title: Multiple correlation analyses of metabolic and endocrine profiles with fertility in primiparous and multiparous cows.
abstract: Results from 4 studies were combined (representing a total of 500 lactations) to investigate the relationships between metabolic parameters and fertility in dairy cows. Information was collected on blood metabolic traits and body condition score at 1 to 2 wk prepartum and at 2, 4, and 7 wk postpartum. Fertility traits were days to commencement of luteal activity, days to first service, days to conception, and failure to conceive. Primiparous and multiparous cows were considered separately. Initial linear regression analyses were used to determine relationships among fertility, metabolic, and endocrine traits at each time point. All metabolic and endocrine traits significantly related to fertility were included in stepwise multiple regression analyses alone (model 1), including peak milk yield and interval to commencement of luteal activity (model 2), and with the further addition of dietary group (model 3). In multiparous cows, extended calving to conception intervals were associated prepartum with greater concentrations of leptin and lesser concentrations of nonesterified fatty acids and urea, and postpartum with reduced insulin-like growth factor-I at 2 wk, greater urea at 7 wk, and greater peak milk yield. In primiparous cows, extended calving to conception intervals were associated with more body condition and more urea prepartum, elevated urea postpartum, and more body condition loss by 7 wk. In conclusion, some metabolic measurements were associated with poorer fertility outcomes. Relationships between fertility and metabolic and endocrine traits varied both according to the lactation number of the cow and with the time relative to calving.
authors.affiliation: Reproduction, Genes and Development Group, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Herts AL9 7TA, UK. dcwathes@rvc.ac.uk
authors.forename: D C
authors.initials: DC
authors.lastname: Wathes
authors.forename: N
authors.initials: N
authors.lastname: Bourne
authors.forename: Z
authors.initials: Z
authors.lastname: Cheng
authors.forename: G E
authors.initials: GE
authors.lastname: Mann
authors.forename: V J
authors.initials: VJ
authors.lastname: Taylor
authors.forename: M P
authors.initials: MP
authors.lastname: Coffey
mesh_terms: D000818:Animals; D001824:Body Constitution / Q000502:physiology; D002417:Cattle / Q000378:metabolism / Q000502:physiology*; D003338:Corpus Luteum / Q000502:physiology; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D005298:Fertility / Q000502:physiology*; D005306:Fertilization / Q000502:physiology; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D007774:Lactation / Q000502:physiology; D016018:Least-Squares Analysis; D020738:Leptin / Q000097:blood; D008892:Milk / Q000378:metabolism; D010298:Parity / Q000502:physiology*; D011247:Pregnancy; D013223:Statistics as Topic; D013997:Time Factors
chemical_list: D005230:Fatty Acids, Nonesterified; D020738:Leptin; D007334:Insulin-Like Growth Factor I