Three experiments were conducted for this dissertation with the goals to; 1) determine conjugated linoleic acid (CLA) effects on net-energy balance (EBAL) and milk production parameters during periods of nutrient/energy stress, and 2) investigate temporal CLA effects on mammary lipogenic gene expression. Study one was designed to determine if abomasal CLA infusion could reduce milk fat synthesis and partition nutrients towards alternative milk components in feed restricted rotationally grazed dairy cows. Data indicate abomasally-infusing CLA reduced milk fat synthesis in nutrient restricted grazing dairy cows and improved calculated EBAL and milk protein production. Another period of transitory stress experienced by the lactating dairy cow is immediately postpartum and study two objectives were to feed rumen inert-CLA to evoke milk fat depression (MFD) and investigate production and bioenergetic parameters. Data indicated a high CLA dose (3 x greater than needed in established lactation) inhibited milk fat synthesis immediately postpartum and improved calculated EBAL in grazing dairy cows. A curvilinear relationship existed between the severity of CLA-induced MFD and milk yield response. Moderate CLA-induced MFD (<~35%) tended to increase milk yield whereas severe MFD (>~35%) diminished this response. Previous research speculated that extensive MFD might decrease Δ⁹-desaturase (stearoyl CoA desaturase; SCD) and subsequent membrane fluidity to such an extent as to adversely affect cellular functions and inhibit milk secretion, thus decreasing milk yield. However, SCD inhibition was temporally independent in the present study, offering little support for the aforementioned theory. Mammary sensitivity to CLA increased as lactation progressed and previous speculations attributed this to reduced contribution of de novo synthesised fatty acids or increased competition from circulating non-esterified fatty acids immediately postpartum. However, data indicate that de novo fatty acids and milk fat trans-10, cis-12 CLA content don’t appreciably change during early lactation, (even though MFD became more severe) offering little support for either hypothesis. Study three investigated the effects of intravenous CLA infusion on temporal expression of mammary lipogenic genes to determine if trans-10, cis-12 CLA down regulates expression of a key gene (i.e. acetyl CoA carboxylase, ACC, the rate limiting enzyme in de novo fatty acid synthesis) and reduction in other mammary lipid synthesis genes is due to lack of substrate (i.e. malonyl CoA), or an alternative indirect mechanism. Data indicated however, that mammary lipogenic genes (ACC, fatty acid synthetase and SCD) followed a similar temporal pattern, providing more support for a global regulator (i.e. sterol regulatory element binding protein-1, peroxisome proliferator-activated receptor-γ or nuclear factor- κB) rather than a specific key enzyme effect.

Die Mastitis beim Milchrind hat eine große ökonomische Bedeutung, daher liegt derzeit ein Forschungsschwerpunkt auf der Aktivierung und Stabilisierung der körpereigenen Abwehr zur Bekämpfung von Euterentzündungen. Besonders im peripartalen Zeitraum liegt eine Prädisposition für Infektionen vor, da eine physiologische Abwehrschwäche besteht. Daher erscheint die Förderung der Bildung von Antikörpern durch Impfungen sinnvoll. Getestet wurde der Einfluss von bestandsspezifischen E. coli-Vakzinen auf das Immunsystem, das Erregervorkommen in der Milch und die Eutergesundheit. Differenziert wurden Impfstoffe, die einerseits aus den Originalkulturen der antigenen Erreger (sogenannte large colony variants, LCV) oder aber aus den kleineren, intrazellulär persistierenden Erregern (small colony variants, SCV) hergestellt wurden. Letztlich zeigte sich bei Anwendung der Vakzinen an Milchrindern kein Unterschied zwischen LCV und SCV, bei beiden Impfstoffen war eine vakzinationsbedingte deutliche Steigerung der Antikörpertiter, welche einen Einfluss auf Erregervorkommen und Eutergesundheit hatte, erkennbar.

