to estimate genetic parameters for functional longevity, estimate sire breeding values, and to establish the contribution of conformation traits to the risk of cows being culled from dairy herds. Analyses were carried out using records of 166 222 daughters of 2 051 sires from 1 545 herds in six regions of South Africa. The regions were the Western Cape, Eastern Cape, Northern Cape, Free State, Kwa-Zulu Natal and the combined Gauteng & North Western Provinces. Data were analysed using a piecewise Weibull sire-maternal grandsire model in which the baseline hazard was assumed to change at 270 and 380 days in milk as well as at drying-off. The fixed effects model comprised of the time-independent effect of age at first calving, the combined time-dependent effects of region x year of calving, number of lactations x within-herd milk production class, year of calving x within-herd protein and year of calving x fat percentage production class. Model also had the combined time-dependent effect of herd size x annual herd size change. The random herd-year and sire effects were later included in the model for the estimation of sire and herd-year variance components. Analyses indicated a decline in the survival function, an indicator of functional longevity, among cows that calved for the first time in 2000, 2004 and 2008. Cows that delivered their first calf in 2000 had better survival functions that those that calved for the first time in 2004 and 2008. All fitted effects significantly contributed to the risk of a cow being culled from a herd. Within-herd milk production made the largest contribution to the risk of a cow being culled from a herd. Survival was best in the Northern Cape and worst in Eastern Cape. The risk of being culled was the highest for cows in the second stage of lactation (271- 380 days), when the entire lactation period was considered. High producing cows were more likely not to be culled from a herd than poor producing cows. Cows were more likely to be culled for low protein production percentage than within-herd fat production percentage. The risk of being culled was low for heifers calving at 20 to 25 months of age. The higher risk of culling among cows with multiple lactations indicated the culling policy of dairy farmers to retain a higher number of younger cows than older cows in herds. A decrease in herd size was indicative of a high culling rate. Effective heritability was 0.109. Breeding values ranged from 2.12 for the best cows to -4.80 for the worst cows. This implied that the best and the worst cows were 2.12 times and 4.80 more likely to be culled from herds than the average cow respectively. Genetic trends for functional longevity indicated a marginal decline in sire estimated breeding values. This corresponded with the phenotypic decline in the survivor function observed in cows that calved in 200, 2004 and 2008. All udder, rump, body, feet and leg type traits, with the exception of rear leg side, significantly influenced functional longevity. Farmers culled cows mainly of extremely poor type with a tendency to retain animals with poor to very good structure. Udder traits contributed the most to the risk of a cow being culled. Cows were more likely to be culled for poor scores received for rear teat placement, rear udder height and fore udder attachment, than for any of the other conformation type traits. The contribution of angularity to the risk of being culled was also high, indicating a preference for highly angular bodied cows. Conformation type traits can therefore be used as indicator traits for functional longevity in Holstein cattle, especially when selection and culling is done based on very poor scores for udder traits. The study indicated that genetic improvement in functional longevity can be achieved with the evaluation and selection of dairy sires. There is therefore a wide scope for including functional longevity in the selection objectives for South African Holstein cattle. There is a need to develop appropriate models to ensure that the national dairy industry can benefit from using a Weibull piecewise model. / AFRIKAANSE OPSOMMING: Die verbetering en seleksie van voortreflike diere vir langlewendheid is 'n lewensvatbare en aanvullende strategie vir die verhoging van die funksionele langlewendheid van Holstein melkbeeste. Die genetiese evaluasie van melkproduserende diere ten opsigte van hierdie eienskap is ʼn voorvereiste om verbetering in die eienskap moontlik te maak. Die studie is uitgevoer om nie-genetiese faktore wat die funksionele langlewendheid van Suid-Afrikaanse Holsteins beïnvloed