The effect of a varied duration of the close up period of primiparous cows on the incidence of dystocia and perinatal calf mortality

Deckblatt-Impressum persönlicher Dank Inhaltsverzeichnis Abkürzungsverzeichnis Einleitung Literaturübersicht Material und Methoden Ergebnisse der prospektiven Stichprobe Diskussion Schlussfolgerungen Zusammenfassung Summary Literaturverzeichnis Danksagung SelbständigkeitserklärungIn den letzten Jahren sind die perinatalen Kälberverluste insbesondere bei den Abkalbungen von primiparen Kühen stark angestiegen. Hauptursache dafür sind Schwergeburten. Auf ihr Auftreten hat das Geburtsgewicht des Kalbes den größten Einfluss. In dieser Studie wurde untersucht, welchen Einfluss die Dauer der antepartalen Transitfütterung auf die körperliche Entwicklung des primiparen Muttertieres, auf dessen Abkalbeverhalten und hormonelle Geburtsvorbereitung sowie auf die Ausprägung von dessen labordiagnostischen Parametern hat. Daneben wurden die Auswirkungen der variierten Vorbereitungsdauer auf das Geburtsgewicht, die Körpermaße, die perinatale Vitalität sowie die perinatalen klinischen und labordiagnostischen Parameter des Kalbes untersucht. Die Datenerhebung fand zwischen November 2003 und Oktober 2004 in einem brandenburgischen Milchviehbetrieb statt. 433 primipare, schwarzbunte, künstlich besamte Färsen wurden zufällig auf drei Gruppen verteilt. Gruppe 1 wurde eine Woche (0-11 Tage), Gruppe 2 zwei Wochen (12 16 Tage) und Gruppe 3 drei Wochen (17 49 Tage) vorbereitet. Die Futterration enthielt in der Trockenmasse 6,1 6,6 MJ NEL /kg, 12,1 15,0 % Rohprotein, 18,6 23,0 % Rohfaser und einen Stärke- und Zuckergehalt von 16,5 22,7 %. Bei den Färsen wurde ab der sechsten antepartalen Woche wöchentlich die Rückenfettdicke mittels Ultraschall gemessen und Blut aus der Schwanzvene entnommen. Letzteres wurde auf Östradiol-17ß und Progesteron untersucht. Eine direkt nach der Abkalbung entnommene Blutprobe, wurde zudem auf diverse Stoffwechselparameter untersucht. Der beobachtete Geburtsverlauf wurde in drei Schwierigkeitsgrade eingeteilt. Grad 0 entspricht einer problemlosen Geburt, Grad 1 einer Geburt mit leichter Geburtshilfe und Grad 2 einem schweren Geburtsverlauf mit dem Einsatz des mechanischen Geburtshelfers. Vor der ersten Kolostrumaufnahme wurde das Kalb gewogen und sein Geschlecht bestimmt. Zudem erfolgte eine Vermessung seiner Scheitel-Steiß-Länge, seines Brustumfangs und der Kopfbreite. Des Weiteren wurden seine Rektaltemperatur sowie die Herz- und Atemfrequenz bestimmt. Zusätzlich wurde dem Kalb eine Blutprobe entnommen und im Vollblut auf Laktat sowie im Serum auf verschiedene Stoffwechselparameter untersucht. Die Bestimmung des Blutlaktatgehaltes wurde innerhalb der ersten vierundzwanzig Lebensstunden wiederholt. Im Alter von sieben und vierzehn Tagen wurden die Kälber erneut gewogen und ihre Scheitel-Steiß-Länge und ihr Brustumfang gemessen. Krankheiten und Todesfälle bis zum vierzehnten Lebenstag wurden notiert. Die Dauer der Vorbereitung wirkte sich nicht auf die Körpermaße, die Vitalität, die labordiagnostischen und klinischen Parameter des Kalbes sowie die Totgeburtenrate aus. Der Blutlaktatgehalt des neonatalen Kalbes liegt in den ersten vierundzwanzig Lebensstunden über dem Referenzbereich adulter Rinder und ist unabhängig von der Dauer der Vorbereitung. Das Wachstum des Muttertieres war ebenfalls nicht durch die Dauer der Vorbereitung beeinflusst. Die Rückenfettdicke und Widerristhöhe der Färsen war bei der Abkalbung in den drei Vorbereitungsgruppen gleich. Allerdings wurden mit längerer Vorbereitungsdauer signifikant vermehrt Schwergeburten beobachtet. Mit zunehmendem Geburtsgewicht der Kälber erhöhte sich der Schweregrad der Abkalbungen. Der Schweregrad 2 trat in allen drei Vorbereitungsgruppen gleich häufig auf und wurde ausschließlich durch Lage-, Stellungs- und Haltungsanomalien sowie eine mangelnde Relaxierung des weichen Geburtsweges hervorgerufen. Folglich wurde er nicht von der Dauer der Vorbereitungsfütterung beeinflusst. Mit zunehmendem Schweregrad der Abkalbung traten vermehrt Totgeburten auf. Obwohl der Grad 2 nur 7% der Abkalbungen ausmachte, war er für ein Drittel der aufgetretenen Totgeburten verantwortlich. Die restlichen Totgeburten waren auf Geburten vom Grad 0 und 1 gleichermaßen verteilt. Färsen mit Totgeburten wiesen ante- und peripartal signifikant niedrigere Östradiol-17ß-Konzentrationen auf. Diese Tatsache und das Auftreten von Totgeburten unter problemlosen Geburten deuten auf eine pränatale letale Schädigung des Kalbes oder eine Dysfunktion der Plazenta hin. Weitere Untersuchungen der Plazenta und des Kalbes sind zur Klärung der Zusammenhänge erforderlich. Die Überwachung der Geburtsverläufe und der jungen Kälber war in diesem Betrieb täglich über vierundzwanzig Stunden gegeben. Aufgrund dessen traten eine geringe Totgeburtenrate und wenige Fälle postnataler Morbidität und Mortalität bei den Kälbern auf. Die Dauer der Vorbereitung wirkte sich nicht auf die postnatale Entwicklung der Kälber aus. Zusammenfassend kann somit gesagt werden, dass Totgeburten durch diverse Faktoren verursacht werden. In dieser Studie zeigen sich zwei große Ursachenkomplexe. Zum einen deuten signifikant geringere antepartale Östradiol-Werte und ein Verenden von Kälbern bei problemlosen Geburten auf eine bereits pränatale letale Schädigung des Kalbes oder der Plazenta hin. Zum anderen führen Schwergeburten zu einem Großteil der Totgeburten. Zwar lässt