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Subclinical ketosis in post-partum dairy cows fed a predominantly pasture-based diet: defining cut-points for diagnosis using concentrations of beta-hydroxybutyrate in blood and determining prevalence.
N Z Vet J. 2015 Sep; 63(5):241-8.NZ

Abstract

AIMS

Firstly, to define, in dairy cows in the first 5 weeks post-calving fed a predominantly pasture-based diet, cut-points of concentrations of beta-hydroxybutyrate (BHBA) in blood, above which there were associations with purulent vaginal discharge (PVD), reduced pregnancy rates (PR) and decreased milk production, in order to better define subclinical ketosis (SCK) in such cattle; and secondly, to determine the prevalence, incidence and risk factors for SCK.

METHODS

An observational field study was conducted in 565 cows from 15 spring-calving and predominantly pasture-fed dairy herds in two regions of New Zealand during the 2010- 2011 dairy season. Within each herd, a cohort of randomly selected cows (approximately 40 per herd) was blood sampled to determine concentrations of BHBA on six occasions at weekly intervals starting within 5 days of calving. The key outcome variables were the presence/absence of PVD at 5 weeks post-calving, PR after 6 weeks (6-week PR) and after the completion of the breeding season (final PR), and mean daily milk solids production.

RESULTS

Two cut-points for defining SCK were identified: firstly concentration of BHBA in blood≥1.2 mmol/L within 5 days post-calving, which was associated with an increased diagnosis of PVD (24 vs. 8%); and secondly concentration of BHBA in blood≥1.2 mmol/L at any stage within 5 weeks post-calving, which was associated with decreased 6-week PR (78 vs. 85%). The mean herd-level incidence of SCK within 5 weeks post-calving was 68 (min 12; max 100)% and large variations existed between herds in peak prevalence of SCK and the interval post-calving at which such peaks occurred. Cows>8 years of age and cows losing body condition were at increased risk of SCK within 5 weeks of calving.

CONCLUSIONS

Cows with concentration of BHBA in blood≥1.2 mmol/L in early lactation had a higher risk of PVD and lower 6-week PR. Cow and herd-level prevalence of SCK varied widely in early lactation.

CLINICAL RELEVANCE

Subclinical ketosis is common and is significantly associated with reproductive performance in mainly pasture-fed New Zealand dairy cattle. Controlling SCK may therefore result in improvements in herd reproductive performance. However considerable variation exists among herds in the incidence of SCK and in the timing of peak prevalence which means that herd-specific monitoring programmes are required to define herd SCK status accurately.

Authors+Show Affiliations

a Cognosco , Anexa Animal Health , PO Box 21, Morrinsville , New Zealand.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

25578216

Citation

Compton, C W R., et al. "Subclinical Ketosis in Post-partum Dairy Cows Fed a Predominantly Pasture-based Diet: Defining Cut-points for Diagnosis Using Concentrations of Beta-hydroxybutyrate in Blood and Determining Prevalence." New Zealand Veterinary Journal, vol. 63, no. 5, 2015, pp. 241-8.
Compton CW, Young L, McDougall S. Subclinical ketosis in post-partum dairy cows fed a predominantly pasture-based diet: defining cut-points for diagnosis using concentrations of beta-hydroxybutyrate in blood and determining prevalence. N Z Vet J. 2015;63(5):241-8.
Compton, C. W., Young, L., & McDougall, S. (2015). Subclinical ketosis in post-partum dairy cows fed a predominantly pasture-based diet: defining cut-points for diagnosis using concentrations of beta-hydroxybutyrate in blood and determining prevalence. New Zealand Veterinary Journal, 63(5), 241-8. https://doi.org/10.1080/00480169.2014.999841
Compton CW, Young L, McDougall S. Subclinical Ketosis in Post-partum Dairy Cows Fed a Predominantly Pasture-based Diet: Defining Cut-points for Diagnosis Using Concentrations of Beta-hydroxybutyrate in Blood and Determining Prevalence. N Z Vet J. 2015;63(5):241-8. PubMed PMID: 25578216.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Subclinical ketosis in post-partum dairy cows fed a predominantly pasture-based diet: defining cut-points for diagnosis using concentrations of beta-hydroxybutyrate in blood and determining prevalence. AU - Compton,C W R, AU - Young,L, AU - McDougall,S, Y1 - 2015/06/15/ PY - 2015/1/13/entrez PY - 2015/1/13/pubmed PY - 2015/9/26/medline KW - Subclinical ketosis KW - beta hydroxybutyrate KW - pasture-grazed dairy cattle KW - pregnancy rate KW - purulent vaginal discharge SP - 241 EP - 8 JF - New Zealand veterinary journal JO - N Z Vet J VL - 63 IS - 5 N2 - AIMS: Firstly, to define, in dairy cows in the first 5 weeks post-calving fed a predominantly pasture-based diet, cut-points of concentrations of beta-hydroxybutyrate (BHBA) in blood, above which there were associations with purulent vaginal discharge (PVD), reduced pregnancy rates (PR) and decreased milk production, in order to better define subclinical ketosis (SCK) in such cattle; and secondly, to determine the prevalence, incidence and risk factors for SCK. METHODS: An observational field study was conducted in 565 cows from 15 spring-calving and predominantly pasture-fed dairy herds in two regions of New Zealand during the 2010- 2011 dairy season. Within each herd, a cohort of randomly selected cows (approximately 40 per herd) was blood sampled to determine concentrations of BHBA on six occasions at weekly intervals starting within 5 days of calving. The key outcome variables were the presence/absence of PVD at 5 weeks post-calving, PR after 6 weeks (6-week PR) and after the completion of the breeding season (final PR), and mean daily milk solids production. RESULTS: Two cut-points for defining SCK were identified: firstly concentration of BHBA in blood≥1.2 mmol/L within 5 days post-calving, which was associated with an increased diagnosis of PVD (24 vs. 8%); and secondly concentration of BHBA in blood≥1.2 mmol/L at any stage within 5 weeks post-calving, which was associated with decreased 6-week PR (78 vs. 85%). The mean herd-level incidence of SCK within 5 weeks post-calving was 68 (min 12; max 100)% and large variations existed between herds in peak prevalence of SCK and the interval post-calving at which such peaks occurred. Cows>8 years of age and cows losing body condition were at increased risk of SCK within 5 weeks of calving. CONCLUSIONS: Cows with concentration of BHBA in blood≥1.2 mmol/L in early lactation had a higher risk of PVD and lower 6-week PR. Cow and herd-level prevalence of SCK varied widely in early lactation. CLINICAL RELEVANCE: Subclinical ketosis is common and is significantly associated with reproductive performance in mainly pasture-fed New Zealand dairy cattle. Controlling SCK may therefore result in improvements in herd reproductive performance. However considerable variation exists among herds in the incidence of SCK and in the timing of peak prevalence which means that herd-specific monitoring programmes are required to define herd SCK status accurately. SN - 0048-0169 UR - https://www.unboundmedicine.com/medline/citation/25578216/Subclinical_ketosis_in_post_partum_dairy_cows_fed_a_predominantly_pasture_based_diet:_defining_cut_points_for_diagnosis_using_concentrations_of_beta_hydroxybutyrate_in_blood_and_determining_prevalence_ L2 - http://www.tandfonline.com/doi/full/10.1080/00480169.2014.999841 DB - PRIME DP - Unbound Medicine ER -