te bepaal, om genetiese parameters vir langlewendheid en vaar teeltwaardes vir dié eienskap te bepaal en ook om die bydrae van bouvorm eienskappe tot die waarskynlikheid van koeie om uitgeskot te word, te bepaal. ʼn Databasis bestaande uit rekords van 166 222 dogters van 2 051 vaars, wat in ses streke in Suid-Afrika (Wes-Kaap, Oos-Kaap, Noord-Kaap, Vrystaat, KwaZulu-Natal en die gekombineerde Gauteng en Noord-Wes Provinsies) voorgekom het, is vir die studie gebruik. Data is ontleed met behulp van 'n stuksgewyse Weibull vader-moeder grootvader model, waarin die basislyn risiko aanvaar is om te verander op 270, 380 dae na kalwing en by afdroog van die melkkoeie. Die vaste effek model het die tyd-onafhanklike effek van ouderdom met eerste kalwing en die tyd-afhanklike effekte van streek en jaar van kalwing, aantal laktasies en binne-kudde melkproduksie klas, binne-kudde proteïen en vet persent produksie klasse volgens jaar van kalwing, asook die gekombineerde tyd-afhanklike effek van kuddegrootte en jaarlikse verandering in kudde grootte, ingesluit. Die ewekansige trop-jaar en vaar effekte is later opgeneem in die model vir bepaling van die vaar- en kudde-jaar variansie komponente. Ontledings het aangedui dat daar 'n algemene afname in die oorlewingsfunksie, wat ʼn aanduiding van funksionele langlewendheid is, was in koeie wat vir die eerste keer in 2000, 2004 en 2008 gekalf het. Koeie wat vir die eerste keer in 2000 gekalf het, het ʼn hoër waarde vir die oorlewingsfunksie gehad as koeie wat onderskeidelik in 2004 en 2008 gekalf het. Alle vaste effekte het betekenisvol tot die waarskynlikheid van ʼn koei om uitgeskot te word, bygedra. Binne-kudde melkproduksie het die grootste bydrae tot die waarskynlikheid van ʼn koei om uitgeskot te word, gemaak. Wanneer die totale laktasieperiode in ag geneem is, was daar gevind dat koeie wat in die tweede fase van laktasie (271-380 dae) die hoogste risiko ervaar het om uitgeskot te word. Hoë produseerders, wanneer hulle met lae produseerders vergelyk is, was minder geneig om uitgeskot te word. Koeie was meer geneig om uitgeskot te word vir lae proteïen produksie persentasie as binne-kudde vet produksie persentasie. Die waarskynlikheid om uitgeskot te word, was laag vir verse wat op ʼn ouderdom van 20 tot 25 maande gekalf het. Die hoër risiko van uitskot van koeie met veelvuldige laktasies het aangedui dat melkboere geneig was om meer jonger koeie te behou en ouer koeie uit te skot. ʼn Afname in kuddegrootte was aanduidend van ʼn hoë uitskotpersentasie. Die effektiewe oorerflikheid was 0.109, met teelwaardes wat van 2.12 vir die hoogste produserende koeie tot -4.80 vir die laagste produserende koeie, gewissel het. Hierdie waardes het dus aangedui dat hoë produseerders en swak produseerders onderskeidelik ʼn 2.12 en 4.80 groter kans gehad het om uitgeskot te kan word. Genetiese tendense vir funksionele langlewendheid het aangedui dat daar 'n marginale afname in vaar beraamde teelwaardes vir funksionele langlewendheid was. Dit het ooreengestem met die waargenome fenotipiese afname in die oorlewingsfunksie wat in 2000, 2004 en 2008 gekalf het. Alle bou-tipe eienskappe (uier, agterkwart, liggaam, voet en been), met die uitsondering van die agterbeen kant, het funksionele langlewendheid betekenisvol beïnvloed. Boere het koeie hoofsaaklik op uiters swak boutipe uitgeskot, met 'n neiging om diere wat as ʼn swak tot uiters goeie bouvorm geklassifiseer is, te behou. Uier eienskappe het die meeste tot die waarskynlikheid van ʼn koei om uitgeskot te word, bygedra. Koeie met ʼn lae gradering vir agterste speen plasing, agter-uier hoogte en voor-uier aanhegting se waarskynlikheid om uitgeskot te word, was groter. Die bydrae van hoekigheid tot die waarskynlikheid van ʼn koei om uitgeskot te word was hoog, wat ʼn aanduiding van ʼn voorkeur vir 'n baie growwe hoekigheid was. Bouvorm tipe eienskappe kan dus gebruik word as indikator eienskappe vir funksionele langlewendheid in Holstein melkbeeste, veral wanneer in ag geneem word dat die meeste melkboere seleksie op grond van swak gradering van uier eienskappe doen. Die studie het aangedui dat genetiese verbetering in funksionele langlewendheid teweeg gebring kan word met die evaluering en seleksie van Holstein vaars. Daar is dus ʼn geleentheid vir die insluiting van funksionele langlewendheid in die seleksie doelwitte vir Suid-Afrikaanse Holstein beeste. Daar is ʼn behoefte om toepaslike modelle te ontwikkel wat met die toepassing daarvan, sal verseker dat die plaaslike melkbedryf sal kan voordeel trek deur die gebruik van 'n stuksgewyse Weibull model benadering.

