Thesis (MHSc--Health Science(Midwifery))--AUT University, 2009. / Includes bibliographical references. Also held in print (vi, 124 leaves ; 30 cm.) in the Archive at the City Campus (T 618.5 TRE)

Source: Masters Abstracts International, Volume: 47-01, page: 0319. Adviser: Dorothy K. Waller. Includes bibliographical references.

Research reported in this thesis was designed to quantify the impact of dystocia in heifers on beef cattle production in the Waggamba Shire of Southeast Queensland in the early 1990?s. The research was also designed to identify factors influencing the incidence of dytocia in beef heifers. It was found that the average beef cattle breeding property in the Waggamba Shire at the commencement of this study was 2090&plusmn;7.7 hectares and ran a total of 336&plusmn;1.6 breeders, of which 78&plusmn;1.1 were heifers. A large proportion (66%) of the breeders were either Hereford or Shorthorn. Seventy nine percent of properties had a 4&plusmn;0.24 month joining period falling between the months of September to March. All properties incorporated one or more of the subjective appraisal criteria of frame size, temperament, age and "soundness of type" when selecting heifers for joining. Nineteen percent of properties weighed heifers prior to joining to assess if critical mating weight had been attained. Forty percent of properties routinely had pregnancy diagnosis performed. The mean percent of calves weaned from the heifers that were pregnancy tested in calf was 81.9%. In the cow herd the mean percentage of calves weaned from pregnancy tested cows was 95.8%. The mean incidence of dystocia in heifers from surveyed properties was estimated to be 10% with a mean of 1.6% of heifers dying from dystocia each year. A mean of 13 working days was spent observing or assisting heifers each calving season. A benefit-cost analysis, incorporating a gross margin analysis and net present value calculations showed there was a $0.13 increase in the gross margin per hectare for each percentage decrease in the dystocia rate, representing an increase in the annual total gross margin of approximately $272 for each percent decrease in heifer dystocia for a 2090 hectare Waggamba Shire beef cattle property. Net present value calculations revealed that over a ten-year period, a property with five-percent dystocia in the heifers would have $34.81 per hectare extra income than a property with 40 % dystocia. This equated to $72440 extra income for an average sized Waggamba Shire property of 2090 hectares at the end of ten years. A significantly higher mean birth weight for calves requiring veterinary assistance for delivery compared to unassisted calves (p<0.01) was found. Examination of pelvic area data showed that assisted heifers delivering male calves had significantly larger mean pelvic areas and higher pelvic area:calf birth weight ratios than assisted heifers delivering female calves (p<0.01). It was found that male calves required a larger pelvic area for delivery compared to female calves, and also needed, on average, an extra 1.94 cm2 of pelvic area per kilogram of calf compared to the females. Results also showed that heifers requiring assistance had significantly higher body condition scores at calving (p<0.01). Heifers delivering male calves had a significantly higher mean body condition score than those delivering female calves (p<0.05). Results from analysing seasonal effects showed that calvings for which veterinary assistance was sought occurred significantly earlier in the calving season compared to unassisted calves (p<0.05). A retrospective study showed a positive correlation between yearling heifer body weight and yearling heifer pelvic area (p<0.01, r=0.29). This demonstrated a mean increase in yearling heifer pelvic area of 0.174 cm2 for each 1kg increase in body weight. The r2 value indicated that 8.9% of the variation in yearling heifer pelvic area was accounted for by changes in heifer body weight. The mean yearling pelvic area of heifers requiring assistance at calving was 182.2 &plusmn; 3.1cm2 compared to 193.5 &plusmn; 1.2 cm2 for heifers not requiring assistance. The difference of 11.3 cm2 was significantly different from zero (p<0.01). The mean Pelvic Area : Birth Weight ratios for assisted and unassisted calvings were 5.4 &plusmn; 0.01 cm2/kg and 6.6 &plusmn; 0.08 cm2/kg respectively and were significantly different (p<0.01). Calf birth weight was not significantly correlated with the heifers? yearling body weight. However, the type of delivery when calving as a two-year-old was significantly affected by the heifers? weight as a yearling (p<0.01). For the sub-population where yearling heifer body weight was measured, the mean yearling weight for the 63 heifers having calving difficulty as two-year-olds was 254&plusmn;5.3 kg, compared to 284.5&plusmn;2.95 kg for the 227 heifers not requiring assistance. The percentage of assisted calvings for the whole heifer population studied was 16.8%. For the sub-population where birth weight was measured, the mean calf birth weights for the 140 assisted and 655 unassisted calvings were 33.6&plusmn;0.36 kg and 31.0&plusmn;0.17 kg respectively and were significantly different (p<0.01). Analysis of variance revealed calf birth weight was significantly different (p<0.01) between males and females (32.2&plusmn;0.25 kg compared to 29.9&plusmn;0.21 kg respectively). Of the assisted calvings, 65% were male calves. The mean second trimester rainfall for assisted and unassisted calvings was 86.5&plusmn;6.0 mm and 110.4&plusmn;2.8 mm respectively. Chi-squared analysis showed an association between assisted birth numbers and rainfall category in the second trimester (X2 =13.4, p<0.01, df=1). There was also a significant association between assisted birth numbers and rainfall category in the third trimester (X2 = 11.9, p<0.01, df=1). The differences resulted from significantly more heifers requiring assistance when rainfall in the second trimester was less than the mean, and rainfall in the third trimester was greater than the mean. When all three trimesters were considered together, there was a significantly higher than expected number of assisted births for the High/Low/High and Low/Low/High groups of heifers (p<0.01), where High and Low refers to whether rainfall was above or below the mean during the trimester under investigation. Analysis