Calf health data and first lactation records for 2556 cows born in a commercial dairy herd between June 1998 and June 2001 were studied to determine the effects of calfhood disease on survival and performance. Operator-treated respiratory disease occurrences within the first year of life and digestive disease occurrences within the first 45 d of life were analyzed to determine their effects on calfhood morbidity, age at first calving, 305-d first lactation production, and mortality in first lactation. Of the 2556 records used, 2083 calves contracted respiratory or digestive disease at least once, 1254 calves had digestive disease only, 771 had respiratory disease only, and 191 calves had both diseases. Occurrence of calfhood digestive disease increased the chance of calfhood respiratory disease 2-fold. Age at first calving increased 0.53 mo with multiple occurrences of respiratory disease versus none. Calves born in the winter calved at 25.4 mo, whereas calves born in spring calved at 24.5 mo. Respiratory disease had the largest effect on calves born in the spring, resulting in 23.9 mo age at first calving for no occurrence and 25.4 mo for multiple occurrences. No significant effect of disease was detected for 305-d milk yield, fat yield, or SCC, but protein yield decreased by 0.05 kg/d with increased calf respiratory disease. Although calfhood disease had no influence on illness as a cow, disease-free calves had a 5% advantage in probability of remaining in the herd through 305-d, and an 8% advantage at 730-d compared with calves with 2 or more disease occurrences. In conclusion, calfhood occurrences of respiratory and digestive disease had a slight impact on age at first calving, depending on season of birth, and minimal impact on production performance through 305-d of first lactation. The occurrence of respiratory or digestive disease caused a decrease in survival rate from calving through 305-d in first lactation and 730 d after calving. / Master of Science

Master of Science / Department of Animal Sciences and Industry / Daniel W. Moser / The purpose of this study was to estimate the heritability of calving rate and age at first calving in Hereford heifers, and evaluate whether age at calving would add accuracy to a genetic evaluation of calving rate. Pedigree and performance data on Hereford heifers born between 2001 and 2007 was provided by the American Hereford Association. After editing to exclude animals that did not fit inclusion criteria, the evaluated dataset contained 94,709 heifers with calving status information. Data were analyzed using single and two-trait animal models to obtain heritability estimates, and genetic correlation between calving rate and age at first calving was determined using MTDFREML. Contemporary groups for calving traits were defined as heifers that were in the same yearling weight contemporary group, and remained in the ownership of the same breeder through the age that they would be expected to calve. Estimates of heritability for calving rate and age at first calving from single-trait models were 0.25, and 0.12, respectively. Genetic correlation between calving rate and age at first calving was -0.01. Calving rate is moderately heritable in Hereford heifers, and can be used in genetic evaluation of sires to improve the trait through selection. Age at first calving has minimal genetic relationship to calving rate, and is not useful in increasing accuracy of selection for calving rate.

Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2017-09-28T00:08:27Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) diana_carla_fernandes_oliveira.pdf: 1785085 bytes, checksum: d17d274bbea7e02f58960e76d1bbefd1 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2017-10-09T14:14:50Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) diana_carla_fernandes_oliveira.pdf: 1785085 bytes, checksum: d17d274bbea7e02f58960e76d1bbefd1 (MD5) / Made available in DSpace on 2017-10-09T14:14:50Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) diana_carla_fernandes_oliveira.pdf: 1785085 bytes, checksum: d17d274bbea7e02f58960e76d1bbefd1 (MD5) Previous issue date: 2016 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O Brasil ? um pa?s que se destaca pela produ??o de leite, ocupando a quinta posi??o mundial, segundo o Instituto Brasileiro de Geografia e Estat?stica (IBGE, 2015). O rebanho leiteiro brasileiro ? composto em sua maior parte por animais zebu?nos e mesti?os (cruzamento entre ra?as europeias e zebu?nas). Dentre as ra?as zebu?nas, o Gir e o Guzer? se destacam pela produ??o de carne ou leite, al?m de serem animais que se adaptam bem as condi??es do clima. Por muitos anos os programas de melhoramento gen?tico de gado de leite tinham como principal preocupa??o as caracter?sticas de produ??o. Todavia, o sucesso econ?mico da pecu?ria leiteira n?o est? associado apenas ? efici?ncia produtiva, mas tamb?m ? efici?ncia reprodutiva, sa?de e longevidade do rebanho. Contudo, os ganhos em produtividade levaram a redu??o na efici?ncia das caracter?sticas reprodutivas e ao decl?nio na longevidade. A longevidade ? uma caracter?stica altamente desej?vel em rebanhos leiteiros, em raz?o da sua rela??o com a lucratividade, pois em rebanhos com vacas mais longevas, tem-se uma redu??o com o custo de animais para reposi??o. Entretanto, a longevidade ? uma caracter?stica complexa influenciada por diversos fatores, como produ??o de leite, bem estar, endogamia e objetivos de cria??o. Al?m disso, a maioria das medidas de longevidade s?o obtidas tardiamente na vida da vaca ou at? mesmo ap?s a sua morte. Este fato, faz com que a sele??o direta para a longevidade seja impratic?vel devido ao tempo necess?rio para se obter a medida, bem como o longo intervalo de gera??es, sendo uma caracter?stica de baixa herdabilidade. Portanto, a sele??o indireta para longevidade tem sido utilizada por meio da sele??o de outras caracter?sticas de interesse econ?mico, expressas precocemente, como a idade ao primeiro parto, podendo contribuir para obten??o de ganhos gen?ticos. Sendo assim, o estudo das caracter?sticas de longevidade e as outras caracter?sticas de import?ncia econ?mica s?o indispens?veis para inclus?o da longevidade em programas de melhoramento gen?tico para produ??o de leite. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Zootecnia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2016. / Brazil is a country that stands out for milk production, ranking fifth in the world, according to the Brazilian Institute of Geography and Statistics (IBGE, 2015). The Brazilian dairy herd is mostly composed of zebu and mestizo animals (crossbreeding between European and zebu breeds). Among the zebu breeds, the Gir and Guzer? stand out for the production of meat or milk, besides being animals that adapt well the conditions of the climate. For many years the genetic improvement programs of dairy cattle had as main concern the production characteristics. However, the economic success of dairy farming is not only related to the productive efficiency, but also to the reproductive efficiency, health and longevity of the herd. However, gains in productivity led to a reduction in the efficiency of reproductive traits and a decline in longevity. Longevity is a highly desirable characteristic in dairy herds, because of its relation to profitability, since in livestock with longer cows, there is a reduction with the cost of replacement animals. However, longevity is a complex feature influenced by many factors, such as milk production, well-being, endogamy and creation goals. In addition, most longevity measures are obtained late in the life of the cow or even after death.This fact makes the direct selection for longevity impractical due to the time required to obtain the measure, as well as the long generation interval, being a characteristic of low heritability. Therefore, indirect selection for longevity has been used through the selection of other characteristics of economic interest, expressed early, such as age at first calving, and may contribute to obtain genetic gains. Thus, the study of longevity characteristics and other characteristics of economic importance are indispensable for inclusion of longevity in genetic breeding programs for milk production.

The objectives of this research were to evaluate breed differences for heat-stress resistance using age at first calving and first calving interval, and to assess breed by region interactions for seven regions of the United States for survival-related traits up to five years of age in Brown Swiss, Holstein, and Jersey cows. Age at first calving and first calving interval were studied in farms with two breeds, with Holstein and Brown Swiss or Holstein and Jersey cows. The survival-related traits were analyzed in farms with one or two breeds. Seven regions within the United States were defined: Northeast, Northwest, Central north, Central, Central south, Southwest and Southeast. The fertility traits were also analyzed in seven individual states: Wisconsin, Ohio, Oregon, California, Arizona, Florida, and Texas. Brown Swiss were older than Holsteins at first calving (833 ± 2.4 d vs. 806 ± 2.0 d in regions, and 830 ± 3.1 d vs. 803 ± 2.4 d in states), but Holsteins and Brown Swiss did not differ for first calving interval. Jerseys were younger than Holsteins at first calving and had shorter first calving intervals (P < 0.01). In data from individual states, Holsteins housed with Brown Swiss were older at first calving than Holsteins housed with Jerseys (800 ± 2.7 d vs. 780 ± 2.5 d). Holsteins housed with Jerseys had slightly shorter first calving intervals than Holsteins housed with Brown Swiss, and the interaction of "type of Holstein: with season of the first calving was highly significant (P < 0.01). Region and season effects were smaller for Jerseys than for Holsteins, thus, Jerseys showed evidence of heat-stress resistance with respect to Holsteins. Management modified age at first calving in Holsteins, depending on the type of herd they were located in. Longer calving intervals might have been partly due to voluntary waiting period to breed the cows. The survival-related traits were evaluated up to five years of age. They consisted of stayability, number of completed lactations, days lived, herd-life, and total days in milk. For herds with one breed, the order for stayability to five years of age, from longer to shorter-lived breed was: Brown Swiss, Jersey and Holstein, but for the ratio of days in milk to herd-life the order was: Holstein, Jersey and Brown Swiss, and for the ratio of days in milk to days lived, it was: Jersey, and Holstein and Brown Swiss tied. This last ordering was the same for number of lactations completed by five years of age. The results for two-breed herds were similar since Brown Swiss and Jerseys had larger (Chi-square P < 0.01) probabilities of living past five years of age than Holsteins, and for days in milk and number of lactations completed, Jerseys had higher values than Holsteins (P < 0.01), but Holsteins and Brown Swiss tied in some analyses. Breed by region interaction was always significant. If all other conditions were assumed equal, Jerseys would give fastest returns by five years of age. The overall conclusion is that Jerseys performed better for the traits analyzed, all of them highly influenced by environmental conditions. / Ph. D.

