What Stops Cow Reproduction Being Successful?
Those scratching their heads over reaching reproductive targets may want to consider six factors, say a team of Irish researchers.
12 August 2014
2 minute read
In the Journal of Dairy Science, the team, made up of three University College Dublin and one Teagasc expert, states that reproduction may hinge on:
- Increased metabolic activity of the liver (increased glutamate dehydrogenase at calving and increased γ-glutamyl transpeptidase in week four postpartum)
- A competent immune system (increased neutrophils in week one postpartum; decreased α1-acid glycoprotein in weeks one, two and three postpartum)
- An endocrine system that was capable of responding by producing sufficient triiodothyronine in week two postpartum, and increased insulin-like growth factor I in weeks three and four postpartum
- A lower negative energy balance status (decreased nonesterified fatty acid concentration in week one postpartum; decreased β-hydroxybutyrate concentration in week two postpartum; body condition score (BCS) loss between calving and day 28 postpartum less than 0.5)
- Good reproductive tract health (normal uterine scan at day 45 postpartum; clear vaginal mucus discharge at first ovulation and at day 45 postpartum; resumed ovarian cyclicity by the end of the voluntary waiting period)
- Adequate diet (to ensure increased glutathione peroxidase in week two and three postpartum and increased magnesium in week four). Furthermore, the risk factors that increased the odds of a successful first artificial insemination (A.I.) were previous ovulation(s) (odds ratio = 3.17 per ovulation), BCS >2.5 at A.I. (odds ratio = 3.01) and clear vaginal mucus (score = 0) compared with purulent mucus (score >0) 4 days after first A.I. (odds ratio = 2.99).