of variance revealed significant differences in mean calf birth weight between the High and Low rainfall groups in the first and third trimesters. Mean birth weights of calves from the Low first trimester rainfall group were 1.6kg heavier than those from the High first trimester rainfall group (p<0.01), and mean birth weights of calves from the High third trimester rainfall group were 0.9kg heavier than those with low rainfall in the third trimester (p<0.02). When the analysis focused on the upper and lower rainfall quartiles, the significant difference between mean calf birth weights when grouped by High or Low rainfall in the first trimester was maintained. Mean calf birth weights from heifers exposed to lower quartile rainfall in the first trimester were 3.2kg heavier than the upper quartile group (p<0.01). This latter analysis failed to find a significant difference in mean calf birth weights between those exposed to different rainfall volume during the third trimester. In relation to month of calving, the mean calving dates for unassisted and assisted births of the 25th August and the 13th September respectively, were found to be significantly different (p<0.01). The mean calving date for the whole group was the 28th August. Two studies comparing heifers fed from approximately three months of gestation to achieve a mean condition score of < 3.5 at calving (Fat group), with those fed to achieve a condition score of < 3.0 at calving (Thin group) showed no significant difference in dystocia incidence between groups. Assessment of blood parameters suggested that heifers from the Fat group had increased levels of stress and tissue trauma associated with parturition compared to heifers from the Thin group. Specifically, heifers in the Fat group had significantly higher postpartum plasma CPK concentrations (p<0.05), significantly higher postpartum blood glucose concentrations (p<0.05), a trend towards higher postpartum plasma fibrinogen concentrations (p=0.09) and significantly lower plasma normalised calcium concentrations (p<0.01). Results revealed serum progesterone concentrations during gestation in the Thin group were significantly higher than in the Fat group at the May sampling time (p<0.05) of the First trial and trended that way in August for the Second trial (p=0.07). There was a trend for serum progesterone concentrations to be higher in the Fat group 24 hours postpartum (p=0.07), with the difference becoming significant at 48 hours postpartum (p<0.01). There were no differences in serum progesterone concentrations detected between the Fat and Thin groups at parturition. The presence of progesterone in subcutaneous fat was established, however there was no indication of it influencing serum progesterone concentrations during gestation or at calving. In the second trial, pelvic width was a mean of 0.6 cm wider in the Fat group compared to the Thin group at approximately two months prior to calving (p<0.05). No significant group or group by measuring time interactions were noted for pelvic height or pelvic area measurements. There was a trend for heifers in the Thin group to produce heavier calves than heifers in the Fat group (p=0.1). Two final studies were undertaken to investigate whether the seasonal and nutritional influences on heifer calving ability identified in the previous studies might be associated with dietary protein concentration of the heifers in the first two trimesters. Heifers were divided into High/High, High/Low, Low/High and Low/Low groups according to the dietary protein concentration they received in the first and second trimesters respectively. In both trials, mean calf birth weights and the numbers of heifers experiencing dystocia were not significantly different between groups. In the second trial, calves from the Low/Low and Low/High groups had significantly larger left and right cannon bone lengths (p<0.05). In the first trial the heifers in the High/High group had a greater mean pelvic height at the end of the first trimester (p<0.05), and in the second trial there was a trend heifers in the High/High group to have a greater mean pelvic height and pelvic area at the end of the second trimester (p=0.1 and 0.08 respectively). A significantly larger mean frame score occurred in the High/High group (p<0.05) of the second trial at the end of the second trimester. There was a trend for placental weights to be heavier for assisted calvings in both trials (p=0.07 and p=0.08 respectively). The correlation coefficient between placental weight and calf birth weight was significant (p<0.01, r=0.71) and demonstrated a mean increase in calf birth weight of 2.6 kilograms for each 1 kg increase in placental weight. The r2 value indicated that approximately 50% of the variation in calf birth weight was accounted for by changes in placental weight. In the second trial, heifers in the High/Low group had a significantly lower placental weight (p<0.05). When the data from the first trial was analysed based on delivery type, mean blood glutathione peroxidase activity was significant different, or had trends towards significance, between assisted and unassisted heifers throughout gestation except for one measurement at three months of gestation. Heifers requiring assisted deliveries had significantly higher GSH-Px activity at all of these times compared to unassisted contemporaries. Although this finding wasn't duplicated in the second trial, it was also not contradicted. In specifically addressing the aims of this study, it was concluded that the mean dystocia incidence in this district was approximately the same as that documented for beef heifers in previous studies. Dystocia caused significant economic loss to beef cattle production in this district. Factors identified by this study that were directly associated with increased dystocia incidence were: (a) Lower mean body weight of heifers at 12 months of age. (b) Lower mean pelvic area of heifers at 12 months of age. (c) Lower ratio of pelvic area of heifers at 12 months of age to calf birth weight. (d) Lower mean rainfall during the second trimester of gestation for heifers bred to calve as two-year-olds. (e) Higher mean body condition score at calving. (f) Higher mean calf birth weights. (g) Male calves. (h) A later mean calving date for heifers calving as two-year-olds. (i) Heavier placental weights at calving.

