M.S.

Two studies were conducted to determine if 7-d MGA or PRID treatment initiated on d 17 of the estrous cycle altered: 1) follicular development, 2) estradiol-17β (E2) and progesterone (P4) concentrations, and 3) patterns of release of luteinizing hormone (LH). In both studies, Angus, Angus x Holstein or Holstein cows 2 to 6 yr of age were randomly assigned to receive either MGA (.5 mg⋅hd⁻¹⋅d⁻¹; n = 23) or PRID (n = 26) for 7 d or to serve as untreated controls (n = 14). Real time, B-mode ultrasound, equipped with a 7.5 mHz linear-array transrectal transducer, was used to conduct daily ovarian scans beginning 3 (Study 1) or 9 d (Study 2) after onset of estrus. Jugular venous blood samples (45 ml) were collected coincident with ovarian scans. In study 2, cows were fitted with indwelling jugular catheters 17 (Control, MGA and PRID), 20 and 23 d (MGA and PRID) after onset of estrus and blood samples were collected at 15-min intervals for 6 h for determination of LH. Interestrus interval was extended (P<.05) for 3 to 5 d in MGA-treated cows exhibiting two or three dominant follicles (classified as MGA-2 and MGA-3, respectively) or PRID-treated cows compared to controls exhibiting two or three dominant follicles during the estrous cycle (control-2 and control-3, respectively). Forty-four percent of MGA-treated cows ovulated the dominant follicle present at the beginning of MGA treatment. In both studies, days from detection of the ovulatory follicle until ovulation were greater (P<.01) in MGA-2 and control-2 cows than control-3, MGA-3 and PRID cows. Diameter of the ovulatory follicle was greater (P<.01) 9 d before estrus and growth rate of the ovulatory follicle was less (P<.02) in MGA-2 and control- 2 cows than control-3, MGA-3 and PRID cows. Serum P4 decreased 3 d earlier (P<.02) during the estrous cycle of MGA-2 and control-2 cows than control-3, MGA-3 and PRID cows. Serum E2 was greater (P<.01) 7 d before estrus in MGA-2 cows than all other treatment groups. Changes in mean and baseline LH concentrations and amplitude of LH pulses on d 17, 20 and 23 after onset of estrus did not differ (P>.10) among treatments. Luteinizing hormone pulse frequency was greater (P<.03) on d-20 after onset of estrus in MGA-2 cows than MGA-3 and PRID cows (4.3 ± .6 vs 2.6 ± .3 and 3.2 ± .4, respectively). In addition, LH pulse frequency did not differ (P>.10) 17 or 23 d after onset of estrus among treatments. In conclusion, MGA treatment extended the dominance phase of development of ovulatory follicles, which resulted in the premature increase in serum E2 and frequency of LH release, whereas the dominant follicle present at the beginning of PRID treatment underwent atresia and another preovulatory follicle developed. / Ph. D.

Anatomical features of bovine cervical epithelium were investigated with respect to mucus secretion and sperm transport. Techniques included: 1. Surface staining of fixed tissue blocks in Harris' hematoxylin followed by steriomicroscopic examination, 2. Model construction from serial sections using both computer-aided and plexiglas assembly of epithelial tracings, 3. Histochemical investigation using five follicular phase animals (four bred naturally 8 to 12-h before slaughter) and three luteal phase animals. Cross-sections of two samples from each quarter cervix were stained with (1) Alcian blue (AB) at pH 1.0 (sulfomucins) and at pH 2.5 (sialomucins and sulfomucins); (2) periodic acid Schiff (PAS) (neutral mucins) and AB (pH 2.5); (4) high iron diamine (HID) (neutral and sulfomucins) with AB (pH 2.5). Additional samples were processed for ultrastructural examination. The mucosa was characterized by longitudinal primary and secondary folds which maintained continuity throughout the cervix, with numerous tertiary shallow ’grooves’ apparent on all epithelial surfaces. No evidence was found suggesting blind-ending glands or crypts. Staining results in follicular animals indicated a predominance of neutral and sulfated mucins in apical areas with secreted mucins extending as sheets from these areas toward the central canal. In basal areas (within grooves) sialomucin production was predominant with secreted mucins evident within grooves and between neutral mucin layers. In luteal phase animals, sulfated and neutral mucins were abundant in both basal and apical areas, while sialomucin production was decreased. Using light and transmission electron microscopy, spermatozoa observed within the cervix appeared unidirectionally opposed to ciliary beat. Suggested privileged paths for the transport of viable spermatozoa are within grooves, where sialomucins were most predominant. / Master of Science / incomplete_metadata

