Feeding for fertility
The quality of feeding in the dry period and early lactation is important in achieving good herd fertility. The following need to be considered:
- Body Condition Score (BCS) at breeding should be 2.75 plus to improve conception rates. What if some cows are still well below target at start of breeding? It will take a couple of months to fix very thin milking cows by feeding 2-3kg extra meal. Short-term improvements in conception rate will be minimal. If there are thin or non-cycling cows in the herd that are due for breeding, milking once-a-day for 6 weeks can boost fertility
- High EBI cows have been proven to maintain better BCS across a range of diets, explaining in part why their fertility is better. Use high EBI bulls to make feeding simpler in the long term.
- Energy intake drives milk performance, maintains BCS, and improves fertility. Ensure that the herd is grazing the best quality grass possible (1400kg covers, 3 leaf stage). Watch residuals (target 4cm) to make sure cows are cleaning paddocks but not being pinched on intake. Supplement deficits in grass in good time.
- Protein in the diet- high quality pasture contains a high level of crude protein (Nitrogen) which milking cows use with feed energy to make milk protein. Surplus diet N may elevate blood and milk urea levels and this may give rise to concerns on fertility. Under good management, bulk milk urea does not explain much difference in fertility between herds. Apply fertilizer N small-and-often during the breeding season, do not overload fertilizer N under drought conditions, and feed high energy 14% crude protein rations at grass to control any risk.
- Trace minerals (Copper, Cobalt, Iodine, Selenium, Manganese and Zinc) can affect fertility if lacking in the diet. However, feeding these minerals above requirements is expensive and will not boost fertility where no deficiency exists. The ‘silver bullet’ of extra minerals will not fix the problems of thin cows, poor heat detection or bad genetics.
Body condition score cows
Body condition is critical to a successful breeding season. Identifying thin cows early allows steps to be taken to improve their body condition in good time. The first step is to body condition score all animals in the herd. The next step is to provide extra care and attention to thinner animals
Normally on farms the percentage of cows falling below the target body condition score of 2.75 prior to mating is less than 5% of the herd.
The first 2 cows in the cattle race 2294 and 2286 are below the target body condition score of 2.75 at mating. Both of these animals are second lactation animals producing 2.20kg of milk solids currently. These cows require extra care and attention in order to increase the condition score.
Increasing cow body condition score
The steps that should be taken with this group of cows can be any of the following or a combination of them:
- Once a day milking – cows come into the parlour twice a day for feeding but are only milked once. In larger herds these animals may be grouped together for preferential treatment, grazed closer to the milking parlour for less walking etc.
- Feed the cows fully with 24-36 hour allocations of grass with covers of 1,400 -1,500 kg dry matter per hectare of high DMD perennial ryegrass swards and supplement with concentrates where necessary to cover minerals etc. Do not use strip wires unless weather dictates otherwise.
- Top up the level of concentrates fed to the thinner cows. This in combination with once –a-day milking would result in an increase in cow body condition