Dairy cows are increasingly predisposed to diseases in the periparturient time period due in part to immunosuppression. Dystocia amplifies the disease risk due to the increased tissue trauma and stress the animal endures during the lengthened parturition. To decrease the increased inflammatory response seen in dystocic animals and improve their well-being in the postpartum period, we administered either a potent steroid, dexamethasone (DEX), or a saline control (CON) to cows within 12 hours after a dystocic parturition. The inflammatory marker haptoglobin was measured as well as behavioral and production measures. We observed that primiparous DEX cows exhibited a greater haptoglobin concentration on d 3 and d 7 postpartum compared to primiparous CON cows. Behavior was seen to be altered between the treatments, with DEX cows having reduced locomotion and increased lying times in the week following parturition. These measures could indicate pain reduction, suggesting improved comfort. Milk yield was affected, with a reduction of 7.3 kg/d in multiparous DEX cows in comparison to CON cows for almost the entirety of the first month following dexamethasone treatment. No treatment effects were seen for milk production of primiparous cows. Additional research is needed for further investigation of the immunological and production effects of steroids on postpartum dairy cows, especially between parities. / Master of Science in Life Sciences / Dairy cows are most likely to develop metabolic diseases in the weeks leading up and following calving. This risk can be heightened in cows that experience a difficult calving process, most likely due to an increased inflammatory response. A potent steroid, dexamethasone, was assessed after a difficult calving to see if postpartum animal recovery is accelerated through dampening of the inflammatory response. Dairy cows were given either dexamethasone (DEX) or saline control (CON) within 12 hours after a difficult birth to counter the inflammatory response. Our study found that primiparous cows that received dexamethasone, exhibited a greater concentration of the inflammatory marker, haptoglobin, on d 3 and d 7 postpartum than in CON cows. This may be attributed to increased tissue trauma in first time calvings since there was no treatment difference in multiparous cows. Cows that received dexamethasone also had a reduction in locomotion and an increased amount of total lying time in the days following calving. Additionally, multiparous cows that received dexamethasone exhibited a reduction in milk production by 7.3 kg/d for almost the entirety of the first month following treatment. Future research needs to examine the long-term effects of dexamethasone on the mammary gland and the inflammatory response in different parity cows postpartum.

Submitted by GIANCARLO COSTI null (costi.giancarlo@gmail.com) on 2016-08-26T04:26:53Z No. of bitstreams: 1 Tese versão final submissão UNESP.pdf: 1498136 bytes, checksum: dce342a5294f8ed176c92af24709db8c (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-08-29T19:55:09Z (GMT) No. of bitstreams: 1 costi_g_dr_jabo.pdf: 1498136 bytes, checksum: dce342a5294f8ed176c92af24709db8c (MD5) / Made available in DSpace on 2016-08-29T19:55:09Z (GMT). No. of bitstreams: 1 costi_g_dr_jabo.pdf: 1498136 bytes, checksum: dce342a5294f8ed176c92af24709db8c (MD5) Previous issue date: 2016-07-27 / Os objetivos do presente estudo foram determinar as características de partos submetidos à intervenção manual e avaliar os efeitos dessa intervenção na taxa de remoção e no desempenho reprodutivo subsequente. Dados de 5.257 partos foram divididos em grupo Controle (n=1.433) e Intervenção (n=3.824). O critério para a intervenção manual nas fêmeas de ordem de parto 1 (OP1) foi determinado pela distocia, enquanto nas demais ordens de parto (OP), somente quando o intervalo entre o nascimento dos leitões foi maior que 10 minutos. Nas fêmeas de OP1, o percentual de partos submetidos à intervenção manual foi de 7,6%. Não houve diferença (P>0,05) na ocorrência de intervenções de acordo com as classes de tamanho de leitegada (<12, 12-15 e >15 leitões). A proporção de intervenção manual foi maior (P<0,05) no 2º trimestre e menor (P<0,05) no 4º trimestre. Não houve diferença (P>0,05) no 1º e 3º trimestres. A proporção de OP1 do grupo intervenção foi maior para partos com ao menos 1 natimorto (P<0,001), na taxa de natimortos (P<0,001) e na taxa de mumificados (P<0,05). Não houve diferença (P>0,05) para nascidos totais (NT) e nascidos vivos (NV). A taxa de remoção foi maior (P<0,001) para o grupo intervenção. A remoção não reprodutiva foi maior (P<0,05) para o grupo