Effects of increasing dietary zinc sulfate fed to gestating ewes: II. Milk somatic cell count, microbial populations, and fatty acid composition

The objective of the research was to evaluate effects increasing dietary Zn sulfate concentration for primiparous gestating ewes on subsequent milk SCC, intramammary microbial identifications, and fatty acid composition. Commercial white-face (WF; n = 27) black-face (BF; 24) (age ≈18 mo; BW 87.48 ± 8.37 kg) were sorted into breed-type groups within ranked by BW, then, they randomly divided 3 supplement treatment groups: CON (n 13; 40 mg/kg Zn; ≈1 × NASEM recommendations), Zn500 21; 500 ≈4 Zn1000 17; 1,000 ≈7 recommendations). Treatments administered in Zn-fortified pelleted alfalfa (0.45 kg/ewe per day) fed from 87.5 8.9 d gestation until parturition. Milk traits collected at parturition (d 1 lactation), ≈30 lactation, lamb weaning (≈90 lactation) assessed as repeated measures with fixed treatment, breed type, litter size. type interaction affected ewe logSCC (P 0.01), Zn500, BF had greater than WF (5.90 0.08 vs. 5.46 0.08; P < 0.01). However, types did not differ between treatments ≥ 0.92). Ewe greatest 0.01) (6.03 0.06), intermediate (5.72 0.06; 1), least 30 lactation (5.21 0.06). Intramammary infections common samples (77%) (47%) based culture-based identifications. most frequently identified species included Bacillus spp. Staphylococcus Black-face concentrations C16:1 (1.78 mg/100 1.39 mg 100 total acids), C17:1 (0.86 0.76 C20:4 (0.28 0.24 acids; ≤ 0.04) ewes. Including diets beyond recommendations mid late no effect pathogens identified, or findings indicated there may be important differences utilization requirements affecting inflammation.