The objective of this study was to determine the ability of a passive temperature monitoring system consisting of radio frequency identification (RFID) boluses with thermistors and receiver panels to detect ovulation in high performing dairy cows. The twice-daily reticulo-rumen temperature (Trr) acquisitions of 41 early-lactation Holstein dairy cows were analyzed. The data were analyzed using two criteria: six baseline days (2d, 3d, 4d, 5d, 6d, 7d) and four temperature deviations (0.2°C, 0.3°C, 0.4°C, 0.5°C). The best criteria were chosen by selecting the baseline/deviation combination that gave the best positive predictive value (PPV). The system detected 93 true positive and 267 false positive alerts of ovulation, with a monitoring rate (MR) of 47% and a PPV of 46.2%. There were indications that the Cow Temperature Monitoring System could have a future as an ovulation detection aid, but due to the unreliability of the Wi-Fi transmission of acquisitions, more research needs to be conducted before definite conclusions can be drawn.

This thesis is an investigation of the prevalence of, and factors associated with, hock, knee, and neck injuries on dairy cattle in Canada. Tie-stall (n = 100) and free-stall farms (n = 90) were visited in Quebec, Ontario, and Alberta, Canada. Cows were scored for hock (tarsus), knee (carpus), and neck injuries on a 3 or 4-point scale combining the attributes of hair loss, broken skin, and swelling. Animal-based and environmental measures were taken which were hypothesized to be risk factors for injury. On tie-stall farms the mean herd-level prevalence of hock, knee, and neck injuries was 56, 43, and 30%, respectively. On free-stall farms the mean herd-level prevalence of hock, knee, and neck injuries was 47, 24, and 9%, respectively. Having sand stall bases, feed rail heights above 140 cm and managing cows to reduce slips and falls were associated with reduced injury prevalence. / Dairy Research Cluster (Dairy Farmers of Canada, Agriculture and Agri-Food Canada, Canadian Dairy Commission)

The objective of this thesis was to determine the effects of frequency of milking and feed delivery on the behavioural patterns and productivity of lactating dairy cows. In two independent experiments, twelve free-stall housed, lactating Holstein dairy cows were exposed to either varying milking frequency or varying feed delivery frequency over 21-d periods. In the first study, cows milked three times per day and multiparous cows produced more milk than those milked twice per day and primiparous cows. Milking three times per day altered the distribution of feeding activity throughout the day. Multiparous cows had longer, and larger meals, while primiparous cows had smaller, more frequent meals throughout the day when milked three times per day. In the second study, cows delivered feed three times per day consumed more DM than those fed once per day and twice per day. Feed delivery frequency had little effect on feeding behaviour and the distribution of feeding activity, but altered the magnitude of DMI following feed delivery. Cows delivered feed more frequently achieve greater daily DMI by consuming more feed following the return from milking and the delivery of feed. / This project was financially supported by a Dairy Farmers of Ontario (Mississauga, Ontario, Canada) research grant and an Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA; Guelph, Ontario, Canada)/University of Guelph Production Systems research grant. Additional project support was received from the Canadian Foundation for Innovation (CFI; Ottawa, Ontario, Canada) and the Ontario Research Fund (Toronto, Ontario, Canada).

This thesis investigates the relationship between cow lying behavior and udder health in free-stall housed dairy cows milked 3x/d. Two longitudinal studies were undertaken; in the first, associations with risk of elevated somatic cell count (eSCC) were determined and, in the second, associations between management practices, post-milking standing duration (PMSD), and risk of intramammary infection (IMI) were determined. A PMSD of >90 min was associated with reduced odds of eSCC. A PMSD of 90 to 120 min was associated with reduced odds of CNS IMI, as was provision of feed around time of milking. Providing ample feed bunk space, having lower free-stall stocking densities, and providing feed around the time of milking promoted PMSD. Overall, these results suggest that management practices which promote PMSD may help to improve udder health in free-stall cows milked 3x/d.

