Spring calving programmes are now on week eight on most farms, with close to 80pc of cows calved. Late calvers are still to be calved in the next two months. The weather has been excellent for grass growth with early turnout by day and night on farms in the south.
High rainfall has meant poor ground conditions for grazing on heavy, impermeable soils. Cows are still indoors on dairy farms across Northern Ireland.
The system of milk production is radically different to that in the South. There is a greater focus on autumn calving. Many farmers there associate a turnout to grass with a decrease in pregnancy rates.
The quality of eggs for fertilisation after AI is dependent on an egg cycle beginning six to eight weeks earlier. Therefore, the management of your cows now will dictate the heat detection and pregnancy rate of cows to first AI from April 20 onwards.
Events such as milk fever, retained afterbirth, lameness, excessive body condition score (BCS) and mastitis will impact negatively on the egg selection process. It is important to place a focus not alone on milk quality and quantity from grazed grass but also the requirements for the reproductive performance of your herd.
The primary focus in your herd now has to be the future reproductive potential being met by supplementation of grazed grass with nutrients to enhance egg quality during the six-week pre-breeding period.
Cows calving from eight weeks onward in the calving programme are late calvers. These cows are faced with the highest risk of reproductive failure in the spring breeding programme. Emphasis on dry cow management here will pay dividends in the future. These cows are not allowed access to grass on many farms. Poor quality silages with poor pit face management are a recipe for poor reproductive performance.
Focus on your remaining dry cows to ensure they calve down with minimal health issues and achieve a complete uterine involution by three weeks after calving. Avoid losses in body condition and feed the necessary dry cow minerals.
Are your maiden heifers achieving the desired target weights for breeding? This will depend on the genetic makeup of the heifers. Are your heifers cycling now? If not, the heifers have been exposed to an underlying stressor or are too young to be bred in six weeks time.
Overcrowding of heifers in pens, poor quality silages, coccidiosis and cryptosporidium as calves will delay the onset of puberty. Heifers not cycling and those not reaching the target weights will benefit from supplementation with 3kg of ration designed for growing heifers while on grazed grass.
Are your vaccination programmes up to date? Booster injections for vaccination against leptospirosis and BVD should be in place now. Vaccination against IBR requires two boosters annually at six-month intervals. In my opinion, IBR is the greatest cause of concern in terms of reproductive health in the dairy herd.
The levels of antibodies generated in response to vaccination will be poor if cows are stressed. Ensure liver fluke, stomach fluke, lice, mange, excessive BCS loss and lameness are not issues in your herd. These stressors will depress the immune systems resulting in a poor defence mechanism to disease.
The success of an AI breeding programme is dependent on high detection rates.
Plan now for a heat detection rate in excess of 90pc. Unfortunately, figures closer to 60pc are the norm on Irish grass-based dairy farms.
Aim to identify those cows not cycling which are greater than 40 days calved at the onset of the breeding season. Tail painting, teaser bulls with chin-ball markers and MooMonitors are excellent aids in heat detection. Put one of these aids in place now and it will help identify underlying herd health problems.
• Focus on a management programme that will deliver on egg quality for AI in four to six weeks time.
• Late calvers kept indoors need excellent silage with a mineral supplement.
• Maiden heifers must achieve target weights to avoid being non-cycling heifers.
• Vaccination and health management programmes need to be kept up to date.
Dr Dan Ryan is a breeding management consultant at www.cows365.ie