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Repeated regroupings affect body and reproductive development and energetic metabolism.

M. Moratorio

Events

06-24-2020

Abstract:

288
Repeated regroupings affect body and reproductive development and energetic metabolism.
M. Moratorio*1, A. Amil1, M. Pedrozo1, R. Ungerfeld2, M. Carriquiry3, C. Fiol1. 1Departamento de Bovinos, Facultad de Veterinaria, Universidad de la Rep�blica Montevideo, Uruguay, 2Departamento de Fisiolog�a, Facultad de Veterinaria, Universidad de la Rep�blica Montevideo, Uruguay, 3Departamento de Producci�n Animal y Pasturas, Facultad de Agronom�a, Universidad de la Rep�blica Montevideo, Uruguay.

The aim was to determine the effects of social regrouping (SR) on body and reproductive development and energetic metabolism in dairy heifers. Holstein heifers (153.3 � 16.1 kg, 11 mo old) were allocated to 2 homogeneous groups according to BW, age and farmer origin: 1) Control (CON; n = 14 + 5 “fixed”) and 2) Regrouped (RG; n = 14 + 5 “exchanged”), in which “exchanged” were switched for 5 unknown heifers every 21 d (total = 10 SR; Day 0 = SR 1). In each SR the BW, ADG, withers height (WH) and BCS were registered, blood samples were taken for IGF-1, glucose, NEFA and albumin determinations. In addition, date at first heat was registered. Body development, IGF-1 and metabolites data were analyzed by PROC GLIMMIX, and days to first heat were compared with PROC Lifetest. Body weight and ADG changed across SR (Table 1). Control heifers had greater WH and BCS in SR 8 (122 vs 120 cm � 1.8), 9 (123 vs 120 cm � 1.8) and 10 (124 vs 122 cm � 1.8), and in SR 4 (3.5 vs 3.2 � 0.15) and 5 (3.4 vs 3.1 � 0.15), respectively, than RG. Insulin growth factor-1 concentration was greater in CON than RG heifers (Table 1), and CON had greater IGF-1 concentrations in SR 3 (207.4 � 20 vs 97.4 � 12 ng/mL), 5 (184.5 � 17 vs 97.4 � 12 ng/mL), 7 (175.9 � 17 vs 122.4 � 14 ng/mL) and 9 (193.5 � 18 vs 137 � 15 ng/mL) than RG. Glucose and albumin concentrations of CON were greater than RG heifers (Table 1), and glucose was higher in CON than RG heifers in SR 3 (4.7 vs 4.4 mmol/L � 0.1) and 6 (4.2 vs 3.7 mmol/L � 0.1). In contrast, NEFA was greater in RG than CON heifers (Table 1), and RG had greater NEFA than CON in SR 3 (0.6 � 0.09 vs 0.3 � 0.06 mmol/L), 5 (0.5 � 0.08 vs 0.3 � 0.05 mmol/L) and 7 (0.4 vs 0.3 mmol/L � 0.05). Control heifers showed first heat earlier than RG heifers (93 � 9 vs 126 � 14 d; P < 0.05). In conclusion, frequent SR negatively affected body and reproductive development and energetic metabolism.Table 1.

ItemGroupSEMP-value
CONRGGroupSRGroup � SR
BW, kg266.7259.95.4ns<0.01ns
ADG, kg/d0.820.790.02ns<0.01ns
WH, cm115.9115.41.8ns<0.010.01
BCS3.43.30.13ns<0.01<0.01
IGF-1, ng/mL177.4116.510.5<0.010.02<0.01
Glucose, mmol/L4.34.20.070.04<0.010.05
Albumin, mmol/L30.028.60.60.01<0.01ns
NEFA, mmol/L0.300.350.040.04<0.01<0.01

Keywords: social regrouping, heifer.

Biography: I'm graduate student working on my Master thesis.