Problems associated with clinical/subclinical disease:
Increased Clinical Disease Risk
Impaired immune function
Increased risk of culing
TRANSITION COW MANAGMENT
It is at this stage we need to take time to check and work towards reducing the incidence of clinical and subclinical disease within the herd as these will have a negative effect on production and fertility.
Diseases are divided into clinical such as mastitis, lameness, milk fever, retained placenta, or displaced abomasum, but there are also subclinical diseases which can be more difficult to identify.
The duration of these diseases can be quite short, but the effects may persist through the entire lactation, and the incidence of these diseases can have a profound effect on the number of days it takes to get cows pregnant.
Effects of disease on fertility:
Prolong the time cows spend in lower-producing stages of lactation, by reducing the number of offspring for replacements or for sale,
Increase the likelihood the animal will be culled prematurely
Reproductive failure and mastitis are consistently recorded as the top two reasons for culling.
On most farms a proportion of cows will be anoestrours (i.e. not displaying behavioural heat) at the start of the breeding period. Most cows should display behavioural heat 38 - 47 days post calving, failure to show signs of heat by 60 days after calving is called postpartum anoestrus which can be due to true anoestrus or subestrus.
HerdInsights automatically generates a list of cows pre breeding that are not cycling relative to their calving date.
This list can be easy accessed on your mobile phone and can be forwarded to your vet or scanner for attention. All cows that are not seen in heat by day 42 should be examined by the vet. It is these problem cows that your vet should be putting the effort into in order to get them into oestrus as soon as possible cows that will give a return on investment of vet fees.
Not identifying your non-cycling cows results in a calving to pregnancy interval approaching 400 days, with replacement rates of 20-30% needed to maintain a 14-week calving period for grass-based milk production systems.
A cow calving in May will generate €400 less profit than a cow calving in February, due to higher feed costs and reduced yield (Teagasc). As such increasing submission rates on cows that are eligible to be bred will maximise profits.
Additionally, HerdInsights highlights the calving to first heat period. This duration will help management in assessing nutrition, BCS, genetics and management practices and can be used as a decision aid when evaluating transition cow management practices.
True Anoestrus is when cows have inactive ovaries
Causes of anoesturs:
Poor body conditioning at calving - in a dairy cow that is thin at calving, ovulation of the first dominant follicle will only occur in 20% of cases.
A large energy deficit in early lactation - a significant energy deficit in the weeks following calving delays the first ovulation.
Inappropriate feeding after calving
Poor heat detection
Suckling - The stimulus of suckling, sometimes linked to a poor body condition, lowers the frequency of LH pulses. Therefore, only 25 to 30% of suckling cows ovulate their first post-partumdominant follicle.
Is when cows have normal cyclical ovarian activity but are not detected in heat due to weak or silent heat.
90% of dairy cows in which heat has not been observed in the 60 days after calving the cow will have evidences of cyclical activity on the ovaries.
Suboestrus is the most frequent cause of infertility in high producing dairy herds.
Main causes of suboesturs:
Poor observation of heat
High milk production
Restriction of oestrus activity - hard or slippery footing limits the physical activity and in particular the incidence of mounting behaviour.
Cystic ovarian disease (COD) in cows is usually seen in the first two months post calving. Major categories of cysts include follicular cysts, luteinized follicular cysts and cystic corpora lutea.
Abnormal estrous behavior patterns are the most noticeable sign of cystic ovarian disease.
This includes persistent oestrus, shortened oestrus intervals or failure to cycle (anoestrus). Anoestrus is by far the most common sign.
Behavioral aberrations range from frequent, intermittent estrus with exaggerated monosexual drive to bull-like behavior, including mounting. This persistent bulling behaviour, or nymphomania, is by far the least common clinical sign associated with cystic ovaries.
Typically, 5 – 10% of cows are affected with COD per year Hooijer et al., 2001), but the incidence may be up to 30% in older animals.
COD results in economic losses associated with extended calving interval or days open, an increase in empty rates and treatment costs. The extreme, but by no means uncommon cost, being associated with culling the cow and having to use replacements that may otherwise have been sold!
Treatment of COD in cattle addresses the underlying factors responsible for the development of the condition.
Correction of nutritional and metabolic disorders
Hormonal treatment leading to resumption of cyclic ovarian activity