Thirty-three Holstein cows were superovulated with follicle stimulating hormone. Embryos were non-surgically recovered 6 days post-mating. Ninety embryos were morphologically evaluated and placed in culture in Hams F-10 media supplemented with a 10% protein source (steer serum, bovine serum albumin, or uterine flushings). Embryo development was observed every 12 h. Treatment differences were evaluated by assigning a numerical value of Oto 4 to each embryo representing the most advanced stage of development reached in vitro (O=no development, 4= hatched blastocyst). Data were then analyzed by analysis of variance, and Chi-square contingency analysis. Development of embryos was comparable in steer serum and bovine serum albumin but differed significantly from heat-treated or non heat-treated uterine flushings. Since albumin alone was able to support embryo growth it suggests that the albumin component of steer serum may be responsible for the development observed with that treatment. However, the possibility of non-albumin compounds contributing to the success of this protein source cannot be ruled out. Uterine fluids were unable to promote growth of embryos in vitro. Several explanations can be offered. The uterine fluids utilized were collected from ovariectomized hormonally induced cows and may not reflect the naturally occurring proteins of the normal uterus. The proteins may reflect a uterine stage which does not coincide with the age of the embryos. The level at which the uterine proteins were supplemented may have exceeded normal levels in the uterus and may have become inhibitory and lastly, the uterine fluids may have contained an abnormal amount of immunoglobulins which could interfere with normal embryo development. Analysis of the mean time to reach each stage demonstrated the similarity in the time course of development between the embryos supplemented with steer serum or bovine serum albumin in culture and embryos in vivo. This suggests that culture conditions other than uterine flushing supplementation were very favorable to embryo development. / M.S.

Two studies were conducted to investigate the role of the bovine cervix in filtering abnormal sperm. ln Study 1, semen containing high levels of abnormal sperm was vaginally deposited in 12 cows 80 hours after prostaglandin F₂α treatment. At slaughter, 4-, 8- or 12 hours post-insemination, sperm were flushed from the excised uteri with fixative. Pooled across times post-insemination, viability was greater for uterine vs inseminate sperm, based upon vital smears prepared from inseminate and uterine flush samples. Uterine levels of normal sperm, determined by differential interference contrast (DIC) microscopy, were greater than were inseminated. In Study 2, heifers were estrus synchronized in pairs using prostaglandin F₂α, then inseminated with semen containing high levels of abnormal sperm. In each pair, semen of high viability (Experiment 1, n=10) or low viability (Experiment 2, n=6) was deposited vaginally in one heifer and within the uterine corpus of the other. Using DIC microscopy, viability and morphology were coincidentally determined for sperm in samples from the fixed inseminate and the retrograde mucus, vaginal mucus, cervix, uterus and in vitro incubation of inseminate recovered and fixed 12 hours post-insemination. Uterine sperm quality did not differ between insemination sites, except lower uterine levels of live abnormal sperm alter intrauterine vs vaginal insemination of low viability semen probably due to disproportionately low viability of one abnormality. Sperm viability was enhanced and morphology unchanged in the uterus vs low viability inseminate, while sperm viability was unchanged and abnormal sperm subtly reduced in uterus vs high viability inseminate. Greater levels of live and live normal sperm were found deeper between cervical folds than at apical aspects of folds. Vaginal mucus sperm viability was lower compared to other tract locations and inseminate, especially after high viability insemination. Compared to inseminate viability, retrograde mucus sperm viability was high after vaginal insemination and low alter intrauterine insemination. Differential death of abnormal vs normal sperm neither with incubation of insemination in vitro nor, presumably, in vivo. Results show little evidence of cervical filtration based upon sperm morphology. Sperm retention in the female tract was predominantly related to sperm viability with only very subtle morphology effects. / Ph. D.