The aim of this bachelor´s thesis was to capture the basic behaviour categories in dairy cattle breeding cows in production stable in relation to their reproductive cycle. The research was carried out on four groups: after calving (12 pcs), between 1st - 3rd insemination (50 pcs), heavily pregnant (39 pcs) and cows in the dry period (32 pcs). The milk and combined utility type of dairy cows were housed in a large scale stable. Milk yield was monitored as a factor of milk performance traits. Milk yield of Holstein cattle (H) and Czech Fleckvieh cattle (C) were 35.10 kg and 30.88 kg (P>0.05) during increasing milk flow. In a group of dairy cows in insemination period Holstein and Czech Fleckvieh cows produced 31.16 kg of milk respectively 25.15 kg. The differences in milk yield were statistically significant (P0.01). In the group of heavily pregnant cows decreased milk yield in both Holstein and Czech Fleckvieh cattle to 18.18 kg respectively 17.31 kg of milk (P>0.05). The length of insemination interval (from the group of fertility traits) reached 75.57 days within group of dairy cows H and 67.82 days within group C. Service period of dairy cows H was 151.99 days and 152.25 days within dairy cows C (P>0.05). The length of feed intake was determined while differences in behaviour were being assessed between groups. In the group after calving took the feed intake 25.7 % days, in the group of dairy cows in insemination period 23.9 %, by heavily pregnant cows 25.8 % and by dairy cows standing in the dry period 29.6 % of total time. The length of standing achieved by the group after calving was 18.8 %, by the group of dairy cows in the insemination period 24.0 %, by heavily pregnant dairy cows 16.5 % and by dry cows 15.7 % of total time. The length of rest was by the group after calving 42.0 %, by the group of dairy cows in the insemination period 37.1 %, by heavily pregnant dairy cows 53.9 %, and by dry cows 53.2 % of total time. The average aggression in the group after calving reached a value 3.67 per one cow. In the group of dairy cows in the mating period increased aggressiveness on 4.68. In the group of heavily pregnant dairy cows fell the average to 0.33 and nearly the same was in the group of dry cows (0.38). The incidence of comfort behaviour in a group of cows after calving was for one cow 11.08. In the group of inseminated cows decreased significantly to 3.78. Other decrease was observed within the group of heavily pregnant dairy cows and by the group of dry cows too (1.44 or 1.28 per one dairy cow).

The objectives of the current experiment were to characterize patterns of daily rumination time, activity and milk production around the diagnosis of health disorders, and to determine if the addition of rumination and activity data to a commercial dairy farm fresh cow health monitoring program improves sick cow detection and diagnosis of disease during the first 30 DIM. Holstein animals (primiparous = 282, parous = 328) were enrolled in the experiment approximately 60 d before expected calving date, and were divided into two groups (Collar Monitoring-CM-, n=293 ; Control-C-, n=317). Electronic rumination and activity monitoring tags (SCR Engineers Ltd., Netanya, Israel) were fitted on cows neck at enrollment and were kept until approximately 80 &#177; 3 DIM. Farm personnel checked the cows and performed the diagnosis of disease following the routine of the dairy. Cows from both of the groups were sent to check based on the parameters used by the farm. Additionally, cows from group CM were checked based on the data provided by the tags. Serum calcium concentration was determined using blood samples collected from 0 to 4 DIM. BHBA concentration was determined twice using blood samples collected from 4 to 12 DIM and 7 to 20 DIM. Subclinical hypocalcemia (SCHC) and subclinical ketosis (SCK) were characterized as Ca &lt;8.55 ng/dL, and BHBA &gt;1,000 &micro;mol/L in any blood sample, respectively. Daily rumination time (DRT), daily activity (ACT), and daily milk production patterns for cows with clinical disease showed differences with healthy cows around diagnosis (P $lt;0.05). Cows with subclinical disorders and calving problems had changes in DRT, ACT, and milk production patterns compared to healthy cows around calving (P &lt;0.05). DRT and ACT patterns of regrouped cows were characterized by differences with non-regrouped cows around regrouping (P &lt;0.05). No differences were found for DRT, ACT, and milk production between groups C and CM. The overall sensitivity (Se) of collars to identify health disorders was 56.4% (n = 402 cases), considering