Abstract #250

Section: Production, Management and the Environment
Session: Production, Management & the Environment II
Format: Oral
Day/Time: Monday 4:00 PM–4:15 PM
Location: 324

# 250
Nutritional recovery strategies from severe nutrient restriction alter milk and blood parameters of dairy cows.
V. Fischer^*1, D. Werncke¹, F. A. Schmidt², A. Thaler Neto², ¹Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil, ²Universidade do Estado de Santa Catarina, Lages, SC, Brazil.

This work aimed to investigate the effect of different nutritional strategies used in the recovery from severe nutrient restriction on milk and blood parameters. Twelve Holstein cows (milk yield, MY, 18.9 ± 5.5L/day; parity 2.7 ± 1.6; days in milk 146 ± 50; body condition score, BCS, 2.7 ± 0.3 and body weight, BW 575 ± 70 kg) received a diet that supply 100% of energy and protein requirements on d 1 to 13 (NRC, 2001), were restricted in 50% of their energy and protein requirements on d 14 to 17 and, they were assigned to one of the following treatments: full supply of only energy (100E+50P), full supply of only protein (50E+100P) or full supply of both energy and protein (100E+100P) requirements on d 18 to 24. Milk and blood measurements were taken on the last day of recovery phase. Diets were formulated with different proportions of corn silage, Tifton hay, soybean meal, toasted soybean. Data were analyzed as a Latin square design (12 cows, 4 Latin squares, 3 periods, 3 treatments). Cows supplied with 100E+100P showed higher values for MY and stability than the other cows. Cows supplied with 100E+100P showed higher values for BCS, BW but lower values for FPR, MUN, albumin than cows supplied with 50E+100P. Cows supplied with 100E+50P presented higher values for MY, BCS, BW but lower values for FPR, MUN and albumin than cows supplied with 50E+100P. There were no differences (P > 0.10) for haptoglobin and BHBA concentrations. Only full supply of both nutrients overcomes the adverse effects of nutrient restriction on MY, stability and MUN. Table 1.

Item	Treatment			SE
Item	100E+100P	100E+50P	50E+100P	SE
MY (kg/d)	19.6^a	14.4^b	12.1^c	1.4
BCS (1 to 5: 1 = emaciate, 5 = obese)	2.6^a	2.7^a	2.4^b	0.1
BW (kg)	525^a	521^a	471^b	6.9
Fat to protein ratio in milk (FPR)	1.2^a	1.2^a	1.4^b	0.02
Milk urea nitrogen (MUN, mg/d)	12.1^b	2.1^c	17.7^a	0.8
Milk stability (°GL)	73.2^a	69.8^b	62.2^c	1.5
Haptoglobin (g/L)	0.46^a	0.30^a	0.92^a	0.25
Albumin (g/L)	30.5^b	31.2^ab	32.5^a	0.5
BHBA (mmol/dL)	0.4^a	0.4^a	0.5^a	0.02

^a,b,cMeans in the same row followed by different letters are distinct (P < 0.05).

Key Words: blood traits, nutritional restriction, milk composition