Call number: LD2668 .T4 1984 P72 / Master of Science

Dissertation (PhD(Agric))--University of Stellenbosch, 2007. / ENGLISH ABSTRACT: This study is a search for a quantifiable measure which estimates the genetic merit of female animals’ breeding efficiency. For practical reasons, such a measure must be both simple and inexpensive to record, irrespective of the herd management strategy. A literature investigation was undertaken to summarize breeding objectives for reproduction efficiency and to review different ways of expressing genetic reproduction efficiency. Traits to assess these in terms of the breeding objective, merits and requirements in terms of data collection are discussed. During the lifetime of a cow events occur which influence her fertility. A distinction is made between component traits and aggregate traits: a component trait points to one event, while aggregate traits are composites of more than one event. Although all the traits discussed seem relevant for breeding value estimation, the practical application depends on the herd management system in use. Age at first calving and days to calving are component traits that are easily and inexpensively measurable. Heritability estimates for the age at first calving were moderate. The heritability estimated for days to calving was 0.09. Calving rate comes close to the overall breeding objective. The estimated heritability of calving rate is low (0.04), resulting in slow genetic improvement. Calving success was defined and investigated even though some constraints exist. A sire model proved that genetic variation exists for calving success on the underlying scale. The corresponding heritability estimate was 0.27. Three categorical traits were defined. For stayability a sire variance of 0.41 was estimated with a heritabitity on the underlying scale of 0.27. The sire variances and heritabilities estimated for retention and calf tempo were high. Of the three traits, calf tempo is the one that reflects the true fertility of the bull’s female progeny. Calf tempo was redefined as net breeding merit, a trait describing the retention of male animals and the reproductive performance of their female offspring. The obtained sire variances show that the trait is heritable and can be improved by selection. Net breeding merit gives an indication of the ‘success’ of sires in a given population. A heritability estimate of 0.20 was estimated on a data set comprising offspring of bulls older than nine years, but when offspring of all sires were included, heritability estimates of 0.08 and 0.11 for the Afrikaner and Bonsmara, respectively, were found. Adjusting for young females was investigated by using the best linear unbiased estimate (BLUE) deviations to derive adjustment factors for herd level in order to predict performance for net breeding merit. Variation in the BLUE deviations occurred between all age class groups for the Afrikaner, whereas for the Bonsmara the variation between the BLUE deviations for the 3 year olds seems greater than the variation in the other age groups. It is suggested that the standardized curve for herd performance level derived from the BLUE deviations be used to adjust the phenotypic values of younger animals. This way the comparison between older and younger animals should be more valid. In conclusion, reproductive traits are heritable and genetic improvement can be achieved through selection. Any economical viable beef enterprise should include at least one trait in their selection criteria that will improve the reproductive efficiency. / AFRIKAANSE OPSOMMING: Hierdie studie is ‘n ondersoek na ‘n kwantifiseerbare maatstaf wat die genetiese meriete van vroulike diere se teeldoeltreffendheid beraam. Om praktiese redes moet so ‘n beraming sowel eenvoudig as goedkoop wees om te bepaal, onafhanklik van die kudde bestuurstrategie. ‘n Literatuurstudie is onderneem om die teeldoeleindes vir reproduktiewe doeltreffendheid op te som, sowel as om die verskillende wyses van genetiese reproduksiedoeltreffendheid beskrywing onder oë te neem. Verskeie eienskappe om hierdie beskrywings in terme van teeldoeleindes, meriete en dataversamelings-vereistes te raam, word bespreek. Gedurende ‘n koei se leeftyd kom gebeurtenisse voor wat haar vrugbaarheid beïnvloed. Daar word onderskei tussen komponenteienskappe en aggregaateienskappe: ‘n komponenteienskap verwys na een gebeurtenis, terwyl aggregaateienskappe na samestellings van meer as een gebeurtenis verwys. Hoewel al die eienskappe wat bespreek word relevant voorkom, sal die praktiese toepassing afhang van die kuddebestuurstelsel in gebruik. Ouderdom by eerste kalwing en dae tot kalwing is komponenteienskappe wat maklik en goedkoop bepaal kan word. Oorerflikheidsramings vir die ouderdom van eerste kalwing was matig. Die oorerflikheidsraming vir dae tot kalwing was 0.09. Kalffrekwensie is baie na aan die oorkoepelende teeldoelwit. Die geraamde oorerflikheid vir kalffrekwensie is laag (0.04), wat stadige genetiese verbetering tot gevolg het. Kalfsukses is gedefinieer en ondersoek, hoewel enkele beperkings bestaan het. ‘n Vaar-model het aangetoon dat genetiese variasie ten opsigte van kalfsukses op die onderliggende skaal bestaan. Die ooreenkomstige oorerflikheidsraming was 0.27. Drie kategoriese eienskappe is gedefinieer. Vir blyvermoë in die kudde is ‘n vaar-variansie van 0.41 geraam, met ‘n oorerflikheid van 0.27 op die onderliggende skaal. Die vaar-variansies en oorerflikhede wat vir retensie en kalftempo bereken is, was hoog. Van die drie eienskappe is kalftempo die een wat die ware vrugbaarheid van die bul se vroulike nageslag reflekteer. Kalftempo is herdefinieer as netto teelmeriete, ‘n eienskap wat die retensie van manlike diere en die reproduktiewe prestasie van hulle vroulike nasate beskryf. Die verkreë vaar-variasies wys dat die eienskap oorerflik is en verbeter kan word met seleksie. Netto teelmeriete gee ‘n aanduiding van die “sukses” van ‘n vaar in ‘n gegewe populasie. ‘n Oorerflikheidsraming van 0.30 is verkry op ‘n datastel bestaande uit die nageslag van bulle ouer as nege jaar, maar as die nageslag van alle vaars ingesluit is, was die oorerflikheidsraming onderskeidelik 0.08 en 0.11 vir die Afrikaner en Bonsmara. Aanpassing vir jong vroulike diere is ondersoek deur gebruik te maak van die beste lineêre onpartydige beramings (BLUE) om korreksiefaktore vir die kuddevlak te verkry, ten einde die prestasie ten opsigte van netto teelmeriete te voorspel. Variasies in die BLUE afwykings het voorgekom tussen alle ouderdomsgroepe vir die Afrikaner, terwyl vir die Bonsmara die variasie tussen BLUE afwykings vir die 3-jaar oud diere groter was as vir die ander ouderdomsgroepe. Dit word voorgestel dat die gestandardiseerde kurwe vir kuddeprestasievlak wat afgelei word van BLUE afwykings gebruik word om die fenotipiesewaardes van jonger diere aan te pas. Op hierdie wyse behoort die vergelyking tussen ouer en jonger diere meer geldig te wees. Ten slotte, reproduktiewe eienskappe is oorerfbaar en genetiese vordering is moontlik deur seleksie. Enige ekonomies lewensvatbare vleisbees-onderneming behoort ten minste een eienskap wat die reproduktiewe doeltreffendhied sal verbeter, in te sluit in seleksie kriteria.

