Facing fertility challenge in winter milk herds

It’s more costly to produce milk during the winter months. Unless the market can return a reasonable premium to the supplier, a liquid-winter milk bonus, you would have to question why should farmers produce it during the winter when feed is more expensive and hence margin to the farmer is smaller.

A certain volume is needed for fresh products consumed during the winter months but producing any more than what is required simply makes no sense and does not help farmer margins.

Over the last number of years, technologies associated with spring-calving farms have evolved, but some winter milk farmers believe there are different barometers to measure efficiency on a winter milk farm. The Irish Farmers Journal sat down with Joe Patton of Teagasc to discuss what targets and values should concern farmers producing milk during the winter.

Q&A

With Joe Patton

Q: Is calving interval a good measure of a herd for farmers producing winter milk?

A: Winter calving herds should target a 370-day calving interval. When calving interval increases, the gap between 305-day yield and actual milk yield widens. The net result is you sell less milk per cow per year and you also get fewer replacement heifer calves per year. Calving pattern loses structure and you increase herd health risks.

Q: Have you quantified the costs of a poor calving pattern on a winter milk herd?

A: We looked at this for a typical 100-cow herd. The extra feed cost of a spread-out calving pattern compared with a structured calving pattern is about €7,100 if the farmer has a contract to supply about 700 litres daily over winter months.

When I say spread-out calving pattern I mean something like what is in Table 2, where cows start calving in January and continue right through the year, with cows calving every month except the month of July.

The effects of the spread-out calving pattern and why they are less profitable is mainly because a farm will produce a lot more milk surplus to contract. That means not attaining a premium when supplied during winter months. Secondly, there are much higher feed costs, extra cow and young stock management and more cows at risk of recycling.

Q: Is 24-month-old calving necessary for winter milk producers?

A: I think it is absolutely necessary. If I was to compare two farms milking 130 cows with both having a 26% replacement rate, one farm calving down for the first time at 24 months and the other calving down at 30 months, our figures show there is a difference of about €10,200 in margin between the farms. Effectively the farm is carrying a higher stocking rate to carry the same number of cows. That’s the equivalent margin for 17 cows in the herd. This comes about from higher feed requirement and extra overheads for keeping heifers dry longer.

Q: But some farmers argue you get better performance when heifers calve at 30 months?

A: Yes, you might get slightly better first-lactation performance but lower subsequent and lifetime yield, increased days to conception and three times less likely to reach fourth lactation.

Q: Is breeding for fertility as important for winter milk herds?

A: Yes, I believe it is. Our data shows that EBI improves the traits needed for resilient cows that last in winter milk herds. Results from over 20,000 cows involved in winter milk shows high fertility EBI cows reach fourth lactation much quicker.

About 50% of fourth-lactation high-fertility cows reach that stage by 1,130 days compared with 1,470 days for low-fertility genetics. To put this another way, it means low-fertility cows take one year longer to reach fourth lactation. There is also a higher proportion of high fertility cows surviving to fourth lactation (64% versus 29%).

Q: But what difference does high-fertility EBI genetics make?

A: Essentially it means cows will have a similar peak milk solids but higher lifetime yield. Better body condition score on equal diets, less uterine infections, fewer silent heats and better quality embryos.

Q: So what type of performance should we be targeting for winter milk herds?

A: For me, the first calving needs to happen at 22 to 24 months of age. Calving interval must be less than 370 days. The aim must be to deliver greater than 85% of liveweight, which means 510kg of milk solids from 600kg cows. Milk protein must be 3.60% plus with 4,500 litres from forage, which is essentially 7,100 litres from 1.2t of concentrate. Lifetime yield must aim for 2.500kg of milk solids. The basics like somatic cell count less than 100 and sound feet and legs apply, of course.

Q: What bull selection guidelines would you advise?

A: Select a team of five to six bulls. EBI must be €260 with a fertility sub-index over €140, combined milk solids plus 20kg to 25kg and 40kg to 60kg of milk is adequate.

Q: A lot of farmers argue for much higher-volume sires – over 250kg of milk?

A: Yes, this is probably where we get most queries and the question is if 40kg to 60kg of milk volume is enough following the base change.

Our experience shows us that plus 40kg to 50kg of milk in sire proofs is more than enough to deliver a 7,500-litre herd average.

Q: What makes better fertility real or is it a paper figure only?

A: It comes back to all the issues that make up fertility performance; fewer calving problems, cows cycle sooner, uterine condition is better, there are fewer silent heats, higher progesterone after service, and less embryo mortality. All these fertility issues are essential in spring- or winter-calving herds. As the national herd has really pushed for higher fertility, less and less hormonal treatments are being used – higher fertility is washing out.