Investigation of Body Development in Growing Holstein Heifers With Special Emphasis on Body Fat Development Using Bioelectrical Impedance Analysis.

This study analyzed skeletal development, body condition, and total body fat development of growing heifers. A total of 144 female primiparous Holstein cattle from four commercial dairy farms with different degrees of stillbirth rates were examined during the rearing period. This included measurements in body condition, fat tissue, metabolic, and endocrine factors. Pelvic measurements and the sacrum height were analyzed to assess skeletal development. The body condition was classified via body condition scoring, bioelectrical impedance analysis (BIA), back fat thickness measurements, and the body mass. For the first time, BIA was used as an appropriate method to evaluate the fat tissue content of cattle throughout the rearing period. This analysis technique can be performed on heifers aged 8-15 months. Throughout that period, the fat content decreased while the skeletal development increased. In addition, high free fatty acid concentrations in serum of the animals with high frame development were found, supporting our hypothesis that stored energy of body fat deposits is used for skeletal growth. Furthermore, we were able to demonstrate complex endocrine relationships between fat metabolism and skeletal growth by using specific markers, such as leptin, insulin growth factor-1 (IGF-1), and estradiol (E2). Food analysis showed high crude protein (CP) levels in the total mixed ration above recommendation for daily protein intake of all farms. However, there was a positive correlation between CP and the body frame measurements in our study. In summary, we established a novel regression formula for BIA analysis ("BIA-Heine") in heifers to evaluate the body composition throughout different ages and physiological stages in the development of heifers. This special formula allows the evaluation of fat tissue without a whole-body analysis and therefore provides an innovative technique for animal welfare support.

[Effect of different pain management protocols on the health status of German Holstein heifer calves undergoing hot iron disbudding]. / Einfluss der thermischen Enthornung mit unterschiedlichem Schmerzmanagement auf die Gesundheit von Kälbern.

OBJECTIVE: Hot iron disbudding of calves is a stressful and painful procedure. Previous parts of an ongoing comprehensive study on disbudding in dairy calves dealt with various types of pain management and the direct effects of the procedure on physiological, biochemical and behavioral processes. The goal of this study part was to investigate the effects of the disbudding procedure per se, pain management and the age of the calf at the time of disbudding on the health status of the calf. MATERIALS AND METHODS: A total of 337 German Holstein heifer calves were used for this prospective, randomized and triple-blinded study. The calves were disbudded at 4-10 days or at 15-28 days of age. Each calf was randomly assigned to one of 9 treatment groups, which differed with respect to pain management (sedation, local anesthesia, nonsteroidal antiinflammatory drugs, placebo). All but the sham-disbudded calves underwent hot iron disbudding and all calves were monitored clinically before and until 4 weeks after the procedure. The findings were analyzed using valuation scores and a threshold model of the SAS software. RESULTS: Disbudding exhibited adverse effects on respiratory health. Calves undergoing sham disbudding experienced the lowest incidence of respiratory disease and calves that did not receive any anesthesia or pain medication displayed the highest frequency. All treatments showed mitigating effects on the incidence of respiratory tract diseases, however the effects varied with the type of pain management. Fever was less common in calves that were disbudded early in life than calves that underwent disbudding at an older age. CONCLUSION: Disbudding of young calves poses a risk to respiratory health. If breeding of polled offspring is not possible or when farming of horned cattle is not feasible, the risk of respiratory disease induced by disbudding can be minimized by adequate pain management. Disbudding of very young calves is feasible and recommended. CLINICAL RELEVANCE: The present study underlines the importance of optimal pain management during disbudding of dairy calves.

Ultrasonographic imaging of abomasal milk clotting and abomasal diameter in healthy and diarrheic calves.

In case of diarrhea calves are treated with oral rehydration solutions (ORS), which are known to increase abomasal pH and inhibit milk clotting in vitro. Nevertheless, recent studies have shown that ORS with HCO3(-) ≤ 62 mmol/L do not interfere with abomasal milk clotting in healthy calves. However, in diarrheic calves, feeding ORS and milk simultaneously may disturb abomasal curd formation and exacerbate diarrhea due to faster abomasal passage of ingesta. Therefore, the aim of the present study was to ultrasonographically examine abomasal milk clotting and diameter after feeding milk and milk replacer (MR) with and without ORS to healthy and diarrheic calves. Abomasal curd formation and diameter in healthy and diarrheic calves were ultrasonographically imaged before and after feeding milk, MR and ORS prepared in milk or MR. Feeding mixtures of milk or MR with ORS did not cause any remarkable differences in the ultrasonographic images of abomasal content. Moreover, abomasal milk clotting was not disturbed due to diarrhea. Statistically significant differences of abomasal diameter after feeding between healthy and diarrheic calves indicated that abomasal emptying is delayed in diarrheic calves. Hence, further studies are needed to determine reasons for decelerated abomasal passage in calves suffering from diarrhea.