Orientador: Fabíola de Paula Lopes / Banca: Gisele Ziccal Mingoti / Banca: José Antônio Visintin / Banca: Marcelo Fábio Gouveia Nogueira / Banca: Fernanda da Cruz Landim / Resumo: Divergências genéticas de termotolerância foram demonstradas entre animais Bos taurus taurus (Holandesa) e Bos taurus indicus (Nelore). O efeito deletério do estresse térmico sobre o potencial de desenvolvimento do oócito é maior para Bos taurus taurus em comparação aos oócitos Bos taurus indicus. Portanto, o presente estudo determinou o perfil do transcriptoma em oócitos das raças Nelore e Holandesa submetidos ao estresse térmico durante a maturação in vitro (MIV), bem como a abundância de RNAm de genes candidatos em oócitos e células do cumulus submetidos aos mesmos tratamentos. Vacas não lactantes das raças Holandesa e Nelore foram submetidas à aspiração folicular guiada por ultra-som durante a estação fria. Os complexos cumulus-oócitos (CCOs) foram aleatoriamente distribuídos nos tratamentos controle (38,5 °C por 22 horas) e estresse térmico (41 °C por 12 horas, seguido de 38,5 °C por 10 horas) durante a MIV. Oócitos desnudados foram submetidos à análise de microarray bovino (Affymetrix). Genes com fold change de pelo menos 1,5 e P<0,05 foram considerados diferencialmente expressos. A análise de microarray demonstrou 127, 9 e 6 genes diferencialmente expressos entre Raça, Temperatura e interação Raça x Temperatura, respectivamente. Os genes diferencialmente expressos foram avaliados por RT-PCR em oócitos e nas suas respectivas células de cumulus. Houve uma correlação positiva entre o fold change do microarray e do RT-PCR dos oócitos para os genes KIF3A, CLDN11, BIRC3, DAP, MT1E, CCT4, DICER1 e DENND3. Em particular, o gene membro da família cinesina 3A (KIF3A) foi induzido em oócitos de Holandesa, enquanto que os genes da proteína associada à morte (DAP) e de tráfego intracelular de membrana domínio DENN/MADD 3 (DENND3) foram reprimidos em oócitos de Holandesa quando comparados a Nelore. A abundância relativa do RNAm da molécula antioxidante metalotioneína 1E ... / Abstract: Genetic divergences in thermotolerance have been demonstrated between Bos taurus taurus (Holstein) and Bos taurus indicus (Nelore) animals. The deleterious effect of heat stress on oocyte developmental potential is greater for Bos taurus taurus as compared to Bos taurus indicus oocytes. Therefore, the present study determined transcriptome profile in Nelore and Holstein oocytes subjected heat shock during in vitro maturation (IVM) as well as mRNA abundance of selected candidate genes in Nelore and Holstein heat-shocked oocytes and cumulus cells. Non-lactating Holstein and Nelore cows were subjected to ultrasound-guided follicle aspiration during the cool season. Cumulus-oocyte complexes (COCs) were randomly assigned to control (38.5°C for 22 hours) and heat shock (41°C for 12 hours followed by 38.5°C for 10 hours) treatments during IVM. Denuded oocytes were subjected to Affymetrix bovine microarray. Genes with fold change of at least 1.5 and P< 0.05 were considered differently expressed. Microarray analyses demonstrated 127, 9 and 6 genes differentially expressed between Breed, Temperature and Breed x Temperature interaction, respectively. Selected differentially expressed genes were evaluated by RTPCR in oocytes and respective cumulus cells. There was a positive correlation between oocyte microarray and RT-PCR fold change for the genes KIF3A, CLDN11, BIRC3, DAP, MT1E, CCT4, DICER1 and DENND3. In particular, the member of the kinesin family 3A (KIF3A) gene was up-regulated in Holstein oocytes, while the deathassociated protein (DAP) and the protein trafficking gene DENN/MADD domain containing 3 (DENND3) were down-regulated in Holstein oocytes as compared to Nelore. The mRNA relative abundance of the antioxidant molecule metallothionein 1E (MT1E) was higher in Holstein cumulus cells, whereas, claudin 11 (CLDN11) that participates in cellular tight junctions, was higher in Nelore. Moreover, heat shock down regulated MT1E mRNA abundance ... / Doutor

