The type of lipid supplement has crucial implications for forage particle size in calf starter diets

Table 5 Least square means for oxidative stress indicators in whole blood of dairy calves fed starters containing alfalfa hay with different particle sizes (small vs. long particles) with different lipid supplements (SBO vs. PLF, both 2.5% DM basis) (n = 13 calves per treatment)

Item	Treatments¹				SEM	P-value²
	SP		LP			FPS	Lipid	FPS × Lipid	T	FPS × T	Lipid × T	FPS × Lipid × T
	SBO	PLF	SBO	PLF		FPS	Lipid	FPS × Lipid	T	FPS × T	Lipid × T	FPS × Lipid × T
Glutathione peroxidase, IU/g Hb
d 53	250	247	251	242	4.8	0.60	0.21	0.58
d 73	297	289	299	293	5.1	0.47	0.14	0.88
Overall	278	261	270	269	5.0	0.36	0.19	0.56	0.034	0.57	0.21	0.19
Superoxide dismutase, IU/g Hb
d 53	2,267	2,351	2,240	2,215	83.8	0.34	0.73	0.52
d 73	2,435	2,429	2,414	2,438	92.2	0.78	0.80	0.75
Overall	2,390	2,389	2,374	2,364	91.6	0.54	0.70	0.34	0.052	0.60	0.43	0.27
Malondialdehyde, µmol/L
d 53	2.41	1.81	2.16	1.89	0.093	0.11	0.024	0.39
d 73	4.78	4.13	4.81	3.96	0.144	0.347	0.005	0.22
Overall	3.89	2.90	3.07	2.17	0.132	0.236	0.062	0.78	0.007	0.79	0.093	0.45

¹Treatments: alfalfa hay provided as small particle size supplemented with soybean oil (SP-SBO); alfalfa hay provided as small particle size supplemented with palm fatty acids (SP-PLF); alfalfa hay provided as long particle size supplemented with soybean oil (LP-SBO); alfalfa hay provided as long particle size supplemented with palm fatty acids (LP-PLF)
²Statistical comparisons: Forage particle size (FPS) = small versus long particle sizes; Lipid = soybean oil versus palm fatty acids; FPS × Lipid = interaction between alfalfa hay particle sizes and supplemental lipid; T = time; FPS × T = forage particle size × time; Lipid × T = lipid source × time; FBS × Lipid × T = forage particle size × lipid source × time

ISSN: 2049-1891