Influence of nutrition during late pregnancy on dam condition, foetal growth and gestation length
| Autor: | R. C. Mulley, M. J. Casey, G. W. Asher |
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| Rok vydání: | 2003 |
| Předmět: | |
| Zdroj: | NZGA: Research and Practice Series. 9:57-63 |
| ISSN: | 2463-4751 0110-8581 |
| DOI: | 10.33584/rps.9.2002.3412 |
| Popis: | Many aspects of the relationship between nutrition and reproductive performance of red deer hinds are poorly understood. One such example is the feed requirements of hinds during the late stages of pregnancy, for which there is considerable diversity of opinion. The present study aimed to relate feed intake of hinds during the last trimester of pregnancy to dam body condition, foetal development and calf growth. Across 3 years, multiparous (n=33) or primiparous (n=18) hinds with known conception dates were housed in individual pens from days 150 to 220 of pregnancy, during which time they were each offered one of three (H, M and L) daily allowances of pelletised rations. Hinds were returned to pasture at day 220 and calving was closely monitored. Liveweight, body condition score (BCS), and lactation score (LS) were recorded weekly from day 150 through to calf weaning at 12 weeks of age. Additionally, hinds in the first year of study underwent CT scans on days 150 and 215 of pregnancy to assess compositional changes of the dam and conceptus. Mean daily ad libitum intakes of H hinds increased from 1.8 to 3.2 kg DM (0.6 to 0.9 MJME/kg0.75) between days 150 and 220. Those of restricted M and L hinds peaked at 1.8 and 1.6 kg DM, respectively, by day 220. This was reflected in significant treatment effects on liveweight gain and change in BCS and LS by calving. CT scans indicated a significant treatment effect by day 215 on the mass of hind tissues and a non-significant trend on conceptus weights. There were no discernable treatment effects on calf birth weights. However, there was an unexpectedly wide spread in calving dates that reflected considerable variation in gestation length. Gestation length was significantly negatively correlated to change in hind liveweight (but not BCS) between days 150 and 220 of pregnancy. Of three neonatal calf mortalities, none were related to dystocia or non-viability. Subsequent growth rates of surviving calves did not reflect prior treatment of their dams, although variation in birth date influenced weights at specific dates. It is concluded from this study that while variation in nutrition of hinds during the last trimester may influence foetal development, variation in gestation length compensates to ensure optimisation of birth weight. Keywords: gestation, nutr ition, pregnancy, red deer |
| Databáze: | OpenAIRE |
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