Precision Farming»Don’t esti­mate – measure and weigh«

It’s a mild spring day in south-west Germany with blossom and new leaves on the trees. Nobody would guess that in this fairly remote side valley, near the French border, a 200-cow dairy farm oper­ates, with its herd producing an average annual milk yield of almost 11,500kg per cow – well above the region’s 9,125kg/cow average.

Inse-Marie Stalter and her husband, Fried­helm Meyer zur Capellen, run the Wahlerhof farm and herd with their niece, Sabrina, and her husband, Tobias Zarth, as well as two appren­tices, one full-time and three part-time employees.

Orig­i­nally constructed in the 1980s, the cow shed was rebuilt in 2015 in accor­dance with animal welfare guide­lines and expanded to have capacity for 200 cows. Orig­i­nating from northern Germany, Fried­helm and Tobias are more accus­tomed to achieving an average milk yield over 11,000kg – performing at the top farm level. The change in loca­tion, coupled with an appetite to exper­i­ment and share learn­ings, means the couples were well placed to become a partic­i­pating farm in the govern­ment-backed initia­tive, the More Sustain­able Milk project.

In this project, methods are devel­oped for producing milk more effi­ciently and more sustain­ably. Partic­i­pating farms include the Wahlerhof, Schmiedhof, Lehr-und Versuch­sanstalt Hofgut Neumühle and they are joined by the univer­sity RPTU Kaiser­slautern, the Hochwald Foods dairy, John Deere, and BASF SE, who are all part­ners in the project group.

A basic prereq­ui­site for the initia­tive is to gain the most accu­rate and complete data collec­tion and transfer across all stages of milk produc­tion. “Don’t esti­mate – measure and weigh,” is a saying that Inse-Marie hears again and again at project meet­ings, and which has now since become second nature to the entire Wahlerhof team.

Fertil­i­sa­tion with liquid manure and mineral fertiliser

The Wahlerhof comprises a total of 200ha, divided into 80ha of perma­nent grass­land, 20ha of rota­tional grass­land, 40ha of maize and 60ha of cash crops. Due to the weath­ered, shallow lime­stone soils, it is diffi­cult to achieve maximum yields from forage grown on site. To maximise forage produc­tion and quality, both liquid manure and mineral fertiliser are included in the farm’s nutrient strategy.

Currently, the nutrient content of the liquid manure is deter­mined using an NIR sensor when the slurry tanker is filled. Control samples are sent to the labo­ra­tory for vali­da­tion of the measure­ments. Nitri­fi­ca­tion inhibitors are used on the maize to utilise the nitrogen from the liquid manure as effi­ciently as possible during early appli­ca­tions. This year, the project plans to use soil samples and yield maps to create as-applied maps, along­side the use of NIR senses during manure appli­ca­tion, which will enable even more precise distri­b­u­tion.

Basic Feed Produc­tion

The produc­tion of high-quality, well-fermented and tasty grass silage is of the utmost impor­tance to Fried­helm and Tobias. “The harvest starts by deter­mining the optimum time to cut, with fresh grass and fresh maize samples taken to help deter­mine this,” says Fried­helm.

When harvesting grass silage, the entire field is mowed in one day with the support of a contractor. The cutting height is set to 8-10cm to avoid cont­a­m­i­na­tion of the silage and to favour grass regrowth for the next cut.

Silage addi­tives are used to improve effi­ciency of the ensiling process, as well as to improve storage. During both grass and maize harvesting, the yield and constituents are contin­u­ously measured using an NIR sensor. Samples are also sent to the labo­ra­tory to check sensor accu­racy.

This data provides valu­able infor­ma­tion for deci­sion-making around crop manage­ment, including fertiliser appli­ca­tions and reseeding. In addi­tion, the dry matter content of the harvested crop is used to deter­mine the optimum chop length, which is then adjusted accord­ingly on the machine.

Ration Calcu­la­tion And Feeding

As the nutrient contents are measured during harvest using the NIR sensor, Inse-Marie, Fried­helm and Tobias know fairly accu­rately how much feed, and of what quality, they have stored in their silos. Never­the­less, there are losses that need to be taken into account. These are fed in to a nutrient util­i­sa­tion analysis and to deter­mine green­house gas emis­sions (CO_2e); namely CO₂, methane and nitrous oxide.

The family aim for a grass silage dry matter (DM) content of 35-38%, which in the total mixed ration (TMR) ensures a uniform DM intake, less selec­tive feeding by cows and, there­fore, the optimum feed composition.This ensures an effi­cient, high feed intake, resulting in reduced CO_2e output per cow. To compen­sate for fluc­tu­a­tions in the mois­ture content of the basic feed, the DM content of the indi­vidual feed­stuffs is measured weekly using a portable NIR sensor, and the recipe for the ration is adjusted accord­ingly.

The TMR currently comprises a mix of silages; grass, corn, lucerne, and clover, as well as dried pulp, brewer’s grains and compen­satory feed. The dried pulp and brewer’s grains come from a sugar factory and a brewery in the neigh­bour­hood.

As many by-prod­ucts as possible are also used in the compen­satory feed in order to keep trans­port routes short for climate reasons, and to utilise as many prod­ucts as possible that would other­wise remain unused.

The total emis­sions from milk produc­tion at Wahlerhof were calcu­lated using the Cool Farm Tool and amount to 1.17kg CO₂ equiv­a­lent per kg FPCM (fat and protein-corrected milk) – the Wahlerhof ’s very high milk yield contributing to this figure.

Thanks to their partic­i­pa­tion in the More Sustain­able Milk project, Inse-Marie Stalter and her team already know that they produce milk with a compar­a­tively low CO_2e foot­print. But there’s still a lot to learn and opti­mise and she is keen to calcu­late the feed effi­ciency and Income Over Feed Cost (IOFC).

“By measuring the yields and ingre­di­ents during harvest, we know what is in the pile,” says Fried­helm. Tobias adds: “As feed manage­ment soft­ware is now also used, we can also calcu­late the conser­va­tion and storage losses.”