Vasectomised bulls: Time is running out to get bulls vasectomised. There should be at least six weeks between the operation and when the bull is introduced to female animals. He’ll be producing viable ejaculates for a few weeks after the operation. The trick with teasers is to not let them in too early and give them too much work to do. If you do they’ll be worn out and will start missing cows. Only use him after the first four or five weeks, when bulling activity tails off. Larger herds should have a number of bulls and rotate them to prevent them from being over worked. One teaser bull to 30 or 40 not in-calf cows is probably OK, but the ratio should halve for young bulls. With fertility in the national herd improving, it’s taking less dairy AI straws to get a heifer in the parlour milking. Before, it used to take five dairy straws, now it’s only taking four dairy AI straws.

Butterfat: Orla Neville is a PhD student working with Finbar Mulligan in UCD on ways to reduce butterfat drop in dairy cows. This is her advice on how to prevent butterfat dropping over the next few weeks: The main cause of milk fat depression at grass is the ingestion of high quantities of polyunsaturated fatty acids (PUFA) where rumen pH is low. Scientifically proven intervention strategies to reverse or prevent milk fat depression are scarce. The following strategies should be considered; avoid high oil grass, which is also low (<35%) in neutral detergent fibre (NDF), this might be achieved by avoiding going into very low covers (less than 1,200kg/ha). This type of grass is high in oil and low in NDF. If milk fat has recently crashed, try lifting the pre-grazing cover by 200kg/ha, such as going from 1,400kgDM/ha to 1,600kgDM/ha. Both of these measures require grass growth to be good. Strip-grazing using a 12-hour wire will force the cow to eat stem and leaf. For the second rotation, consider following the cows with fertiliser instead of blanket spreading fertiliser, as grass that is high in nitrogen is also high in oil. If you’re feeding a lot of meal, avoid wheat (it drops rumen pH) and avoid high inclusion of maize distillers (as there is a high oil content). Feeding un-molassed beet pulp, soya hulls and nutritionally-improved straw is considered good for rumen pH. The use of mineral buffers reduces durations of low rumen pH and increases fat yield in grazing cows, rumen pH and milk fat percentage have been improved in indoor diet types. Use of live yeast, has been shown to reduce periods of low rumen pH. The yeast effect was the same, regardless of whether cows were fed TMR or grazing. Full TMR diets may increase rumen pH in comparison to grass based diets. The benefits of partial TMR for fat yield later in the grazing season are proven (mainly driven by yield). Although it would seem the right thing to do, some southern hemisphere research would indicate little benefit on rumen pH from feeding straw to grazing cows. Protected C16 fat supplements have shown significant improvement in fat yield in grazing cows (albeit in mid to late lactation). Finally, cow genetics, high fat percentage PTA and high fat kg PTA cows, are less likely to have an issue with milk fat depression.