Observational study on application of a selective dry-cow therapy protocol based on individual somatic cell count thresholds

Figures & data

Table 1. Description of cow population characteristics included into the study.

Factor	Class	N, %	Frequency, %
			No treatment	Treatment A^1	Treatment B^2
Herd	A	216 (10.5)	79.6	11.1	9.3
	B	384 (18.6)	27.1	51.0	21.9
	C	496 (24.0)	49.2	20.2	30.6
	D	536 (26.0)	44.8	17.2	38.1
	E	432 (20.9)	49.1	20.4	30.6
Parity (n)	1	1072 (51.9)	54.5	17.2	28.3
	2	652 (31.6)	44.2	26.4	29.4
	≥3	340 (16.5)	29.4	42.4	23.2
Dry period length, days	1–45	266 (12.9)	54.5	19.9	25.6
	46–60	966 (46.7)	51.2	17.4	31.4
	61–75	592 (28.7)	40.4	29.2	30.4
	≥75	240 (11.6)	38.8	44.2	17.1
Teat sealant	Yes	1643 (70.9)	47.5	19.1	33.4
Total		2064	47.1	24.2	28.7

¹ Treatment A: cefalonium 250 mg. Cepravin™, MSD Italy.

² Treatment B: cefalexin 504.7 mg Rilexine HL™, Virbac Italy.

Table 2. Distribution of quarters by their infection status and treatment at drying-off.

Drying-off status^1	N (%)	Frequency, %
		No treatment	Treatment A^5	Treatment B^6
Negative	999 (49.1)	54.9^a,2	19.3^b	25.8^b
IMI^4	531 (26.0)	20.6^a	31.4^b	29.4^b
Transient IMI	506 (24.8)	41.5^a	27.7^b	30.8^a,b
Total	2036^3	47.1	24.2	28.7

¹ Infection status defined as reported in Table S1 (Supplementary Data).

² Column means with different letters are statistically different at χ² test (α < 0.05).

³ 28 blind quarters were not reported in the table.

⁴ Intramammary infection.

⁵Treatment A: cefalonium 250 mg. Cepravin™, MSD Italy.

⁶Treatment B: cefalexin 504.7 mg Rilexine HL™, Virbac Italy.

Table 3. Distribution of quarters by their infection status and treatment after calving.

Post-calving status^1	N (%)	Frequency, %
		No treatment	Treatment A^5	Treatment B^6
Negative	1004 (49.3)	53.4^a,2	20.2^b	26.4^b
IMI^4	477 (23.5)	37.9^a	30.6 ^b	31.4^b
Transient IMI	553 (27.3)	25.9^a	31.4^a	30.9^a
Total	2034^3	47.1	24.2	28.7

¹ Infection status defined as reported in Table S1 (Supplementary Data).

² Column means with different letters are statistically different at χ² test (α < 0.05).

³ 30 blind quarters were not reported in the table.

⁴ Intramammary infection.

⁵Treatment A: cefalonium 250 mg. Cepravin™, MSD Italy.

⁶Treatment B: cefalexin 504.7 mg Rilexine HL™, Virbac Italy.

Table 4. Distribution of quarters by their infection status and treatment after calving.

Drying-off status^1	Outcome^2, %
	Negative	Cured	Cured/New IMI	NO cure	New IMI
Negative	64.6^a,3	–	–	–	35.4^b
IMI^4	–	35.0^a	33.5^a	31.5^a
Transient IMI	–	38.9^a	28.6^b	32.5^b

¹ Infection status defined as reported in Table S1 (Supplementary Data).

² Outcome defined as reported in Table S2 (Supplementary Data).

³ Column means with different letters are statistically different at χ² test (α < 0.05).

⁴ Intramammary infection.

Table 5. Distribution of quarters by their infection status and treatment after calving.