a positive outcome as at least 1 alert based on rumination and activity from -7 to +2 d relative to diagnosis. Se was higher for cows with more than one disorder (75.8%) than for cows with one disease only (45.5%) (P &lt;0.001). No differences between groups were found for overall Se, and Se for cows with one disease. However, for cows with more than one disorder, Se was higher in group CM than C (P = 0.005). Overall specificity, positive predicted values, and negative predicted values were 74.5%, 46.4%, and 57.6%, respectively. The overall incidence of disease was 48%. No differences between groups were found for overall incidence of disease and each disease. Among primiparous, group CM (43.3%) had higher overall incidence of disease than group C (32.1%) (P = 0.05). Although were not differences for parous, incidence of metritis tended to be greater in group C than CM (P = 0.1). Incidence of SCK and SCHC was not different between groups. A higher percentage of animals from group CM than C received treatment (P = 0.04), and these differences were seen in primiparous (P = 0.03), but not in parous. However, a higher percentage of parous not diagnosed as sick from group CM received support treatments (drenching and fluids) compared to C. No differences were shown for culling rate, service rate until 150 DIM, conception rate at first service, and percentage of cows marked as do not breed between groups. DRT and ACT patterns for sick cows showed differences around diagnosis compared to healthy cows. The use of DRT and ACT data was able to identify sick cows in a commercial dairy farm. Results suggest that it may be also useful to identify cows needing attention before clinical signs are visible, improving the prevention of health disorders. Its usefulness may vary according to parity, disease, severity of disease and health compromise, and the intensity of the farm system for checking cows. Future research should evaluate different parameters and parameters thresholds based on rumination and activity data for identifying sick cows, and their efficiency in dairies with different degrees of intensity for checking animals health. / Os objetivos deste experimento foram caracterizar os padrões diários do tempo de ruminação, atividade, e produção de leite arredor do diagnostico de doenças, e determinar se a adição de dados de ruminação e atividade num programa de monitoramento de saúde de vacas de uma fazenda comercial melhora a detecção de vacas doentes e o diagnostico de doenças durante os primeiros 30 DEL. Animais Holstein (primíparas = 282, multíparas = 328) foram utilizados no experimento aproximadamente 60&#177;3 dias antes da data esperada de parto, e foram divididos em dois grupos (Collar Monitoring-CM-, n=293; Control-C-, n=317). Dispositivos eletrônicos para o monitoramento da ruminação e atividade acoplados a colares (SCR Engineers Ltd., Netanya, Israel) foram colocados nas vacas no enrolamento e mantidos ate aproximadamente 80&#177;3 DEL. O monitoramento de saúde das vacas e o diagnostico de doenças foram realizados pelos funcionários da fazenda seguindo a rotina do estabelecimento. Os animais dos dois grupos foram enviados para checagem de saúde baseados nos parâmetros utilizados pela fazenda. Adicionalmente, as vacas do grupo CM foram checadas baseadas na informação suprida pelos colares. A concentração de cálcio sérico foi determinada usando uma amostra de sangue coletada do dia 0 ao 4 em leite. A concentração de beta-hidroxibutirato (BHBA) foi determinada duas vezes usando amostras de sangue coletadas do dia 4 ao 12, e do 7 ao 20 do posparto. Hipocalcemia subclínica (SCHC) e cetose subclínica (SCK) foram caracterizadas como Ca &lt;8.55 ng/dL, e BHBA &gt;1000 &micro;mol/L em qualquer amostra, respectivamente. Os padrões diários do tempo de ruminação (DRT), atividade (ACT), e produção de leite de vacas com doenças clinicas arredor do diagnostico mostraram diferencias comparados com vacas sadias (P &lt;0.05). Vacas com alterações subclínicas e problemas de parto tiveram alterações nos padrões de DRT, ACT, e produção de leite arredor do parto, quando comparadas a vacas controle (P &lt;0.05). Padrões de DRT e ACT de vacas reagrupadas se caracterizaram por diferencias com vacas não reagrupadas (P &lt;0.05). Não foram achadas diferencias em DRT, ACT, e produção de leite entre os grupos C e CM. A sensibilidade (Se) dos colares para identificar problemas de saúde foi de 56.4% (n = 402 casos), considerando como evento positivo a ocorrência de pelo menos uma alerta baseada em ruminação e atividade dentro dos 7 dias prévios ate 2 dias apos o diagnostico