Presence of pathogen DNA in milk harvested from quarters is associated to changes in cows’ milk yield and composition

Table 5 Least squares means¹ (standard error) of milk traits for the fixed effect of pathogen group²

Trait³	Absent pathogens	Major pathogens		Minor pathogens		Other pathogens
Trait³	Absent pathogens	≤ 2 quarters	≥ 3 quarters	≤ 2 quarters	≥ 3 quarters	≤ 2 quarters	≥ 3 quarters
SCS	2.29 (0.13)^c	3.23 (0.14)^ab	3.68 (0.19)^a	2.73 (0.16)^bc	3.09 (0.24)^abc	3.12 (0.31)^abc	3.59 (0.38)^ab
DSCC, %	57.50 (1.12)^b	64.70 (1.18)^a	65.00 (1.63)^a	60.40 (1.38)^ab	62.40 (2.07)^ab	63.20 (2.64)^ab	64.40 (3.16)^ab
DSCS	1.46 (0.15)^c	2.58 (0.16)^ab	3.01 (0.22)^a	1.96 (0.19)^bc	2.36 (0.28)^abc	2.42 (0.36)^abc	2.90 (0.43)^ab
Milk yield, kg/d	25.90 (0.47)	24.50 (1.13)	24.90 (0.70)	25.30 (0.59)	24.90 (0.70)	24.50 (1.13)	26.60 (1.35)
Fat, %	3.84 (0.05)	3.90 (0.06)	3.79 (0.08)	3.93 (0.06)	3.88 (0.10)	4.10 (0.124)	4.06 (0.15)
Protein, %	3.63 (0.02)	3.66 (0.02)	3.64 (0.03)	3.64 (0.03)	3.63 (0.04)	3.72 (0.06)	3.71 (0.07)
Casein, %	2.90 (0.02)	2.92 (0.02)	2.88 (0.03)	2.90 (0.03)	2.89 (0.04)	2.98 (0.05)	2.97 (0.06)
Casein index	0.798 (0.001)^a	0.797 (0.001)^ab	0.791 (0.001)^b	0.796 (0.001)^ab	0.796 (0.002)^ab	0.798 (0.002)^ab	0.800 (0.001)^ab
Lactose, %	4.77 (0.01)^a	4.77 (0.01)^a	4.67 (0.02)^b	4.76 (0.01)^a	4.73 (0.02)^ab	4.80 (0.03)^a	4.80 (0.04)^a

¹Values with different superscripts within trait differ significantly (P ≤ 0.05)
²Description of groups is provided in Tables 1 and 2
³SCS Somatic cell score, calculated as SCS = 3 + log₂(SCC/100,000), where SCC is somatic cell count (cells/mL), DSCC Polymorphonuclear neutrophils and lymphocytes (%) out of the total SCC, DSCS Differential somatic cell score, calculated as DSCS = 3 + log₂(DSCC_N/100,000), where DSCC_N is the combined number of polymorphonuclear neutrophils and lymphocytes in milk (cells/mL)

ISSN: 1746-6148