sich das Auftreten von Schwergeburten nicht vollständig verhindern, jedoch reduziert eine kürzere Vorbereitungsdauer ihr Auftreten deutlich. In Verbindung mit einem gezielten, frühzeitigen Eingriff in den abnormen Geburtsverlauf sollte bei einem Großteil der Kälber das Eintreten der perinatalen Mortalität verhindert werden können.In the recent years the incidence of perinatal mortality of calves in calvings of primiparous cows has increased. Dystocia is the main cause for the death of the perinatal calf. The most important factor influencing calving performance is the birth weight of the calf. This study was designed to examine the influence of the duration of the close up period on the growth of the primiparous heifer, its hormonal birth preparation and calving performance. Additionally, this study was to show the influence of the varied duration of the close up period on the calf birth weight, its body measurements, its perinatal viability, clinical parameters and blood serum metabolites. This study was conducted between November 2003 and October 2003 on a Brandenburg dairy in Germany. 433 primiparous, artificially inseminated Holstein heifers were randomly allotted to three groups. A close up ration was fed to group 1 for one week (0-11 days), to group 2 for two weeks (12-16 days) and to group 3 for three weeks (> 17 days). The ration included 6.1-6.6 MJ NEL/kg, 12.1-15.0 % crude protein, 18.6-23.0% crude fibre and 16.5-22.7 starch and other carbohydrates on a dry matter basis. The examination included the measurement of back-fat thickness by ultrasound and collection of a blood sample. The peripartum blood samples were analyzed for estradiol-17ß and progesterone concentrations. A final blood sample was taken immediately after the calving and additionally examined for its concentration of various serum metabolites. Calving difficulty was classified by three numerical scores: 0= no difficulty; 1= light calving assistance and 2= extreme difficulty requiring the use of a mechanical calf puller. Prior to the first feeding of colostrum, the calf was weighed; its sex determined; the crown-rump-length, heart-girth, head width, body temperature, heart-rate and breathing frequency were measured and a blood sample was obtained. The concentration of lactate was measured in the whole blood and the concentration of various metabolites was measured in the blood serum. Within the first 24 hours the blood lactate was measured for a second time. At the ages of seven and fourteen days, the calf was weighed and its body measurements were re-taken. Disease and death cases until the fourteenth day were noted. The duration of the close up period did not influence the body measurements, the viability, the serological or clinical parameters nor the incidence of the perinatal mortality of the calf in this study. The blood lactate concentration of the neonatal calf was higher than the reference values of the adult cattle and was independent of the duration of the close up period. The growth, the back-fat thickness and the height at the withers of the heifers were identical in all three groups after calving. Higher birth weights of the calves lead to more calving difficulties. Although the calf birth weight did not differ between the groups, the longer the close up period, the more birth difficulties were observed. Calving difficulty score 2 was primarily caused by abnormal presentation and reduced relaxation of the maternal soft birth canal and not due to an exceptionally high birth weight. Its incidence was equal in all three groups of the study and therefore it was not influenced by the duration of the close up feeding. Higher calving difficulty scores led to more stillbirths in calves. Although the calving difficulty score 2 accounted for only 7% of the calvings, it led to almost one third of the stillbirths. The other perinatal calf deaths were found in equal parts at the calving scores 0 and 1. The estradiol-17ß concentration in heifers with stillborn calves was significantly lower in the pre and peripartal period. This and the incidence of stillborn calves after a physiological delivery lead to the assumption that there is a prenatal lethal abnormity of the calf or a dysfunction of the placenta. Further investigations and studies of the placenta and the stillborn calf are necessary to evaluate this relationship. The supervision of the parturitions and the calves took place hourly. Based on this there was a very low incidence of stillbirth and postnatal morbidity and mortality of the calves. The duration of the prepartum transition feeding did not lead to any consequences regarding the postnatal development of the calves. In summary, perinatal mortality in calves is caused by a diversity of factors. In this study there were two major causes. On the one hand, heifers with stillborn calves showed a significantly lower prepartal estradiol-17ß concentration and the perinatal calf mortality also existed under easy deliveries. This indicates the existence of a calf which was already prenatal lethally damaged or lethal dysfunction of the placenta. On the other hand, difficult births lead to a large proportion of the perinatal mortalities. It is not possible to completely eradicate the possibility of stillbirths, though it can be significantly reduced by a shorter close up period. In combination with early identification and correction of dystocia, a large number of perinatal calf deaths could be avoided

