Breed and non-genetic risk factors associated with the prevalence of subclinical mastitis in livestock systems of Arauca, Colombian orinoquia

Figures & data

Figure 1. Red color: location of the department of Arauca, Colombian orinoquia. Circle: area where the farms were sampled.

Figure 2. Cows from the dual-purpose livestock system of Arauca department, eastern Colombia.

Figure 3. Mammary quarters position for milk sampling. RP= right Posterior; LP= left Posterior; RA= right Anterior; LA= left anterior.

Table

Mammary quarter with highest score (RA):	380u
Mammary quarter with lowest score (LP):	310u
Difference:	70u

Table 1. Example of EC results interpretation among mammary quarters.

Right Posterior (RP):	370u
Left Posterior (LP):	310u
Right Anterior (RA):	380u
Left Anterior (LA):	370u

Table

Ni =	i-th modeled probability of having SCM-positive animals.
π =	odds ratio: (1-π) probability of not having the presence of SCM
M =	Pending
X1 =	Effect the age variable (3 to 10 years)
X2 =	Effect the milk production variable (2 to 12 L)
X3 =	Effect the lactation month variable (1 to 7)
X4 =	Effect the body condition variable (1 to 5)
X5 =	Effect the climatic period variable (rainy and dry)
X6 =	Effect the cows number variable (1=7 to 16 cows; 2=17 to 26 cows; 3= > 26 cows)
X7 =	Effect the breed variable (1=Taurus-Indicus; 2=Indicus predominance; 3=composite breed)
X8 =	Effect the calving number variable (1 to 8)
εi =	Accumulated error
βi =	Regression coefficients associated with each independent variable

Table 2. Cow-level prevalence and number of cows with affected mammary quarters in the sample evaluated in the dual-purpose livestock system of Arauca, Colombian orinoquia.

Total sampled cows		481	%
Positive cows		143
Cow-level prevalence			29.7
Affected mammary quarters^1
	1	87	18.1
	2	40	8.3
	3	13	2.7
	4	3	0.6

^a= Cows with 1,2,3 and 4 affected mammary quarters.

Table 3. Prevalence of SCM (%) at level of total mammary quarters and at level of mammary quarters by position (RP, LP, RA, LA) by EC test in a dual-purpose livestock system of Arauca, Colombian orinoquia.

Total mammary quarters sampled		1924	%
Positives		218
Prevalence at the level of total mammary quarters			11.3
Prevalence at the level of mammary quarters by position
Mammary quarters	n	Positives
RP	481	57	11.9
LP	481	54	11.2
RA	481	49	10.2
LA	481	58	12.1

n= number mammary quarters by position; RP= Right Posterior; LP= Left Posterior; RA= Right Anterior; LA= Left Anterior.

Table 4. Prevalence of SCM (%) according to the number of cows in production, daily milk production, lactation month, cow age, climatic period, body condition, calving number, and breed of Arauca, Colombian orinoquia.

Variable	RP	LP	RA	LA	Positive mammary quarters	Positive cows	Sampled cows	%
Number of cows in production
7–16 cows	29	26	22	23	100	63	153	41.2
17–26 cows	11	18	20	21	70	47	194	24.2
>26 cows	17	10	7	14	48	33	134	24.6
Daily milk production/cow
2 to 5 L	29	25	25	28	107	69	237	29.1
6 to 12 L	28	29	24	30	111	74	244	30.3
Lactation month
1–3 months	44	37	34	44	159	104	327	31.8
More than 3 months	13	17	15	14	59	39	154	25.3
Cow age
3 and 4 years	21	15	19	19	74	46	153	30.1
5 years	16	18	11	16	61	38	153	24.8
6 or more years	20	21	19	23	83	59	175	33.7
Climatic period
Rainy	43	40	36	47	166	104	411	25.3
Dry	14	14	13	11	52	39	70	55.7
Body condition
2.5–3.5	31	28	21	34	114	75	208	36.1
3.6–4.5	26	26	28	24	104	68	273	24.9
Calving number
1	16	11	15	16	58	38	116	32.8
2	18	20	16	13	67	46	165	27.9
3	10	10	10	12	42	25	92	27.2
>4	13	13	8	17	51	34	108	31.5
Breed
Taurus-Indicus	34	31	25	30	120	78	275	28.4
Indicus predominance	21	20	24	26	91	60	184	32.6
Composite breed	2	3	0	2	7	5	22	22.7

RP= Right Posterior; LP= Left Posterior; RA= Right Anterior; LA= Left Anterior.

Table 5. Odds ratios of the variables included in the logistic regression for the associated factors with the SCM prevalence in dual-purpose livestock systems of Arauca, Colombian orinoquia.

Regressor variables	OR	Wald LI-LS (95%)	p-value
Non-genetic factors
Age	1.1	0.84–1.44	NS
Calving’s	0.96	0.7–1.32	NS
Lactation	0.85	0.72–1.01	NS
Body condition	0.29	0.11–0.72	0.008
Period	2.5	1.23–5.06	0.011
Number of cows^a
7 a 16	1.56	0.86–2.85	NS
17 a 26	0.95	0.56–1.62	NS
Milk production	0.93	0.82–1.07	NS
Genetic factors
Breed^b
Taurus-Indicus	0.72	0.46–1.12	NS
Composite breed	0.27	0.09–0.88	0.029

OR: odds ratio; Wald LI-LS (95%): Wald confidence limits to 95%; ^a = Reference point group 3 (> 26 cows).

b = Reference point group 2 (Indicus predominance); NS = Not-significant.

Data availability statement

Data is available upon reasonable request to the second author.