Winter grazing is an opportunity to seize it

DrThe researchers are Lucie Morin from the La Blanche Maison experimental farm (Manche), Julien Fortin from the Thorigné-d’Anjou experimental farm (Maine-et-Loire) and Tom Dupré from the Trévarez experimental farm (Finistère). The results are preliminary and have not yet been confirmed by repeated observations.

Grass also grows in winter

“We started from results that are repeated every year,” says Tom Dupret. “We have the ability to monitor the growth dynamics of rangelands throughout the year. We notice that the grass germinates early and early in the winter, in terms of quality and quantity, and that the growth does not stop in the winter. There was a growth rate of 10 kg of grass per hectare per day in 3 locations. The question arises whether you, as a cattle farmer, should use this source of nutrition and what new benefits may be associated with it. “

However, there are a number of limitations to winter grazing: in many cases there is a lot of water in the pastures. The absorptive capacity of the soil, which is related to the presence of abundant water, is also a limitation, as is the lack of knowledge of the amount of grass in the winter period and the nutritional value that can be attributed to it.

which animals?

“Based on these findings, we began working with grazing techniques, with differences in animal type and density (the number of animals in the pasture) and began to study the impact on damage to grasslands.” Then they began to look at the potential of wintergrass.

While researching the animals, the researchers measured the number of days on which winter grazing was possible and how much dry matter the animals could eat on the winter pastures.

Holstein

At Trivarez, the pastures were occupied alternately by 12 pregnant Holstein calves aged 19 months and 5 pregnant crossbreed calves aged 20 months. The average number of days on pasture ranged from 10 days for conventional dairy cows to 15 days for organic dairy cows. Ordinary cows went to graze alternately for 3 months (from the beginning of November to the end of January) compared to 2 months for the organic cows (from the beginning of December to the end of January). The initial meadow height was 9 and 8.2 cm, respectively. In terms of pasture occupancy, the annual average was 0.3 L/ha, and for classic cattle it was 2.85 L/ha in winter grazing. For organic milk cows, the annual mean was 0.85 L/ha or 2.85 L/ha for winter grazing. The grassland was planted with perennial ryegrass and white clover.

Limousine

At Thorigné-d’Anjou, the research was carried out on Limousin cows, heifers and calves (Limousin/Angus) aged 12 to 24 months. Winter grazing here was compared to cattle that did not graze in winter. During December and January, the average grazing was 0.5 LU/ha and 7 LU/ha, respectively, with field changes every 5 days. The grass height was initially 7.6 cm, which is relatively low. The meadow was sown with grass, perennial ryegrass, white clover, hybrid clover, and clover leaves.

Norman cattle

At La Blanche Maison, fifteen Norman cattle were followed from 12 to 24 months old. They remained on the pastures from the beginning of November until the middle of February, according to two types of pastures: free pastures and rotating pastures. So part of the cattle remained on the same plot of land all the time (low grazing in the winter months), while another part walked in designated areas of 0.5 ha (with 8 LU/ha) with plot rotation every 5 days. The grass height at the start was almost the same in the two conditions, 10 and 11.5 cm, respectively. The meadow consisted of both permanent and temporary grassland with perennial ryegrass, fescue, white, purple and mixed clover.

With these results in mind, the last winter in this part of France was very favorable for this first experience of winter grazing, with an average of 30% lower than normal, mild temperatures favoring grass and generally favorable conditions for the carrying capacity of the soil.

Results in Trevarez and Thorigné-d’Anjou

In 89 days of grazing for conventional cattle, approximately 10.5 tons of dry matter from the grass were absorbed by the calves, or 0.47 tons of dry matter per hectare. There was no supplementary feeding here. The calves were outside 24 hours a day. The average intake was 9.1 kg dry matter per animal per day.

On 62 days of grazing with organic cows, 2 tons of grass dry matter, or 0.52 tons of dry matter per hectare, were processed. The average intake was 7.2 kg dry matter per animal per day.

In Thorigné-d’Anjou, the intake over 55 days of grazing was 10.5 tonnes dry matter, or 0.42 tonnes dry matter per hectare. The average intake was 7.9 kg dry matter per animal per day (78% pasture grass, 22% hay with supplemental forage).

Results at La Blanche Maison

In 78 days of free grazing, 4.8 tonnes of dry matter was taken from the grass, or 1.1 tonnes of dry matter per hectare. The average intake was 8.8 kg dry matter per day for each animal. In 78 days of rotational grazing, 5.4 t dry matter or 1.25 t dry matter per hectare were taken. The average intake here was 8.6 kg dry matter per animal per day. Therefore, there is no difference in registration according to the two options.

Are there negative effects on grass growth in the spring?

On the three plots studied in Thorigné-d’Anjou, the yield of plots with winter grazing was compared with that of the plot without walking animals that winter. The yield of the last plot was 2 tons of dry matter. On pastures with winter grazing, the yield was just over 1 ton of dry matter. If you add to this the dry matter already consumed by livestock on the site during the winter, there is no difference in yield (see Figure 1). Therefore there is no negative effect of winter grazing on total grassland yield.

At La Blanche Maison, grass growth was measured on different plots. This indicates that there is a slight difference between the two types of grazing in terms of the effect on growth in the spring.

As you can see from Figure 2, which shows the composition at Trévarez, little difference can be seen with regard to the types of vegetation in the grasslands. The composition remains constant, both with and without winter grazing.

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Nutritional value

In terms of nutritional value, Table 1 shows that wintergrass is of good quality. The grass is small and lush and has very good nutritional values. Very little aging occurs. “We see values ​​similar to those of grass in spring or autumn,” says Julien Fortin of the Thorigné-d’Anjou farm.

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“At Thorigné-d’Anjou, the animals gained an average of 500 grams of excess weight each day, which is a very good result. These are the results you would expect from stabled cows that receive hay and silage with occasional carbon correction, because this feed contains on very little carbon,” says Fortin. “We got very good results with 78% winter meadow and 22% hay.”

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“At La Blanche Maison there was sufficient growth for the animals, with an average daily gain of 650 grams for the cattle. There were no significant differences between grazing in rotating fields and free grazing for 24-month-old cattle. In 15-month-old cattle, the difference between Both options are very important. In rotating fields, their growth per day was about 200 units per day, while for free-range cattle it was more than 800 units. These are preliminary results that have not yet been confirmed by repeated observations,” says Lucy Morin. suggest that the divergence may be due to a lack of (permanent) shelter over rotational grazing, which particularly affects younger animals.

“Also in Trévarez, the growth of the animals was more than satisfactory for both methods (classical and organic), with a weight gain of 963 grams and 663 grams per day for the crossbreeds,” reports Tom Duperret. The difference is explained by heterozygous genes in the crosses.

specific savings

For Lucie Morin, there is an advantage in winter grazing in terms of silage, hay and supplementary forage. Other advantages: There is more space in the stables and requires less labor. At the farm in Trivarez, they calculated that for each day the cows were out on winter pasture, 20 minutes less work was needed to feed those animals.

In conclusion, it can be said that during the winter of 2020-2021, the test farms allowed an additional 2.5 months of grazing during the winter grazing, while there was no appreciable effect on the growth of the animals. In the favorable conditions of that previous winter, winter grazing is a great opportunity that you as a livestock farmer should not miss to improve the autonomy of your farm,” says the researcher.

Pierre Yves Lorenzen

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