Effect of two energy levels during the last third of gestation of beef cows on characteristics of the placenta and offspring at birth.
The objective of the present study was to evaluate two energy intake levels during the last third of gestation of beef cows was evaluated on placental characteristics, ethological and morphometric variables of their female calves. Thirty-one British multiparous cows, inseminated at fixed time and carrying females were assigned on Day –90 (Day 0=delivery) to two levels of energy intake until delivery: i- 125% of the requirements (ALTA; n=15) and ii- 75% of the requirements (BAJA; n=16). In the cows, live weight (PV), body condition score (CC), concentration of unesterified fatty acids (AGNE) and insulin were recorded. Placenta (weight, number of cotyledons and placental efficiency) was characterized and morphometric and behavioural measures were evaluated within the first 24 hours of calf life. At calving, BAJA cows had a higher concentration of AGNE (0.45±0.03 vs 0.27±0.03 mmol/L, P<0.01) and lower insulin (8.83±0.73 vs 10.88±0.71 uIU/ml, P<0.03), as well as lower PV (478±15.4 vs 521±11.8 kg, P<0.01) and CC (3.9±0.08 vs 4.5±0.06 u; P<0.01) compared to ALTA cows. The characteristics evaluated in the placentas were not affected by treatments, nor was the PV of the calves at birth. In the same way, none of the morphometric or behavioural variables was significantly affected by the treatments. In the present experiment, the undernourished cows mobilized body reserve during the last third of gestation to protect the integrity of their offspring, verified by the absence of differences in the parameters evaluated. Possibly, cows grazing native pastures develop mechanisms of accumulation and mobilization of body reserves that allow them, at least for the conditions of the present study, to overcome periods of forage shortage as an adaptation strategy.
| Main Authors: | , , , , |
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| Format: | Digital revista |
| Language: | spa |
| Published: |
Asociacion Latinoamericana de Produccion Animal
2020
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| Online Access: | https://ojs.alpa.uy/index.php/ojs_files/article/view/2781 |
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