de doença. A Se foi maior para vacas com mais de uma doença (75.8%) que em para vacas com uma doença somente (45.5%) (P &lt;0.001). Não se acharam diferencias na Se geral, nem Se para vacas com uma doença somente entre grupos. Porem, a Se foi maior no grupo CM que no grupo C (P = 0.005) em vacas com mais de uma doença. A especificidade (Sp), valores da predição positiva (PPV), e valores da predição negativa (NPV) foram 74.5%, 46.4%, e 57.6%, respectivamente. A incidência de doença foi de 48%. Não houve diferencias entre grupos na incidência de doença, nem na incidência de cada doença. Entre as primíparas, o grupo CM (43.3%) teve maior incidência de doença do que o grupo C (32.1%) (P = 0.05). Embora não teve diferencia na incidência de doença entre grupos para multíparas, a incidência de metrite teve uma tendência a ser maior no grupo C do que no grupo CM (P = 0.1). A incidência de SCK e SCHC não foi diferente entre grupos. Maior percentagem de animais do grupo CM recebeu tratamento do que do grupo C (P = 0.04), e estas diferencias foram observadas em primíparas (P = 0.03), mas não em multíparas. Contudo, uma maior percentagem de animais não diagnosticados como doentes do grupo CM recebeu tratamentos de suporte, quando comparado ao grupo C. Não se acharam diferencias na taxa de descarte, taxa de serviço aos 150 DEL, taxa de concepção ao primeiro serviço, e percentagem de vacas de descarte reprodutivo entre grupos. Resumindo, os padrões de DRT e ACT de vacas doentes arredor do diagnostico de doença mostraram diferencias comparados com os de vacas sadias. O uso da informação de DRT e ACT foi capaz de identificar vacas doentes numa fazenda comercial. Os resultados sugerem que a utilização dos colares pode ser util para identificar vacas com necessidade de atenção antes da aparição de sinais clínicos visíveis, melhorando a prevenção de problemas de saúde. A utilidade da utilização do sistema pode variar de acordo a ordem de partos dos animais, doença em questão, severidade da doença e comprometimento de saúde do animal, e com a intensidade do sistema de monitoramento de saúde dos animais da fazenda. Próximas pesquisas deveriam avaliar diferentes parâmetros baseados na informação de ruminação e atividade para identificar vacas doentes, e a sua eficiência em fazendas com diferentes graus de intensidade para o monitoramento de saúde.

The objectives of this study were to characterize the hematological and productive pattern during the peripartum in cows with and without anemia, as well as to evaluate the erythrogram in animals that presented metritis puerperal acute (MPA), lameness, acetonemia, increased non-esterified fatty acids (NEFA) and cows with different categorization of body condition score (BCS). In study 1, 50 Holstein cows (29 multiparous and 21 primiparous) were used. Blood samples and physical examination were performed at 13 different times: 18 &#177; 3, 12 &#177; 2, 5 &#177; 1, and 2 &#177; 1 before calving, and 7, 14, 21, 30, 45 and 60 days postpartum. Erythrogram evaluations were performed, and red blood cell count (RBC), hemoglobin concentration, packed cell volum (PCV), and absolute hematimetric values of mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), mean corpuscular hemoglobin, RDW, serum concentrations of iron, betahydroxybutyrate (BHBA), AGNE and total bilirubin (TBIL) were determined for the biochemical analyzes. Anemia was classified according to hemoglobin values &lt;7 g / dL and globular volume &lt;24%. The prevalence of anemia was higher in the period 60 days postpartum affecting 18.3% of the animals, the pattern of anemia presented was normocytic, normochromic, regenerative. RBC, PCV and hemoglobin were lower (P &lt;0.05) for animals with anemia. While the animals with MPA and lameness the value of the erythrogram was very similar throughout the postpartum period. No difference was observed between the groups according to the values of NEFA, BCS and loss of BCS during the periods performed in the postpartum period. In conclusion the anemic animals presented the values of the physical examination according to the physiological limits, the anemia did not cause productive losses in the affected animals. It was not evidenced that animals with MPA and claudicants presented a greater reduction of blood crass, excluding the occurrence of inflammatory anemia, and although the prevalence of anemia increased during postpartum, it was not possible to characterize the main cause of the reduction of hematological values between the categorizations. In the second study, blood was sampled from 336 animals (252 multiparous and 84 