This thesis provides an overview of the literature on reproduction attributes of the Holstein Friesian cattle and its influence on the cattle reproductive indices. One of the goals was to evaluate the influence of selected factors on the reproduction indices for a pre-selected group of dairy cattles. The data has been processed and sorted by the lactation production levels, daily production, order of lactation and the age of the first calving. The data about the used bulls has been processed as well. Another goal of the thesis was acquisition of the data about excluded cows. For the excluded cows, the age, order of lactation, reason for exclusion and life-long production have been recorded. The data for the thesis have been obtained from the production control records and database of breeds in the selected Holstein cattle breeding. The dairy cattles, which got in calf during the years 2017 and 2018 have been evaluated. In particular, for 2017 and 2018, the evaluation was carried out on 190 and 229 dairy cattles respectively, which makes the total of 419 evaluated cows. For those dairy cows, the insemination index data, insemination interval, gestation after first insemination, service period and gestation period has been recovered from the zootechnical register. The evaluation of excluded dairy cows contained 339 dairy cows, which have been excluded during years 2017 and 2018. For the evaluation of the used bulls, the total count and description of how the bull for insemination have been selected is provided. Evaluation the influence of level of lactation production on the reproduction indices has shown a significant (p0,05) statistical relation between production levels and duration of the service period. It has also been proven that this has an influence on the insemination index levels. The lowest values (p0,05) of service period and insemination index have been detected for dairy cattles with production up to 6 999 kg. On the other hand, the highest values of service period and insemination index have been recorded for the dairy cattles with production up to 9 000 kg (p0,05). The influence of daily dairy production levels on the reproduction indices have been evaluated as well. It can be clearly seen from the results that as the daily dairy production increases, the service period increases as well. The lowest values (p0,05) of the service period was recorded for breeds, who had the daily production levels up to 24.99 kg. Opposed to that, the highest values of service period have been recorded for dairy cattles with average daily milk production over 30 kg. The evaluation of order of lactation on the reproduction indices did not show any significant statistical results (p0,05). Furthermore, during the evaluation of first calving, no statistically significant differences have been shown (p0,05). Last reproduction index we have evaluated was gestation after the first insemination. The groups were divided by the production levels, daily milk production, order of lactation and age of the first calving. For each group, the percentage of cattles that got in calf after first insemination has been computed. On average, this value was 36.28%.

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.