Protein restriction during late gestation in beef cow: effects on growth and meat quality of progeny: Doctoral thesis abstract
The objective of this study was determine whether the amount of protein provided to cows during late gestation would affect postnatal growth and lead to changes on glucose regulation, carcass characteristics and meat quality of steer progeny. At 121 d prepartum, 68 multiparous Angus cows were blocked by BW and expected calving date and randomly assigned to low protein level (LP, 6% CP) or high protein level (HP, 12% CP) and were allotted in 12 pens per treatment. After calving, cows were managed together on improved pastures until weaning. Calves were weighed and body measurements were recorded at birth. Blood samples were taken at birth and each 30 d until weaning at 180 d of age. Male calves were maintained as a group after weaning on native range until 23 month of age when individual steers were fed a finishing diet during 84 d before slaughter. Twenty days before the end of the finishing phase, steers were subjected to an intravenous glucose tolerance test. Body weight at birth tended to be great (P = 0.06) and body mass index was greater (P = 0.04) on HP than LP progeny. Maternal dietary protein concentration had no influence on offspring body weight and growth rate during lactation, rearing or finishing phases (P > 0.10). Rib fat thickness of steers was not affected (P = 0.38) by maternal nutrition treatments, however, LM area was greater in HP steers than LP steers at entrance into the feedlot (P = 0.01) and end of finishing phase (P = 0.04). Glucose concentrations was greater (P < 0.001) on LP calves than HP calves from birth to weaning without any change in insulin concentrations (P > 0.10). Insulin-like growth factor concentrations was lower on LP calves at birth (P < 0.05). During the glucose tolerance test at 24 month of age, glucose concentration after intravenous administration decreased faster (P = 0.002) in LP compared to HP steers. Peak of serum insulin concentration was greater (P = 0.04) and serum insulin concentration tended to decrease (P = 0.08) more rapidly in LP compared to HP steers. Hot carcass weight was similar between treatments (P = 0.69), however dressing percentage was increased in HP relative to LP steers (P = 0.01). Tenderness of Longissimus muscle was increased in HP compared to LP steers (P < 0.001). No treatment differences in troponin-t degradation (P = 0.77) and collagen content (P = 0.58) were observed. Muscle fiber diameter was similar in LP and HP steers (P = 0.20), suggesting that increase of LM area in HP steers could be due to muscle hyperplasia. These data demonstrate that low protein during late gestation in bovine dams may affect fetal growth. Low level of protein compromised glucose regulation in early life and alter glucose regulation, enhancing insulin secretion in steer progeny at 24 month of age. The results indicated that level of protein during mid to late gestation does not affect offspring growth but has impacts on carcass composition and meat quality of steer progeny.
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| Format: | Digital revista |
| Language: | eng spa |
| Published: |
Coeditada entre Facultad de Agronomía - Udelar y el Instituto Nacional de Investigación Agropecuaria (INIA)
2020
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| Online Access: | https://agrocienciauruguay.uy/index.php/agrociencia/article/view/1568 |
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