The aim of this thesis was to evaluate the parameters of the milk performance, reproduction indicators and health of Holstein cows that were raised on pasture. The data were obtained from 50 pure bred animals and its crossbreeds which had been grazed and the control group which was represented by 20 heifer which had been reared in stable. The evaluation of parameters was set on the first standardized lactation in the range of 240 to 305 days. The first lactation milk performance traits were: quantity of milk (kg), quantity and content of fat (kg; %), quantity and content of protein (kg; %). The fertility traits were: length of service period (days), insemination interval (days), age at first calving (days).

The work deals with the evaluation of selected effects on reproduction of Holstein cattle breeds. The aim of the study was to evaluate reproductive parameters (insemination index, insemination interval, period service, interim, pregnancy after the first insemination) in a selected group of dairy cows. These reproductive indicators were subsequently evaluated depending on genotype, performance level, lactation order and age at first calving and used synchronization methods. The evaluation took place at the Vřesce farm, belonging to company Rynagro a.s. 260 Holstein breed cows and their hybrids were included. The results showed that some reproductive indicators (insemination interval, service period and interim) of the monitored group of dairy cows were lower than the average of the Czech Republic. When evaluating the genotype effect on reproductive parameters, a highly significant effect (p<0.01) of genotype on insemination interval was found. Holstein breed cows had a 7-day higher insemination interval than other crosses. In evaluating the effect of daily milk yield was not proven statistically significant differences (p>0.05) in period servis and interim. Statistically significant differences (p<0.05) in insemination index, insemination interval and pregnancy after the first insemination were proven in the performance evaluation. The p-value of the global null hypothesis was close to 0.05 and no significant differences between the compared groups were demonstrated in the subsequent multiple comparison. The effect of the order of lactation on reproductive parameters was not proven (p>0.05). However, interesting results were found by the impact of age at first calving. There was a statistically highly significant difference (p<0.01) between the groups in the insemination interval and the interim and a statistically significant difference (p<0.05) between the groups in the service period. Cows with a first calving age 23 months had all of these indicators lowest, the highest values were found within cows with a first calving age of 28 months. After evaluating the correlation analysis, a significant effect of age at first calving on insemination interval (p<0.05; r=0.13), on interim (p<0.01; r=0.17) and period service (p<0.01; r=0.17). Synchronization methods were used in 125 cows and the overall success rate after this treatment was 47%. The most commonly used protocol was the Ovsynch method. The calculations based on the extension of the service period quantified the theoretical loss for the extended cycle of dairy cows. This loss is 7 030, - CZK per cow and takes into account the losses for milk and the unborn calf, not the cost of further insemination and treatment of cows.

Rearing heifers is one of the most important activities undertaken in the framework of the operation of dairy cattle farms. Corn silage and perennial forage crops are an important feed for livestock. During their production is important to follow all technological procedures starting from the selection of seed forage crops to quality covering the silo. Failure to observe technological processes leads to problems of poor fermentation process which results in poor feed, which immediately reflected on the animals. The aim of this thesis was to evaluate nutritive value of silages. The literature review processes the nutrition of the heifers in the agricultural cooperative Zemědělská Klučenice, a.s. It includes also the composition of the feed ration, the share of individual components and their nutrient composition. Agricultural cooperative owns modern technology. The result there were no deficiencies in feed rations and in hygiene. In the conclusion, the author suggests possible solutions improve.

This thesis deals with the influence of level of yield, causes putting out dairy cows from the breed and age at first calving on fertility and longevity of dairy cows of Holstein cattle in the agribusiness Agropodnik Košetice, a.s. Monitored indicators of dairy cows of Holstein cattle were the amount of milk in the first lactation in kg, functional longevity in kg of milk, functional longevity in days and the causes of elimination of dairy cows from the breed. From the results of monitored herd it can be concluded that prolongation of age at first calving will increase functional longevity in days statistically significantly. In contrast, there was not found statistically significant effect of age at first calving on functional longevity in kg of milk. Ascertained results of the monitored dairy herd did not confirm that increasing milk yields deteriorated reproductive indicators. The length of the service period was shortened statistically significantly with increasing the yield of milk in kg per one hundred days ((P 0,05), with the yield for the first entire lactation (P 0,001) and the order of lactation (P 0,001). In the monitored herd the dairy cows that were eliminated due to postpartum paresis (2570.70 days) reached the highest longevity and also reached the highest milk production for functional longevity in kg of milk (49,919.95 kg).