The aim of this diploma thesis was to evaluate the influence of live weight in the course in rearing heifers on milk yield Fleckvieh in economically squad Určice. 420 cows of Czech Fleckvieh breed in period of 5 years (2011-2016) were evaluated. Body weight of heifers was determined by bridging the transition from individual business records to the age of 3, 6, 12 and 15 month. The influence of bodyweight heifers during rearing on the usability and functional length were evaluated, as well as the effect of the age at first calving on milk yield and functional longevity. Last but not least were determined the most common causes of retirement of cattle from the herd. No significant effects of rearing of heifers on dairy milk yield or the longevity of cows were detected.

The aim of this study was to evaluate of selected factors on milking yeild and longevity of Czech Fleckvieh cattle. There were monitored the indicators of the amount of milk for the first lactation in kg, the lifetime performance in kg, the age at the first calving, the functional longevity in days, the lenght of the service period, the lenght of the meantime days, the live weight in kg, the elimination of the causes from the breed. 273 culled cows were included. The relationship between some of the observed factors were signifiant such as the amount of milk yeild on the first lactation and the lifetime performance. In the opposite, there was no signifiant relationship between the age at the first calving and the functional longevity. The milk performance at first calving has been increasing with the age.

The set includes 1782 heads of culling Czech fleckvieh cattle eliminated from 1 January 2012 to 1 September 2015. Influences on the first calving age, calving interval and lifetime milk yield were detected for data in the set. The following items were integrated among selected lifetime milk yield influences : genotype, herd, first calving age and first calving month. It was also tested whether the age of the first calving of milking cows is influenced by genotype and a herd. The last tested hypothesis was related to the influence of genotype and a herd on the length of the carving interval. The influence of genotype, lactation and the age of first calving cows on the way of elimination was investigated in the set as well. Multi-factor analysis of variance were used for the calculation of differences among the individual tested groups . With respect to statistical significance there was a statistically significant effect (p <0.05)of the herd and genotype on the age of the first calving cows found out. From the set it is evident that cows calved earlier reached better lifetime milk yield than cows calved at the older age (p <0.05). Another statistically significant difference (p <0.05) was found out within the first month of calving. Milking cows calved during colder periods of the year reached the higher lifetime milk yield. The influence of genotype on milk yield was not proved in this set. This also holds to reproductive parametres, there was no influence of genotype and the age of first calving on calving interval. When observing the outcome in terms of how we can positively evaluate the elimination of voluntarily culled milking cows, which is 34% .This situation is significantly lower than it is stated in literature and shows a good zootechnical care of the herds. In terms of elimination method there were the most dairy cows culled because of fertility - 31%. This fact shows that fertility is one of the main factors influencing the managament and profitability of dairy herds of cattle.

