Abstract
Introduction: The overall goal of this study is to understand the interaction between macro and micro mineral metabolism in growing sheep and goats. The present abstract provides first preliminary data on end points in performance, serum and bone parameters.
Animals, materials and methods. Two consecutive studies were conducted over a period of 28 days on either 18 East Friesian Milk Sheep (mean age 3 months, mix-sex) or 18 Saanen Goats (mean age between 3.5 and 4 months, mix-sex). The animals were fed a diet containing straw and concentrate. The mixed feedstuff was supplemented with either no mineral P (Group P-), or no mineral Ca (Group Ca-) or according to recommendations for both elements (Control group) [1]. Sampling (serum) and data collection (zootechnical data, bone density via pQCT of two points on the left metatarsus) occurred on days 0 and 28, respectively. Data analysis comprised two-way ANOVA (diet, sex, interaction) and the Student-Newman-Keuls-Test (threshold for type I-error P≤0.05). This study was approved by the Cantonal Veterinary Office of Zurich, based on the animal welfare law of Switzerland (approval ZH 140/2020).
Results and discussion: Mean P and Ca intake were 1.44±0.04 and 4.96±0.13 (P-), 1.78±0.10 and 2.68±0.15 (Ca-), as well as 1.78±0.22 and 4.98±0.62 (Control) g/day in goats, respectively. Associated intake levels for sheep were 1.77±0.14 and 4.82±0.37, 2.82±0.42 and 2.60±0.39, as well as 2.76±0.34 and 4.84±0.59 g/day, respectively. Varying mineral supply affected F:G (feed:gain) of goats and sheep, however, the first responded with increased F:G (5.21, 4.3, 4.24 for P-, Ca- and Control) due to compensatory feed intake in P- and Ca- animals (0.73, 0.71, 0.68 kg/d for P-, Ca- and Control) (P=0.001, SEM=0.023), whereas the latter showed improved F:G (3.34, 3.40, 4.45 for P-, Ca- and Control) via increased gain (0.218, 0.204, 0.167 kg/d for P-, Ca- and Control) at stable feed intake in treatment groups compared to control, though this was not statistically confirmed (P=0.07, SEM=0.029).
Mean concentration of zinc in serum declined by 0.079 mg/L in both the Ca- and P-sheep from d0 to d28, while it was increased in Control (+0.177) (P = 0.0026, SEM=0.08) and not affected in any group of the goats (P=0.772, SEM=0.099).
Mean 1,25OH-vitamin D in serum increased in Ca- goats (+50.1pmol/l) and decreased substantially in P- goats (-76.38pmol/l) with a slight decrease in the Control group (-9.48 pmol/l) (P=0.07, SEM=59.17). In sheep, all groups reacted in an increased 1,25OHVitaminD (+72.74, +190.36, +163.74 pmol/l for P-, Ca- and Control) (P=0.34, SEM=98.27). An increase in mean trabecular density in the distal metatarsus was detected in goats in Group P- (+44.46mg/ccm) and Control (+9.18mg/ccm), while it decreased in Ca- (-18.09 mg/ccm), (P=0.39, SEM=59.249). In sheep it increased in P-, while it decreased in Ca- and Control (15.97, -37.56, -32.0mg/ccm for P-, Ca- and Control) (P=0.01, SEM=21.838). Conclusion: Reduced supply with mineral P and Ca appeared to initiate a state of deficiency in goats, which was compensated by total feed intake, especially in P- animals. Sheep, on the other hand, appeared to grow with higher efficiency in response to reduced P and Ca supply to control. Further data and laboratory analysis are in progress to understand the observed effects during the experiment, including the reduced serum Zn status in P- and Ca- sheep
Schulz, Johanna