The aim of this thesis was the evaluation of selected factors on milking yield and longevity of the selected herd of dairy cows of Holstein cattle in the company Prima Agri a.s. There were monitored the indicators of dairy cows of Holstein cattle such as genotype, milk performance, the order of the lactation, the age of the first calving, the length of interim and of the service period, lifetime performance and reasons for elimination. The data were taken from the dairy cows whose first lactation was finished from January 1st to December 31 st 2016. 385 dairy cows were included to the monitoring. As for the genotype influence on milk performance, statistically significant difference was found out between the first and the fourth and the third and the fourth group on the level of significance (P<0,01). The effect of the age of the first calving on milk performance in kg of milk on first lactation wasn´t statistically provable (P>0,05). Statistically highly significant difference was found out by the effect of the order of the lactation on milk performance on the level of significance (P<0,01) between the groups of the first lactation and of the other groups of lactation. Statistically significant difference was found out between the 2nd lactation and the 4th and higher lactation on the level of significance (P<0,05). The effect of the genotype on the length of interim and the effect of the order of lactation on the length of interim weren´t statistically provable (P>0,05). The effect of genotype on length of the service period was statistically significant on the level of significance (P<0,01) between the group H2 and the group H3. Statistically significant difference (P<0,05) was found out between the groups H1 and H3, H1 and H4 and as well as between the groups H2 and R. The effect of the order of lactation on the length of service period was statistically highly significant on the level of significance (P<0,001) between the groups of the first lactation and of the other groups of lactation and between the groups of the second and fourth and higher lactation. The effect of the genotype of eliminated dairy cows on lifetime performance in kg of milk was statistically highly significant on the level of significance (P<0,001) between the groups H 1 and H2, H1 and H3, H2 and H3, H2 and R, H3 and R. An average number of eliminated dairy cows was 28,62 %. The biggest number of the eliminated dairy cows was on the grounds of fertility disorders and that is 35%. Longevity of the eliminated dairy cows was 2,7 lactation.

The diploma thesis dealt with the analysis, and evaluation of dairy performance and its correlation with reproductive rates of Holstein cattle. Milk cows which were kept in Měcholupy agricultural, Inc., Předslav were analyzed between 2013 - 2015. Th ecompany is located in the foothills of the Bohemian Forest (Šumava). It breeds cattle for milk as well as meat, and pigs. The company management is committed to achieve good levels of milk production. It pays constant attention to this issue, so the average performance has risen since 2013 from 8 726 kilograms of milk to 9 093 kg of milk per cow in 2015. Cows on the 4th and higher lactation reached the highest performance in 2015 9 649 kg of milk. As for the European Union who abolished milk quotas in 2015 and the situation on the milk market is still complicated by banning exports of milk powder to Russia (Russian annexation of the Crimea), the management´s effort has been to produce milk at the lowest possible cost. They keep trying to limit culling as much as possible, so that they solve the problem of mastitis and reproduction at the highest level. Each cow which is treated has an individual approach, as well as the animal husbandry has specific requirements for animal breeding company in terms of quality seed. The results showed that milk cows with other health problems were eliminated the most (38.6% per year from 2013 to 2015) and also the ones with metabolism disorders and problems with hooves. The mastitis issue is dealt with very effectively, so that it is not one of the major problems of the herd (7.24 % for 2013 -2015). Management seeks to eliminate the problem milk cow in the lowest age and conversely on contrary if the animal is healthy, they try to keep it in the herd as long as possible, because such an animal has the greatest economic effect. Reproductive rateis not too satisfactory, but the management has no interest in hormonal control of reproduction. Active search of rutting cows is preferred by nursing staff. They cooperate actively with animal breeders and require a delivery of the insemination doses according to their requirements for each for each cow

This thesis examines the influence of the level of rearing and age at first calving on performance and longevity of Holstein dairy cattle in the company ZD Krásná Hora nad Vltavou C. The quantity of milk per kg in the first lactation, functional longevity in kg of milk, functional longevity and longevity in days belong among the indicators observed by cows of Holstein cattle. The results of the monitored herds can be concluded that extension of age at first calving is statistically significant on the amount of milk in the first lactation, on functional longevity in kg of milk, on functional longevity and longevity in days. In contrast, no significant influence of the weight was elicited by observed indicators. The highest longevity in the monitored herd was achieved by the cows that were excluded for a difficult birth and also achieved the highest milk yield for functional longevity in kg milk and observation for the highest average in the number of lactations for life.