Publikationsdatenbank

Calving prediction and evaluation of calving ease after medical treatment in Holstein-Friesian heifers (2020)

Art

Hochschulschrift

Autor

Lange, Katrin Susanne (WE 19)

Quelle

Berlin: Mensch & Buch Verlag Berlin, 2020 — II, 82 Seiten

Sprache

Englisch

Verweise

URL (Volltext): https://refubium.fu-berlin.de/handle/fub188/28560

Kontakt

Tierklinik für Fortpflanzung

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Abstract / Zusammenfassung

The overall objectives of this thesis were to predict calving via direct observation and to evaluate calving ease after medical treatment in Holstein Friesian heifers and their calves. Calving is the crucial event in the life cycle of a dairy cow. Recognizing the beginning of calving, especially the beginning of stage 2 of calving, facilitates calving management and enables an optimal start for cow and calf. We aimed to predict calving dispensing with technical equipment. Prior to the study six signs of imminent parturition were identified based on a literature research and systematic assessment. We intended to develop a reliable prediction method with regard to the second study. Reliable calving prediction facilitates conducting a field study whereas the beginning of stage 2 of calving is important to recognize. Hence, the first study examined physical and behavioral alterations in heifers shortly before parturition. We intended to predict calving without technical equipment via direct observation and evaluation of relaxation of the pelvic ligaments and teat filling. In a first experiment, the interobserver reliability of SIP was tested. Except for one case, cohen’s kappa results were good or very good. During the second experiment SIP was tested under field condition. Thirty-seven heifers from day 267 ± 4 d of parturition were observed hourly for 15 sec each. If one SIP was seen, it was ticked off in a list. Additionally, the relaxation of the pelvic ligaments and teat filling was evaluated every 12 hours. Compared to a precalving control period (day 4 for before calving) tail raising, clear vaginal discharge and bloody vaginal discharge were significantly more likely to occur 24 h before calving. Lying lateral with abdominal contractions was excluded because it was not observed during the control period. Additionally, an equation was built to predict the hours until parturition. In a first version the absence or presence of every SIP except turning the head toward the abdomen was included. In a second version, hours until parturition were estimated with the factors days of gestation, tail raising and clear vaginal discharge. As SIP are animal specific, they are no precise instrument for calving prediction. However, the equation is only a first approach to develop a formula, that might be included in a calving prediction application. Further research is necessary to identify pattern in occurrence of SIP and to ensure a reliable basis for calving prediction. A cut-off value of > 5 points combining PL double weighted and TF resulted in a negative predictive value of 96.8 whereas sensitivity was 68.97 and specificity 87.91. Hence, the examination of PL and TF was not satisfying for predicting calving within the next 12 hours. Consistent with previous findings, results for excluding calving were considerably higher. Overall, the prediction of stage two of calving via direct observation and evaluation of PL and TF was not sufficient. Nevertheless, further research into the occurrence of SIP is warranted to enable a solid basis for an equation as a prediction tool. The second study was conducted to examine the effects of DNH on calving ease in heifers and calves. A study protocol with a concise timeline was developed to enable comparable results. The beginning of stage two was defined as the first time one or both of the calves’ feet became visible. Thirty minutes later, DNH or a Placebo (NaCl) was administered to the heifer subcutaneously. If calving was completed during the next 30 minutes, the case was recorded as unassisted. Duration of calving was measured and blood samples were drawn for cortisol and lactate concentration in heifers and calves, respectively. If calving was not completed 60 min after beginning of stage 2, calving assistance was conducted. A mechanical calf puller was utilized to ensure a comparable extraction method. Furthermore, a digital force gauge was attached to the calves’ feet and the mechanical calf puller. Pulling force was measured during calving assistance. Finally, blood samples were drawn, heifers were examined for vaginal lacerations and calves were supplied with colostrum. Data from 83 calvings were included in the final analyses. Nearly 50 % of heifers treated with DNH and 38 % of heifers treated with PLA calved without assistance (P = 0.524). Duration of calving in both groups did not differ significantly, but a tendency was found that calving assistance was shorter in heifers treated with DNH (3 min 11 s ± 1 min 47 s) compared to PLA (3 min 59 s ± 3 min 5 s; P = 0.075). There was a significant difference of concentration of cortisol before and after calving in both treatment groups. A difference in the increase of cortisol concentration after calving between treatment groups was not found (P = 0.257). The authors speculate that the stressful event itself superimposed the effect of DNH during parturition. The area under the curve was estimated to enable comparison of pulling force data. The AUC was significantly smaller in the DNH treatment group compared to PLA (P = 0.035). This result indicates the influence of DNH on the calving process. We assume that the widening and softening of the birth canal facilitates the delivery of the calf. The vitality of the newborn calves was evaluated by appliance of the APGAR score. Moreover, l-lactate concentration in blood of the calves was measured directly after calving with a validated handheld meter. Both parameters were not influenced by the treatment group. Overall, the first study clearly demonstrated that further research is warranted to achieve a reliable prediction method. There is a rapid and ongoing progress in the development of technical devices for calving prediction. Still, a better understanding of behavior and physical alterations before calving is essential. A measurable effect of DNH on pulling force was found in the second study. We assume that this means an improvement in the calving process for the dam. For evaluation of stress in dam and calf, further research is warranted.e of the APGAR score. Moreover, l-lactate concentration in blood of the calves was measured directly after calving with a validated handheld meter. Both parameters were not influenced by the treatment group.