Orientador: Lucia Galvão de Albuquerque / Resumo: As características reprodutivas são fundamentais para a rentabilidade do sistema produtivo de gado de corte. Contudo, características como idade ao primeiro parto (IPP) e perímetro escrotal (PE) possuem desvantagens para serem utilizadas em programas de melhoramento genético tradicional, uma vez que são mensuradas em só um sexo e podem apresentar baixa herdabilidade. Nas últimas décadas os avanços nas tecnologias de análise de DNA têm permitido o desenvolvimento de procedimentos estatísticos como estudos de associação (GWAS) e seleção genômica (GS). Comumente têm-se utilizado marcadores de tipo SNP para desenvolver este tipo de estudos. Entretanto, outro tipo de marcador molecular os haplótipos, que são grupos de SNPs que estão em alto desequilíbrio de ligação (DL) podem ser utilizados neste tipo de estudo, uma vez que estes podem estar em maior desequilíbrio de ligação com os QTL quando comparados com os SNPs. O objetivo deste estudo foi verificar o uso de haplótipos em estudos de GWAS e GS, para características reprodutivas, em bovinos da raça Nelore. Para o estudo de GWAS, 2.390 observações de IPP e 4.832 informações para CE, provenientes de três programas de melhoramento da raça Nelore, foram utilizadas em um estudo de associação genômica ampla. 1900 fêmeas e 1500 machos jovens foram genotipados com o painel HD da Ilumina® (777K). 490 fêmeas e 3.332 machos jovens foram genotipados utilizando o painel da GeneSeek 75K. Os animais genotipados com painel de menor densidade fo... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The reproductive traits are fundamental for the profitability of the beef cattle production system profitability. However, traits such as age at firs calving (AFC) and scrotal circumference (SC) have disadvantages to be used in traditional breeding programs, since they are measured in only one sex and may have low heritability. In the last few decades, the advances in technology for DNA analysis allowed the development of statistical techniques as genomic-wide (GWAS) and genomic selection studies (GS). Commonly, SNPs markers have been used to perform these studies. Nonetheless, another molecular marker, the haplotype, that are SNPs in high linkage disequilibrium (LD), could be used in these studies, since these could be in higher LD with the QTLs when compared to the individual SNPs. The aim of this study was to verify the use of haplotypes in GWAS and GS, for reproductive traits, in Nelore cattle. In GWAS study, 2,390 and 4,832 animals with information of age at first calving (AFC) and scrotal circumference (SC) belonging to three Nelore breeding programs were used to perform the GWAS. The genotypes of 1900 heifers and 1500 young bulls were obtained with HD panel from Ilumina® (777K) and 490 heifers and 3332 young bulls were genotyped with the GeneSeek Genomic Profiler HDi 75K. Animals genotyped with lower density panel were imputed to HD using the FImpute program. Phenotype was adjusted for the contemporary groups fixed effects (Y*). Missing genotypes and linkage phase were... (Complete abstract click electronic access below) / Doutor