intervenção; enquanto a remoção reprodutiva, para o grupo controle (P<0,05). No desempenho reprodutivo subsequente, não houve diferença (P>0,05) entre os grupos para o intervalo desmame-estro (IDE), taxa de retorno ao estro (TRE), taxa de abortamento (TA), taxa de parto (TP), taxa de parto ajustada (TPA), NT, NV, natimortos (NM) e mumificados (MM). Nas fêmeas de ordem de parto maior que 1 (OP>1), a OP2 teve o menor percentual (P<0,001) de intervenção, enquanto a OP6-10, o maior (P<0,001). Não houve diferença (P>0,05) entre os grupos para as fêmeas OP3-5. Na classe de tamanho de leitegada, o grupo controle apresentou um maior percentual (P<0,05) de fêmeas na categoria <12 leitões, enquanto nas leitegadas >15 o grupo intervenção resultou em um maior percentual (P<0,05) de fêmeas. Não houve diferença (P>0,05) entre os grupos para a categoria 12-15 leitões. Quanto à classe período do ano, a proporção de fêmeas do grupo controle foi maior (P<0,001) no 1º trimestre e do grupo intervenção no 3º trimestre (P<0,001). Não houve diferença (P>0,05) no 2º e 4º trimestres. Nas fêmeas de OP>1, não houve diferença (P>0,05) entre os grupos no percentual de fêmeas com pelo menos 1 natimorto. As fêmeas com intervenção apresentaram maior média de OP (P<0,001), NT (P<0,05) e NV (P<0,05). Não foi observada diferença (P>0,05) para NM, MM, taxa de remoção, taxa de remoção reprodutiva e taxa de remoção não reprodutiva. Houve diferença (P<0,001) na OP média das fêmeas removidas. No desempenho reprodutivo subsequente das fêmeas de OP>1, não houve diferença (P>0,05) entre os grupos para as variáveis IDE, TRE, TA, TP, TPA, NT, NV e MM. Foi encontrada diferença apenas nos NM (P<0,05) e média de OP (P<0,001). / The aim of this study were to determine the characteristics of farrowing submitted to manual intervention and evaluate the effects of this intervention on the removal rate and the subsequent reproductive performance. Data from 5,257 farrowing were divided into control group (n=1,433) and intervention group (n=3,824). The criterion for manual intervention in sows on the parity order 1 (PO1) was determined by dystocia while in the other parity orders, (PO) when the interval between the birth of the piglets was higher than 10 minutes. In sows of PO1, the percentage of farrowing submitted to manual intervention was 7.6%. There was no difference (P>0.05) in the event of interventions according to litter size classes (<12, 12-15 and >15 piglets). The proportion of manual intervention was higher (P<0.05) in 2nd quarter and lower (P<0.05) in 4th quarter. There was no difference (P>0.05) on the 1st and 3rd quarters. The proportion of PO1 in the intervention group was higher for farrowing to at least one stillborn (P<0.001), stillborns rate (P<0.001) and mummified rate (P<0.05). There was no difference (P>0.05) for total born (TB) and born alive (BA). The removal rate was higher (P<0.001) for the intervention group. The non-reproductive removal rate was higher (P<0.05) in the intervention group while reproductive removal rate, for the control group (P<0.05). In the subsequent reproductive performance, there was no difference (P>0.05) between groups for weaning to estrus interval (WEI), return to estrus rate (RER), abortion rate (AR), farrowing rate (FR), adjusted farrowing rate (AFR), TB, BA, stillborns (SB) and mummified (MM). In PO sows greater than 1 (PO>1), PO2 had the lowest percentage (P<0.001) while the intervention PO6-10, the greatest (P<0.001). There was no difference (P>0.05) between groups for sows in the OP3-5. In litter size class, the control group had a higher percentage (P<0.05) of sows in the category <12 piglets while in litters >15 intervention group resulted in a higher percentage (P<0.05) of sows. There was no difference (P>0.05) between groups for the category 12-15 piglets. As the class, period of the year, the proportion of sows in the control group was higher (P<0.001) in the 1st quarter and the intervention group in 3rd quarter (P<0.001). There was no difference (P>0.05) on the 2nd and 4th quarters. In sows PO>1, there was no difference (P>0.05) between the groups in the percentage of sows with at least one stillborn. Sows with intervention had higher average of PO (P<0.001), TB (P<0.05) and BA (P<0.05). There was no difference (P>0.05) in SB, MM, removal rate, reproductive removal rate and non-reproductive removal rate. There were differences (P<0.001) in the PO average of removed females. In the subsequent reproductive performance of PO>1 sows, there was no difference (P>0.05) between groups for variables, WEI, RER, AR, FR, AFR, TB, BA and MM. A difference was found only in SB (P<0.05) and PO mean (P<0.001).

