Nutrition during Breeding Season

Delayed breeding has a relative cost per day and increases as the calving to conception interval lengthens. By maintaining or reducing the calving to conception interval, there is an opportunity to save or gain over €20,000 on a 100-cow herd due to increased days in milk, increased longevity within the herd and reduced repeat costs.

Achieving high fertility performance requires a multifaceted approach including good nutrition management, health management and genetics focusing on high EBI bulls with a high fertility sub-index and good heat detection.

Pre-breeding Management

Body condition management is key when preparing the cow for the approaching breeding season. Poor quality silage, tight silage stocks and on/off grazing for prolonged periods may have caused a greater duration of Body Condition Score (BCS) loss. Body condition should be assessed with the ideal being  3-3.25 of a BCS. Cows currently in the correct BCS must be maintained and those behind target need to be fed a higher plane of nutrition leading into and during the breeding season to gain body condition to maximise submission and conception rates.

For every 0.25 of a BCS to be gained requires 50 UFL (energy unit). To gain 0.25 over the next 4 weeks requires an extra 2 kg of concentrates on top of supplementation for maintenance and milk production. When transitioning to full-time grazing it is vital to reduce supplementation slowly to ensure cows are not restricted, dry matter intakes are maintained and cows are allowed to adjust to grazing again.

Feeding now for BCS gain, BCS maintenance or to push heifers closer to their target weight heading into and during the breeding season is a relatively short-term investment into the next lactation and next year’s milk production.

Trace minerals such as Copper, Iodine, Selenium and Zinc can affect fertility if lacking in the diet. If fertility performance is suboptimal despite cows being in good condition, good heat detection and vaccination protocols, it may be worth taking blood samples to identify any possible mineral deficiencies.

Commence pre-breeding 3 weeks before the breeding start date. Implement a simple form of heat monitoring (e.g., tail paint with twice weekly checks) to identify non-cycling cows, allowing rectifying issues without prolonging the breeding season.

During the Breeding Season

Energy intake drives milk performance, maintains BCS, and improves fertility. Ensure that the herd is grazing the high-quality grass. Pre-grazing covers 1200-1400 kg DM (2.5-3 leaf stage) and maximises intakes, utilisation and thus energy intake. Watch residuals (target 4cm) to make sure cows are cleaning paddocks but not being pinched on intake. Supplement deficits in grass in good time by monitoring grass growth and the weather forecast. If rain is forecasted increase supplementation by 1.5 – 2 kg to maintain dry matter and energy intakes.

High-quality grass can contain high levels of crude protein (Nitrogen) which cows use with feed energy to make milk protein. Surplus dietary N may elevate blood and milk urea levels and this may give rise to concerns about fertility. Apply fertilizer N small and often during the breeding season to reduce significant fluctuations in milk ureas. Feed high energy low crude protein rations at grass to control any risk.

GAIN Spring Breeder

GAIN Spring Breeder is a 13% protein nut that supports milk solids and fertility as it is high in energy and digestible fibre but low in crude protein. It contains three critical components; Novantan, Bioplex protected mineral and Selplex. Novatan is a Rumen modifier, which improves protein utilisation by reducing protein breakdown in the rumen and increasing by-pass protein into the small intestine to be used for milk and milk protein production. This reduces urea in blood and milk, improving the uterine environment and subsequently improving conception rates. Novatan has been shown to increase milk yield by 1.5-2.5 litres/day and milk protein by 0.1-0.2%.

Minerals and Trace Elements

Trace minerals such as Selenium play a key role in maintaining a healthy immune system, needed for a healthy womb which is critical for optimal fertility. Other trace minerals such as Copper and major minerals such as Phosphorus, play key roles in ovulation or cycling, if there is a deficiency of either then anoestrus is a real possibility. Common mineral deficiencies prevalent in Ireland are Phosphorus, Copper, Selenium, Iodine and Zinc. Cows should be supplemented with minerals at the appropriate rate to complement the minerals supplied in the grazed grass.

Bioplex copper supports fertility, Bioplex Zinc supports hoof and udder health, while Selplex Selenium improves somatic cell count (SCC), mastitis and fertility.

Organic minerals are more available to the animal than in their inorganic form. Organic Selenium is 4 times more available with organic zinc being 2.25 times more available than in its inorganic form. The use of organic (Bioplex) minerals have been shown to be worth €5,500 per annum in a 100 cow herd (Somatic Cell Count, Lameness, Conception rates and Mastitis), used in GAIN Spring Breeder 13%.

A compact calving pattern, correct BCS, adequate minerals and total dietary energy intake are factors that contribute to achieving milk solids targets such as those outlined in the milk solids tracker within the GAIN Momentum Programme.

First Published 2 May 2024