Orientador: Lucia Galvão de Albuquerque / Banca: Danísio Prado Munari / Banca: Márcio Cinachi Pereira / Resumo: Os objetivos deste estudo foram estimar associações genéticas entre o perímetro escrotal obtido aos 9 (PE9), 12 (PE12) e 18 meses de idade (PE18) e características reprodutivas medidas diretamente em novilhas tais como: idade ao primeiro parto (IPP), ocorrência de prenhez aos 16 meses de idade (Pr16) e reconcepção de fêmeas primíparas (REC), utilizando inferência Bayesiana, com intuito de verificar a possibilidade de incluí-las como critérios de seleção em programas de melhoramento genético de bovinos de corte. Foram analisados 158.148 dados de animais da raça Nelore, nascidos entre 1990 e 2006 e pertencentes ao arquivo zootécnico da Agropecuária Jacarezinho Ltda., localizada no município de Valparaíso, São Paulo. Foram realizadas análises uni e bi-características. Em análises bicaracterísticas, as estimativas de herdabilidade foram iguais a 0,22±0,05; 0,39±0,09; 0,20±0,06; 0,20±0,01; 0,54±0,03 e 0,17±0,03 para PE9, PE12, PE18, IPP, Pr16 e REC, respectivamente. As correlações genéticas estimadas entre PE9 e IPP, Pr16 e REC foram de -0,48±0,13; 0,51±0,13 e 0,02±0,19, respectivamente. As correlações genéticas entre PE12 e IPP, Pr16 e REC foram de -0,41±0,12; 0,35±0,12 e -0,16±0,17, respectivamente. As correlações genéticas entre PE18 e IPP, Pr16 e REC foram de - 0,29±0,13; 0,28±0,14 e -0,03±0,18, respectivamente. Esses resultados sugerem que a seleção de animais com maior perímetro escrotal, principalmente aos 12 meses de idade deverá ocasionar maior ocorrência de prenhez aos 16 meses e menor idade ao primeiro parto em fêmeas da raça Nelore / Abstract: The objectives of this study were estimate genetic associations between scrotal circumference obtained at 9 (SC9),12 (SC12) and 18 months of age (SC18) and reproductive traits measured directly in heifers as: age at first calving (AFC) occurrence of pregnancy at 16 months of age (HP16) and heifers subsequent rebreeding (HSR), using Bayesian inference, in order to verify the possibility of including them as criteria for selection in breeding programs for beef cattle. It were analyzed 158,148 records from Nelore cattle, born between 1990 and 2006 and belonging to Agropecuária Jacarezinho Ltda., located in Valparaíso council, São Paulo state. Single and two-trait analyses were accomplished. In two-trait analysis, the heritability estimates were equal to 0.22 ± 0.05, 0.39 ± 0.09, 0.20 ± 0.06, 0.20 ± 0.01, 0.54 ± 0.03, and 0.17 ± 0.03 for SC9, SC12, SC18, AFC, HP16 and HSR, respectively. The genetic correlation between AFC and SC9, HP16 and HSR were -0.48±0,13, 0.51±0,13 and 0.02±0,19, respectively. Genetic correlations between SC12 and AFC, HP16 and REC were -0.41±0,12, 0.35±0,12 and - 0.16±0,17, respectively. Genetic correlations between SC18 and AFC, HP16 and HSR were -0.29±0,13, 0.28±0,14 and -0.03±0,18, respectively. These results suggest that selection of animals with larger scrotal circumference, especially at 12 months of age should result in a higher incidence of pregnancy at 16 months and a decrease in age at first calving in Nellore females / Mestre

The aim of the work was to elaborate a literary review of the characteristics, reproductive properties of Holstein cattle and influences affecting the reproduction of cattle. Another objective of the work was to evaluate the selected influences on their reproduction in a group of selected dairy cows from the monitored cattle herd. The data were processed and sorted by genotype, level of milk performance, parity, length of dry period, length of insemination interval, difficulty of calving, age of the first calving and synchronization of estrous (Ovsynch). In evaluating the effect of the genotype on reproductive parameters, there were no statistically significant differences between purebred Holstein cows (H100) and crosses (H50-88C). In addition, the effect of milk yield on lactation on reproductive performance was evaluated. The results showed that with increasing performance, the values of reproduction indicators (insemination index, insemination interval and period service) have increased. The statistically lowest insemination index (1.70) and insemination interval (96 days) were detected in cows with a yield up to 8,000 kg. The service period (122 days) was conclusively the lowest in a cow group with a yield of 8,001 to 10,000 kg lactating milk. In contrast, the highest conclusive values of the insemination index, interval and period service were detected in a group of dairy cows with a yield above 12,001 kg of milk. It is further evident from the results that the values of the pregnancy rate after the first insemination increased with the increasing level of milk performance. The lowest value (27.14%) was detected in the group with the highest milk yield (over 12,001 kg of milk). There were no significant differences between the different groups of dairy cows in the evaluation of the influence of parity on the reproduction indicators. Furthermore, the influence of length of dry period was evaluated. The average dry period in the monitored herd was 69 days. The pregnancy rate after the first insemination was better for the group with a dry period over 61 days (40.38%). On the other hand, periods of service and days open values were lower in dairy cows with a dry period less than 60 days (119 and 394 days respectively). The length of uterine involution was also monitored by the length of insemination interval. Most cows in the monitored group of dairy cows (25.29%) were first inseminated 66th - 87th day after calving. No statistically significant differences were detected in the assessment of the age of the 1st calving and the severity of births on reproductive parameters. The use of controlled reproduction methods (Ovsynch) was also monitored and applied only in the case of reproductive disorders of dairy cows. In the monitored period, Ovsynch was used in only 10 dairy cows and the average service period was 140 days.