Orientador: Guilherme de Paula Nogueira / Coorientador: Luzia Helena Queiroz / Banca: Gisele Zoccal Mingoti / Banca: Rafael Silva Cipriano / Resumo: Os animais congênicos possuem apenas uma região específica do cromossomo transferida de uma linhagem para outra através de cruzamentos monitorados por análises genéticas. Essa metodologia foi utilizada para produzir linhagem congênica de bovinos da raça Nelore carreando o polimorfismo no gene da miostatina proveniente do Belgian Blue. O objetivo desse trabalho foi comparar o peso ao nascimento, incidência de partos distócicos e taxa de mortalidade neonatal em animais de 3 variações genéticas para o gene da miostatina (homozigotos sem o polimorfismo, heterozigotos e homozigotos mutados). Animais homozigotos sem a mutação nasceram com 31,19 kg ± 0,32 kg, os heterozigotos com 35,82 kg ± 0,32 kg (diferença de 4,63 kg) e os homozigotos mutados nasceram com 40,46 ± 0,32 kg, com acréscimo médio de 9,26 kg acima dos bezerros homozigotos não mutados (p=2 x 10-16). Além disso bezerros machos apresentaram um acréscimo de 1,55 Kg em relação as fêmeas. A taxa de distocia dos bezerros homozigotos sem o polimorfismo e dos heterozigotos foram de 5,4% e 5,7%. A taxa de mortalidade dos bezerros homozigotos sem o polimorfismo e dos heterozigotos foram de 5,4% e 5,2%, dentro das normalidades esperadas. Entretanto, animais homozigotos mutados apresentaram altas taxas de distocia 47,5% e de mortalidade de bezerros 37,3%. Os dados indicam que a mutação no gene da miostatina quando em heterozigose gera um aumento de peso ao nascimento sem causar aumento de distocia ou de mortalidade neonatal. Conclu... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Congenic animals have only one chromosome specific region transferred from one lineage to another through crosses monitored by genetic analysis. This methodology was used to produce a Nellore cattle congenic line carrying the myostatin gene polymorphism from Belgian Blue. The objective of this study was to compare birth weight, incidence of dystocy and neonatal mortality rate in animals from the 3 genetic variations for the myostatin gene (homozygotes without the polymorphism, heterozygotes and mutated homozygotes). Homozygous animals without the mutation were born with 31,19 ± 0,32 kg, heterozygotes werte born with 35,82 ± 0,32 kg, a difference of 4,63 kg and the mutated homozygotes were born with 40,46 ± 0,319 kg, with an increase of 9,26 kg above homozygotes without the polymorphism calves (p = 2*10-16). In addition, male calves showed an increase of 1,55 kg in relation to females. The rates of dystocia of calves homozygous within polymorphism and heterozygotes were 5,4% e 5,7%. The rates of mortality of calves homozygous within polymorphism and heterozygotes were 5,4% e 5,2%, within expected normalities. However, mutated homozygous animals had high rates of dystocia (47.5%) and calves mortality (37.3%). The data indicate that mutation in the myostatin gene when in heterozygosis results in an increase birth weight without causing increased dystocia or neonatal mortality. We conclude that animals heterozygotes can be produced on a large scale, and may be an advantageous str... (Complete abstract click electronic access below) / Mestre

Com o avanço de novas biotécnicas da reprodução (TE, FIV e Clonagem), exige-se o controle mais acurado da gestação e do parto, em razão dos problemas obstétricos decorrentes do nascimento de produtos com crescimento exacerbado ou com menor vitalidade por disfunções placentárias. Desta forma, a redução da mortalidade neonatal justifica-se por acompanhar o aprimoramento na área, visando ao bem-estar materno e neonatal, como também aos interesses do mercado pecuário. As distocias podem comprometer o fluxo sangüíneo materno-fetal e a ocitocina utilizada como agente ecbólico nas atonias uterinas pode aumentar o estresse do parto. Os objetivos deste estudo foram: identificar alterações do escore Apgar de vitalidade neonatal, temperatura corpórea, hemogasometria arterial, glicemia e cortisol ao nascimento e 1 hora pós-parto de neonatos nascidos em distintas condições obstétricas e verificar modificações da pressão arterial (PA), freqüência cardíaca, eletrocardiograma, glicemia e cortisol de vacas no pré-parto, intra-parto, pós-parto imediato e após 1 hora. Foram utilizadas 30 fêmeas bovinas e 30 bezerros da raça Holandesa subdivididos em: Grupo Eutocia (G EUT; n=10); Grupo Distocia com extração fetal forçada moderada a intensa (G DIST; n=10) e Grupo Atonia ou hipotonia uterina com infusão de Ocitocina (50UI) (G OCT; n=10). As vacas apresentaram hiperglicemia de estresse apenas 1 hora pós-parto no G EUT e G OCT, no entanto, já no intra-parto no G DIST. A distocia também elevou os níveis de cortisol no pós-parto imediato. Houve acréscimo significativo da PA no intra-parto do G DIST, decorrente de contrações uterinas e abdominais mais intensas. Os traçados eletrocardiográficos denotaram ritmo sinusal normal em todos os períodos. Os resultados demonstram adaptação hemodinâmica materna frente às alterações do parto, mesmo com infusão exógena de ocitocina. Os