Drying-off status^1	Treatment	Outcome^2, %
		Negative	Cured	Cured/New IMI	NO cure	New IMI
Negative	No	69.7^a,3	–	–	–	28.3^a
	A^5	46.6^b				53.4^b
	B^6	62.0^a				38.0^a
IMI^4	No	–	32.6^a	34.2^a	33.2^a
	A^5	–	45.2^b	29.3^a	25.5^a
	B^6	–	28.7^a	36.2^a	35.1^a
Transient IMI	No	–	43.3^a	29.3^a	27.4^a
	A^5	–	28.8^b	34.7^a	36.5^a
	B^6	–	36.3^a,b	37.6^a	26.1^a

¹ Infection status defined as reported in Table S1 (Supplementary Data).

² Outcome defined as reported in Table S2 (Supplementary Data).

³ Row means with different letters are statistically different at χ² test (α < 0.05).

⁴ Intramammary infection.

⁵Treatment A: cefalonium 250 mg. Cepravin™, MSD Italy.

⁶Treatment B: cefalexin 504.7 mg Rilexine HL™, Virbac Italy.

Table 6. Logistic regression analysis: factors associated to the odds of a cure across the dry period.

Factor (p for overall effects)	Levels	p Value	OR	95% Lower limit	95% Upper limit
Parity (reference 1)	2	0.03	0.72	0.53	0.97
(p = .089)	≥3	0.36	0.85	0.59	1.21
Drying-off lenght	1–45	0.01	0.59	0.41	0.86
(reference 46–60 days)	61–75	0.21	0.81	0.58	1.13
(p = .027)	≥75	0.11	0.71	0.46	1.08
Teat sealant (reference = NO)	YES	<.01	3.12	2.35	4.19
Infection status (reference = transient IMI^1)	IMI	0.32	1.15	0.88	1.50
Therapy (reference = NO)	Product A^2	0.83	1.04	0.74	1.47
(p = .102)	Product B^3	0.07	0.74	0.54	1.02

¹ Intramammary infection.

² Product A: cefalonium 250 mg. Cepravin™, MSD Italy.

³ Product B: cefalexin 504.7 mg Rilexine HL™, Virbac Italy.

Table 7. Logistic regression analysis: factors associated to the odds of a new infection across the dry period.

Factor (p for overall effects)	Levels	p Value	OR	95% Lower limit	95% Upper limit
Parity (reference 1)	2	0.75	0.96	0.73	1.25
(<.01)	≥3	<0.01	0.49	0.34	0.72
Dry period lenght	1–45	<0.01	0.45	0.32	0.66
(reference 46–60 days)	61–75	0.27	0.85	0.64	1.13
(p < 0.01)	≥75	<0.01	0.24	0.16	0.38
Teat sealant (reference = NO)	YES	.02	0.72	0.55	0.94
Infection status (reference = Healthy)	transient IMI^1	<0.01	4.09	2.85	5.86
(p < .01)	IMI	<0.01	5.85	4.13	8.29
Therapy (reference = NO)	Product A^2	<0.01	1.95	1.40	2.70
(p < .01)	Product B^3	0.18	1.23	0.91	1.63

¹ Intramammary infection.

² Product A: cefalonium 250 mg. Cepravin™, MSD Italy.

³ Product B: cefalexin 504.7 mg Rilexine HL™, Virbac Italy.

Barkema HW, Schukken YH, Lam T, Galligan DT, Beiboer ML, Brand A. 1997. Estimation of interdependence among quarters of the bovine udder with subclinical mastitis and implications for analysis. J Dairy Sci. 80:1592–1599.

 PubMed Web of Science ®Google Scholar

Barry J, Brown A, Ensor V, Lakhani U, Petts D, Warren C, Winstanley T. 2003. Comparative evaluation of the VITEK 2 Advanced Expert System (AES) in five UK hospitals. J Antimicrob Chemother. 51:1191–1202.

 PubMed Web of Science ®Google Scholar

Church GT, Fox LK, Gaskins CT, Hancock DD, Gay JM. 2008. The Effect of a shortened dry period on intramammary infections during the subsequent lactation. J Dairy Sci. 91:4219–4225.

 PubMed Web of Science ®Google Scholar

Cameron M, Keefe GP, Roy JP, Stryhn H, Dohoo IR, McKenna SL. 2015. Evaluation of selective dry cow treatment following on-farm culture: milk yield and somatic cell count in the subsequent lactation. J Dairy Sci. 98:2427–2436.

 PubMed Web of Science ®Google Scholar