A Conceptual Analysis

Johne’s disease (JD) is a chronic, production-limiting disease of ruminants. Control programs aiming to minimize the effects of the disease on the dairy industry have been launched in many countries, including Canada. Those programs commonly focus on strict hygiene and management improvement, often combined with various testing methods. Concurrently, organic dairy farming has been increasing in popularity. Because organic farming promotes traditional management practices, it has been proposed that organic dairy production regulations might interfere with implementation of JD control strategies. However, it is currently unclear how organic farming would change the risk for JD control. This review presents a brief introduction to organic dairy farming in Canada, JD, and the Canadian JD control programs. Subsequently, organic practices are described and hypotheses of their effects on JD transmission are developed. Empirical research is needed, not only to provide scientific evidence for organic producers, but also for smaller conventional farms employing organic-like management practices

Sensitivity and Specificity for the Detection of Clinical Mastitis by Automatic Milking Systems in Bavarian Dairy Herds

In automatic milking systems (AMSs), the detection of clinical mastitis (CM) and the subsequent separation of abnormal milk should be reliably performed by commercial AMSs. Therefore, the objectives of this cross-sectional study were (1) to determine the sensitivity (SN) and specificity (SP) of CM detection of AMS by the four most common manufacturers in Bavarian dairy farms, and (2) to identify routinely collected cow data (AMS and monthly test day data of the regional Dairy Herd Improvement Association (DHIA)) that could improve the SN and SP of clinical mastitis detection. Bavarian dairy farms with AMS from the manufacturers DeLaval, GEA Farm Technologies, Lely, and Lemmer-Fullwood were recruited with the aim of sampling at least 40 cows with clinical mastitis per AMS manufacturer in addition to clinically healthy ones. During a single farm visit, cow-level milking information was first electronically extracted from each AMS and then all lactating cows examined for their udder health status in the barn. Clinical mastitis was defined as at least the presence of visibly abnormal milk. In addition, available DHIA test results from the previous six months were collected. None of the manufacturers provided a definition for clinical mastitis (i.e., visually abnormal milk), therefore, the SN and SP of AMS warning lists for udder health were assessed for each manufacturer individually, based on the clinical evaluation results. Generalized linear mixed models (GLMMs) with herd as random effect were used to determine the potential influence of routinely recorded parameters on SN and SP. A total of 7411 cows on 114 farms were assessed; of these, 7096 cows could be matched to AMS data and were included in the analysis. The prevalence of clinical mastitis was 3.4% (239 cows). When considering the 95% confidence interval (95% CI), all but one manufacturer achieved the minimum SN limit of >80%: DeLaval (SN: 61.4% (95% CI: 49.0%–72.8%)), GEA (75.9% (62.4%–86.5%)), Lely (78.2% (67.4%–86.8%)), and Lemmer-Fullwood (67.6% (50.2%–82.0%)). However, none of the evaluated AMSs achieved the minimum SP limit of 99%: DeLaval (SP: 89.3% (95% CI: 87.7%–90.7%)), GEA (79.2% (77.1%–81.2%)), Lely (86.2% (84.6%–87.7%)), and Lemmer-Fullwood (92.2% (90.8%–93.5%)). All AMS manufacturers’ robots showed an association of SP with cow classification based on somatic cell count (SCC) measurement from the last two DHIA test results: cows that were above the threshold of 100,000 cells/mL for subclinical mastitis on both test days had lower chances of being classified as healthy by the AMS compared to cows that were below the threshold. In conclusion, the detection of clinical mastitis cases was satisfactory across AMS manufacturers. However, the low SP will lead to unnecessarily discarded milk and increased workload to assess potentially false-positive mastitis cases. Based on the results of our study, farmers must evaluate all available data (test day data, AMS data, and daily assessment of their cows in the barn) to make decisions about individual cows and to ultimately ensure animal welfare, food quality, and the economic viability of their farm