neonatos do G DIST ao nascimento apresentaram menor vitalidade (escore Apgar) e maior estresse (nível de cortisol) em relação aos demais grupos. Os bezerros apresentaram normotermia, a despeito da redução da temperatura corpórea 1 hora pós-parto, e mantiveram-se normoglicêmicos. Ainda, os valores de base-excess, HCO3- e pO2 eram baixos, enquanto os níveis de Anion-gap e pCO2, elevados. No entanto, apenas no G DIST observou-se acidose mista (metabólica e respiratória) evidente (pH<7,20), indicando maior grau de sofrimento fetal e redução do suprimento sangüíneo durante o parto. Os bezerros do G OCT apresentaram pCO2 superior e pO2 inferior aos demais grupos ao nascimento. A infusão de ocitocina pode promover padrões de contração uterina diferenciados, comprometendo ainda mais a oxigenação fetal. A ocitocina alterou momentaneamente as variáveis hemodinâmicas maternas com possível efeito bradicárdico e hipotensor intra-parto, promovendo menor adaptabilidade respiratória neonatal e, portanto, impondo assistência mais criteriosa ao nascimento. Todos os bezerros apresentaram reduzidos valores de hematócrito e hemoglobina, em decorrência da eritropoiese imatura e intensa metabolização de eritrócitos fetais. Após 60 minutos de vida, os bezerros apresentaram recuperação satisfatória do desequilíbrio ácido-base e capacidade evidente de termorregulação e manutenção glicêmica. A condição obstétrica ao nascimento é crítica para o desempenho clínico do neonato, comprometendo sua vitalidade inicial e influenciando a circulação materno-fetal nos casos de distocias. As alterações circulatórias maternas ocasionadas pela ocitocina são consideradas momentâneas, reversíveis e não comprometeram o êxito neonatal. / The novel reproductive biotechnologies (ET, IVF and Cloning) require more accurate control of pregnancy and parturition, due to obstetrical problems as a result of the large offspring syndrome or reduced calf vitality associated with placental anomalies. Hence, the reduction in neonatal mortality is justifiable as research in this area progresses, aiming maternal and neonatal well-being and livestock economic concernment. Dystocia may compromise dam-fetal blood flow and induces severe hypoxia at birth. Oxytocin employed as ecbolic treatment for uterine inertia can enhance calving stress. Therefore, the aims of this study were to identify abnormalities in neonatal Apgar score, body temperature, arterial blood gas analysis, glucose and cortisol assay at birth and after 1 hour of calving under distinct obstetrical conditions and to verify the changes on blood pressure (BP), heart rate, electrocardiogram record, glucose and cortisol assay of cows during the first stage of labor, intra-partum, immediately after calving and 1 hour later. Thirty Holstein cows and 30 Holstein calves were grouped according to the obstetrical condition into: Eutocia Group (EUT G; n=10); Dystocia Group with mild to severe obstetric assistance (DIST G; n=10) and Uterine Inertia Group treated with oxytocin (50UI) (OCT G; n=10). EUT G and OCT G cows showed stress-induced hyperglycemia 1 hour after calving. On the other hand, DIST G presented hyperglycemia yet during intra-partum. Dystocia also increased cortisol levels shortly after calving. During labor, DIST G presented significantly higher BP, due to uterine and abdominal strengthened contractions. Electrocardiogram recordings denoted normal sinus rhythm at all time points. DIST G neonates presented lower vitality (Apgar score) and higher stress (cortisol level) at birth compared to other groups. Calves were normothermic, despite the significative decrease in body temperature after 1 hour of birth, and remained normoglycemic. Moreover, base-excess, HCO3- and pO2 results were low, while Anion-gap and pCO2 were high, comparing to standard values. However, mixed acidosis (metabolic and respiratory; pH<7,2) was only noticeable in DIST G, suggesting higher fetal distress during calving and reduced blood supply (oxygenation). In addition, OCT G calves presented increased pCO2 and decreased pO2 at birth. Oxytocin infusion may cause a distinct pattern of uterine contraction, compromising neonatal hypoxia even more. The oxytocin infusion altered transitorily the maternal hemodynamic variables with a possible bradicardiac effect and intrapartum hypotension, causing lower neonatal respiratory adaptability, demanding more intensive care at birth. All newborns showed low hematocrit and hemoglobin concentration due to immature erythropoiesis and intense fetal erythrocyte metabolism. The present results indicate full maternal adaptation to labors requirement. Calves showed stark acid-base recovery during the critical period of adaptation to ex utero life, with also evident thermoregulation and glucose maintenance 1 hour after birth. The obstetrical condition presented at birth was determinant to neonatal clinical demeanor. Dystocia mainly compromised blood flow and oxygen supply and ultimately interfered with newborn vitality. Ponctual maternal circulatory alterations caused by oxytocin infusion were reversible and did not compromise neonatal outcome.

