Abstract

Reproductive wastage is a significant cause of productivity loss in New Zealand deer herds. This study investigated the impact on reproductive performance of red deer hinds fed swedes over winter. Forty rising-two-year-old and 40 mixed-aged pregnant hinds were drafted into two groups each and grazed for 100 days over winter on either a swede forage crop or pasture. Hinds were blood sampled regularly, weighed fortnightly and pregnancy scanned monthly. Blood samples were analysed for blood urea nitrogen and indicators of liver damage. Swede forage crops were sampled for nutrient and glucosinolate concentrations. No significant differences in hind foetal loss were found between the two wintering systems or two age classes. Swede glucosinolate concentrations levels were above thresholds considered dangerous for animal consumption but no liver damage was observed. Blood urea nitrogen levels did not differ between the swede- and pasture-fed hind groups until day 80, which was 10 days after the swede groups were transferred to another swede crop, when blood urea nitrogen levels were significantly lower in the swede groups. This research indicated that grazing on swedes did not influence reproductive wastage in this instance. However, the effect of low protein intake over an extended period during pregnancy needs to be investigated further.

BR, Thompson, DR Stevens, MA Petit, and GW Asher

New Zealand Journal of Animal Science and Production, Volume 78, Lincoln, 165-169, 2018