primiparous) between 21 and 30 days in lactation (DEL) on 7 farms in the State of São Paulo with the objective of characterizing the prevalence of anemia in dairy cows, prevalence of anemia in different categorizations such as: lactation number, BCS at the time of collection, dystocia, retention of fetal membranes, mastitis, digestive problem, lameness and acetonemia, , as well as the analysis erythrogram, biochemical profile, BCS, and milk production among animals with and without anemia. In conclusion, the prevalence of anemia was low (16.3%) and no association with the categorizations performed in this study, it was not possible to characterize the cause of anemia through biochemical analysis. / Os objetivos deste estudo foi caracterizar o padrão hematológico e produtivo durante o periparto em vacas com e sem anemia, assim como avaliar o eritrograma em animais que apresentaram metrite puerperal aguda (MPA), claudicação, acetonemia, valores de ácidos graxos não esterificados aumentados (AGNE) e vacas com diferentes categorizações de escore de condição corporal (ECC). No estudo 1, foram utilizadas 50 vacas Holandesas (29 multíparas e 21 primíparas), foram realizadas colheitas sanguíneas e exame físicos em 13 momentos diferentes: 18 &#177; 3, 12 &#177; 2, 5 &#177; 1, e 2 &#177; 1 antes do parto, parto, e 7, 14, 21, 30, 45 e 60 dias após o parto. Foram realizadas avaliações do eritrograma sendo mensurado a contagem de hemácias (RBC), concentração de hemoglobina, volume globular, além dos valores hematimétricos absolutos do volume corpuscular médio (VCM), concentração hemoglobínica corpuscular média (CHCM), hemoglobina corpuscular média (HCM) e RDW, para as análises bioquímicas foram determinadas a concentração sérica de ferro, betahidróxidobutirato (BHBA), AGNE e bilirrubina total (TBIL). Anemia foi classificada de acordo com os valores de hemoglobina &lt; 7 g/dL e o volume globular &lt; 24 %. A prevalência de anemia foi maior no período 60 dias após o parto afetando 18.3% dos animais, o padrão da anemia apresentado foi normocítica, normocrômica, regenerativa. Os valores das contagens de hemácias, volume globular e hemoglobina foram menores (P &lt; 0.05) para os animais com anemia. Enquanto os animais com MPA e com claudicação, o valor do eritrograma foi muito semelhante ao longo do pós-parto. Não foi observado diferença entre os grupos de acordo com os valores de AGNE, ECC e perda de ECC durante as coletas realizadas no pós-parto. Em conclusão os animais anêmicos apresentaram os valores do exame físico de acordo com os limites fisiológicos, a anemia não provocou perdas produtivas nos animais afetados. Não foi evidenciado que animais com MPA e claudicantes apresentassem maior redução da crase sanguínea, excluindo a ocorrência de anemia inflamatória, sendo que embora a prevalência de anemia aumentasse durante o pós-parto não foi possível caracterizar a causa principal da redução dos valores hematológicos entre as categorizações realizadas. No estudo 2, foram realizadas coletas sanguíneas em 336 animais (252 multíparas e 84 primíparas) entre 21 e 30 dias em lactação (DEL) em 7 fazendas no Estado de São Paulo com objetivo de caracterizar a prevalência de anemia nos animais, prevalência de anemia em diferentes categorizações realizadas como: distocia, retenção dos anexos fetais, mastite, problema digestivo, claudicação, acetonemia, ECC no momento da coleta e número de parto, assim como a análise do eritrograma, bioquímico e ECC e produção de leite entre os animais com e sem anemia. Em conclusão a prevalência de anemia foi baixa prevalência (16.3 %) e nenhuma associação com as categorizações realizadas nesse estudo, adicionalmente não foi possível caracterizar por meio de análises bioquímicas a causa da anemia.

Digital dermatitis is a top cause of lameness in dairy cattle that results in ulcerative lesions on the feet. Topical salicylic acid has been shown to provide similar efficacy to the antibiotic drugs used previously, but there is no milk withholding time established in the United States. The objective of this study was to provide data in order to establish this withholding period. A secondary objective was to evaluate outcomes among treatments. Treatment groups were topical applications of the following drugs: salicylic acid paste, salicylic acid powder, and tetracycline. The lesions were scored at day 0, day 7, and day 28 post-treatment. Milk samples were collected the day before treatment, 4 hours, 8 hours, 24 hours, 36 hours, and 48 hours post-treatment. Results indicated that most cows did not show detectable levels of salicylic acid after 24 hours.