Com o avanço de novas biotécnicas da reprodução (TE, FIV e Clonagem), exige-se o controle mais acurado da gestação e do parto, em razão dos problemas obstétricos decorrentes do nascimento de produtos com crescimento exacerbado ou com menor vitalidade por disfunções placentárias. Desta forma, a redução da mortalidade neonatal justifica-se por acompanhar o aprimoramento na área, visando ao bem-estar materno e neonatal, como também aos interesses do mercado pecuário. As distocias podem comprometer o fluxo sangüíneo materno-fetal e a ocitocina utilizada como agente ecbólico nas atonias uterinas pode aumentar o estresse do parto. Os objetivos deste estudo foram: identificar alterações do escore Apgar de vitalidade neonatal, temperatura corpórea, hemogasometria arterial, glicemia e cortisol ao nascimento e 1 hora pós-parto de neonatos nascidos em distintas condições obstétricas e verificar modificações da pressão arterial (PA), freqüência cardíaca, eletrocardiograma, glicemia e cortisol de vacas no pré-parto, intra-parto, pós-parto imediato e após 1 hora. Foram utilizadas 30 fêmeas bovinas e 30 bezerros da raça Holandesa subdivididos em: Grupo Eutocia (G EUT; n=10); Grupo Distocia com extração fetal forçada moderada a intensa (G DIST; n=10) e Grupo Atonia ou hipotonia uterina com infusão de Ocitocina (50UI) (G OCT; n=10). As vacas apresentaram hiperglicemia de estresse apenas 1 hora pós-parto no G EUT e G OCT, no entanto, já no intra-parto no G DIST. A distocia também elevou os níveis de cortisol no pós-parto imediato. Houve acréscimo significativo da PA no intra-parto do G DIST, decorrente de contrações uterinas e abdominais mais intensas. Os traçados eletrocardiográficos denotaram ritmo sinusal normal em todos os períodos. Os resultados demonstram adaptação hemodinâmica materna frente às alterações do parto, mesmo com infusão exógena de ocitocina. Os neonatos do G DIST ao nascimento apresentaram menor vitalidade (escore Apgar) e maior estresse (nível de cortisol) em relação aos demais grupos. Os bezerros apresentaram normotermia, a despeito da redução da temperatura corpórea 1 hora pós-parto, e mantiveram-se normoglicêmicos. Ainda, os valores de base-excess, HCO3- e pO2 eram baixos, enquanto os níveis de Anion-gap e pCO2, elevados. No entanto, apenas no G DIST observou-se acidose mista (metabólica e respiratória) evidente (pH<7,20), indicando maior grau de sofrimento fetal e redução do suprimento sangüíneo durante o parto. Os bezerros do G OCT apresentaram pCO2 superior e pO2 inferior aos demais grupos ao nascimento. A infusão de ocitocina pode promover padrões de contração uterina diferenciados, comprometendo ainda mais a oxigenação fetal. A ocitocina alterou momentaneamente as variáveis hemodinâmicas maternas com possível efeito bradicárdico e hipotensor intra-parto, promovendo menor adaptabilidade respiratória neonatal e, portanto, impondo assistência mais criteriosa ao nascimento. Todos os bezerros apresentaram reduzidos valores de hematócrito e hemoglobina, em decorrência da eritropoiese imatura e intensa metabolização de eritrócitos fetais. Após 60 minutos de vida, os bezerros apresentaram recuperação satisfatória do desequilíbrio ácido-base e capacidade evidente de termorregulação e manutenção glicêmica. A condição obstétrica ao nascimento é crítica para o desempenho clínico do neonato, comprometendo sua vitalidade inicial e influenciando a circulação materno-fetal nos casos de distocias. As alterações circulatórias maternas ocasionadas pela ocitocina são consideradas momentâneas, reversíveis e não comprometeram o êxito neonatal. / The novel reproductive biotechnologies (ET, IVF and Cloning) require more accurate control of pregnancy and parturition, due to obstetrical problems as a result of the large offspring syndrome or reduced calf vitality associated with placental anomalies. Hence, the reduction in neonatal mortality is justifiable as research in this area progresses, aiming maternal and neonatal well-being and livestock economic concernment. Dystocia may compromise dam-fetal blood flow and induces severe hypoxia at birth. Oxytocin employed as ecbolic treatment for uterine inertia can enhance calving stress. Therefore, the aims of this study were to identify abnormalities in neonatal Apgar score, body temperature, arterial blood gas analysis, glucose and cortisol assay at birth and after 1 hour of calving under distinct obstetrical conditions and to verify the changes on blood pressure (BP), heart rate, electrocardiogram record, glucose and cortisol assay of cows during the first stage of labor, intra-partum, immediately after calving and 1 hour later. Thirty Holstein cows and 30 Holstein calves were grouped according to the obstetrical condition into: Eutocia Group (EUT G; n=10); Dystocia Group with mild to severe obstetric assistance (DIST G; n=10) and Uterine Inertia Group treated with oxytocin (50UI) (OCT G; n=10). EUT G and OCT G cows showed stress-induced hyperglycemia 1 hour after calving. On the other hand, DIST G presented hyperglycemia yet during intra-partum. Dystocia also increased cortisol levels shortly after calving. During labor, DIST G presented significantly higher BP, due to uterine and abdominal strengthened contractions. Electrocardiogram recordings denoted normal sinus rhythm at all time points. DIST G neonates presented lower vitality (Apgar score) and higher stress (cortisol level) at birth compared to other