Efficacy of Broilers as a Method of Face Fly (Musca autumnalis De Geer) Larva Control for Organic Dairy Production

The objective of this study was to evaluate Freedom-Ranger broiler chickens as a method to control face fly (Musca autumnalis De Geer) larvae in cow dung pats on pasture. Ninety-nine pats in three replicates were inoculated with first-instar larvae and exposed to one of four treatment conditions for 3 to 4 days: (1) an environment-controlled greenhouse (GH); (2) pasture without broilers (NEG); (3) pasture with 25 broilers stocked at a low density of 2.5 m2 of outdoor area per broiler (LOW); and (4) pasture with 25 broilers stocked at a high density of 0.5 m2 of outdoor area per broiler (HIGH). Broiler behaviors and weather conditions were recorded twice daily. Survival rates of larvae (mean, 95% CI) were similar for pats in the NEG (4.4%, 2–9%), LOW (5.6%, 3–11%), and HIGH (3.2%, 2–7%) groups, and was greatest for larvae reared in the GH (54.4%, 36–72%) group compared to all other groups. The proportion of broilers observed pasture ranging was 14.0% (6–28%) but was negatively related to solar radiation. Broilers were never observed foraging in pats. Results indicate that use of broilers may not be an effective method for controlling larvae of dung pat breeding flies

Sensitivity and Specificity for the Detection of Clinical Mastitis by Automatic Milking Systems in Bavarian Dairy Herds

In automatic milking systems (AMSs), the detection of clinical mastitis (CM) and the subsequent separation of abnormal milk should be reliably performed by commercial AMSs. Therefore, the objectives of this cross-sectional study were (1) to determine the sensitivity (SN) and specificity (SP) of CM detection of AMS by the four most common manufacturers in Bavarian dairy farms, and (2) to identify routinely collected cow data (AMS and monthly test day data of the regional Dairy Herd Improvement Association (DHIA)) that could improve the SN and SP of clinical mastitis detection. Bavarian dairy farms with AMS from the manufacturers DeLaval, GEA Farm Technologies, Lely, and Lemmer-Fullwood were recruited with the aim of sampling at least 40 cows with clinical mastitis per AMS manufacturer in addition to clinically healthy ones. During a single farm visit, cow-level milking information was first electronically extracted from each AMS and then all lactating cows examined for their udder health status in the barn. Clinical mastitis was defined as at least the presence of visibly abnormal milk. In addition, available DHIA test results from the previous six months were collected. None of the manufacturers provided a definition for clinical mastitis (i.e., visually abnormal milk), therefore, the SN and SP of AMS warning lists for udder health were assessed for each manufacturer individually, based on the clinical evaluation results. Generalized linear mixed models (GLMMs) with herd as random effect were used to determine the potential influence of routinely recorded parameters on SN and SP. A total of 7411 cows on 114 farms were assessed; of these, 7096 cows could be matched to AMS data and were included in the analysis. The prevalence of clinical mastitis was 3.4% (239 cows). When considering the 95% confidence interval (95% CI), all but one manufacturer achieved the minimum SN limit of >80%: DeLaval (SN: 61.4% (95% CI: 49.0%–72.8%)), GEA (75.9% (62.4%–86.5%)), Lely (78.2% (67.4%–86.8%)), and Lemmer-Fullwood (67.6% (50.2%–82.0%)). However, none of the evaluated AMSs achieved the minimum SP limit of 99%: DeLaval (SP: 89.3% (95% CI: 87.7%–90.7%)), GEA (79.2% (77.1%–81.2%)), Lely (86.2% (84.6%–87.7%)), and Lemmer-Fullwood (92.2% (90.8%–93.5%)). All AMS manufacturers’ robots showed an association of SP with cow classification based on somatic cell count (SCC) measurement from the last two DHIA test results: cows that were above the threshold of 100,000 cells/mL for subclinical mastitis on both test days had lower chances of being classified as healthy by the AMS compared to cows that were below the threshold. In conclusion, the detection of clinical mastitis cases was satisfactory across AMS manufacturers. However, the low SP will lead to unnecessarily discarded milk and increased workload to assess potentially false-positive mastitis cases. Based on the results of our study, farmers must evaluate all available data (test day data, AMS data, and daily assessment of their cows in the barn) to make decisions about individual cows and to ultimately ensure animal welfare, food quality, and the economic viability of their farm