groups. Calves were normothermic, despite the significative decrease in body temperature after 1 hour of birth, and remained normoglycemic. Moreover, base-excess, HCO3- and pO2 results were low, while Anion-gap and pCO2 were high, comparing to standard values. However, mixed acidosis (metabolic and respiratory; pH<7,2) was only noticeable in DIST G, suggesting higher fetal distress during calving and reduced blood supply (oxygenation). In addition, OCT G calves presented increased pCO2 and decreased pO2 at birth. Oxytocin infusion may cause a distinct pattern of uterine contraction, compromising neonatal hypoxia even more. The oxytocin infusion altered transitorily the maternal hemodynamic variables with a possible bradicardiac effect and intrapartum hypotension, causing lower neonatal respiratory adaptability, demanding more intensive care at birth. All newborns showed low hematocrit and hemoglobin concentration due to immature erythropoiesis and intense fetal erythrocyte metabolism. The present results indicate full maternal adaptation to labors requirement. Calves showed stark acid-base recovery during the critical period of adaptation to ex utero life, with also evident thermoregulation and glucose maintenance 1 hour after birth. The obstetrical condition presented at birth was determinant to neonatal clinical demeanor. Dystocia mainly compromised blood flow and oxygen supply and ultimately interfered with newborn vitality. Ponctual maternal circulatory alterations caused by oxytocin infusion were reversible and did not compromise neonatal outcome.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2009. / Härtill 4 uppsatser.

Yearly calvings are essential to the sustainability of modern dairy farming. Currently, calving difficulty (or dystocia) affects one in six calvings among UK dairy herds but vary from 2 to 50% internationally. In dairy cows, despite reports of impaired performance, the extent and threshold of the effect of dystocia on health and performance remains unclear. Over the past years, there has also been increasing concerns about the levels of pain experienced by the dystocial cows. Better understanding of their parturition progress and behaviours is needed so that informed decisions on pain mitigation can be taken. Additionally, the impact of dystocia (besides stillbirth) should also be addressed in dairy calves. The objective of this study was to address the effects of a difficult calving on the health and welfare of both dairy cows and calves. Retrospective analyses of an experimental farm’s detailed records were used to relate calving difficulty with health and performance of the dairy cow. The results showed that after any difficulty at calving, dairy producers incur long-lasting shortfalls in milk sales. Dystocial cows also have impaired fertility, are more likely to leave the herd early and have a higher risk of dystocia at the following calving, thus there is a long-term detrimental impact on dystocial cows. Video monitoring of calvings allowed detailed investigation of the parturition progress and behaviours of dystocial Holstein cows giving birth to singleton liveborn calves. The study of calving behaviours and parturition progress indicated longer later stages of parturition, increased restlessness and tail raising in the six hours preceding expulsion of the calf, for dystocial cows receiving farm assistance compared with cows calving unaided. This may relate to the expression of higher levels of pain when dystocia occurs. The onset of maternal behaviour was not delayed following calving difficulty, and firm conclusions could not be drawn from investigation of some behavioural indicators of pain in the first three hours postpartum. Experimental work allowed the monitoring of a cohort of 496 calves born with various degrees of birth difficulty over two years. All but one vet assisted calves were born dead, and farmer assisted calves were more likely to be stillborn than calves born without assistance. Stillborn dystocial calves displayed larger internal damage, than stillborn eutocial calves, but they did not have a different body shape at birth than dystocial calves that survived. Dystocial dairy calves that survived the birth process had lower vigour at birth, had higher salivary cortisol, acquired lower passive immunity and received more health treatments in the neonatal period. Dystocial heifers also had higher mortality rates by weaning but had similar growth to first service. Historical records from the farm also showed that dystocial heifer calves were three times more likely to have died by weaning and by first service than calves born without assistance. For those who survived, there was, however, no indication of altered growth to weaning or subsequent impaired fertility. This may be explained by the early mortality of the most badly affected calves or by farm management. However, their high mortality rates still raise welfare concerns. Altogether, results suggest that dairy calves born with any difficulty have poorer welfare in the neonatal period and possibly beyond. The experience of any calving difficulty in dairy cattle therefore not only impairs the welfare of the cow, but also the welfare from their resulting calf. Any strategy implemented to lower the occurrence and mitigate the effects of dystocia will therefore improve the welfare of the cows, their calves and enhance the farm’s economic sustainability.