Higher NTM leads to less methane

INCREASED LEVEL OF NTM REDUCES METHANE EMISSIONS

When NTM is increased by 10 units in a herd that only uses conventional dairy semen, the amount of methane per kilogram of fat + protein produced is reduced for all breeds. RDC shows the largest reduction in methane by 1.7 percent, while the reduction for Jersey is 1.0 percent and 0.9 percent for Holstein. All three breeds increase the production level by 20 to 23 kilograms of fat + protein, and the replacement rate decreases by 3.3 to 4.3 percent due to better fertility, healthier cows, and 4-5 extra heifers for sale.

The higher production requires higher feed intake, but for RDC, the increased feed intake is lower than for the other two breeds. This is mainly due to RDC having the greatest correlation between NTM and saved feed.

No use of sexed semen and beef semen	RDC		Jersey		Holstein
	0 NTM	+10 NTM	0 NTM	+10 NTM	0 NTM	+10 NTM
Kg of fat and protein	803	826	802	822	873	896
Replacement rate (%)	35.7	32.4	31.3	27.4	33.3	29.0
Sold heifers	8	12	10	14	9	14
Percentage reduction of methane	–	1.7	–	1.0	–	0.9

Table 1: Effects of + 10 NTM in the scenario without the use of sexed semen for the breeds Holstein, RDC, and Jersey. The percentage reduction in methane is based on grams of methane per kilogram of produced fat + protein.

ACHIEVE A METHANE REDUCTION

For the calculation with 0 in NTM, sexed semen is used on all heifers and 35 percent of the cows at the first two inseminations. Beef semen is used on the remaining 65 percent of the cows. For the calculation with +10 in NTM, the use of sexed semen on cows is reduced to 25 percent, and the use of beef semen is increased to 75 percent. This is because the replacement rate can be lowered due to better fertility and health. The increased use of beef semen results in approximately 10 crossbred calves extra per year, with 45-47 crossbred calves in the calculation with 0 in NTM and 55-58 crossbred calves produced per year in the calculation with +10 in NTM.

For all three breeds, production increases by 7 to 14 kilograms of fat + protein, and the replacement rate decreases by 5.6 to 5.7 percent when NTM is increased by +10. The lower increase in production compared to no use of sexed semen is caused by fewer calvings, resulting in fewer cows in early lactation and more cows in late lactation due to better longevity. The lower replacement rate and use of beef semen mean that the number of replacement heifers decreases by 15-20 heifers per 100 cows.

When NTM increases by 10 units, RDC has a decrease of 4.6 percent in grams of methane per kilogram of produced fat + protein, while the reduction is 2.5 percent for Jersey and 2.2 percent for Holstein. This means that the reduction in grams of methane per kilogram of fat + protein when NTM increases by 10 units is 2.5 to 2.75 times higher when sex-sorted semen and beef semen are used intensively. The methane reduction when NTM increases is therefore also dependent on the breeding strategy used in the herd. The reason for the difference between breeds is once again a lower increase in feed intake for RDC compared to the other two breeds.

Use of sexed semen and beef semen	RDC		Jersey		Holstein
	0 NTM	+10 NTM	0 NTM	+10 NTM	0 NTM	+10 NTM
Kg of fat and protein	799	813	809	817	877	884
Replacement rate (%)	35.8	30.2	31.2	25.5	32.9	27.3
Sold heifers	105	85	85	70	89	74
Percentage reduction of methane	–	4.6	–	2.5	–	2.2

Table 2: Effect of +10 NTM in the scenario with intensive use of sex-sorted semen and beef semen, for Holstein, RDC, and Jersey. The percentage reduction in methane is based on grams of methane per kilogram of produced fat + protein.

USE NTM TO OBTAIN MORE ENVIRONMENTALLY FRIENDLY COWS

Choosing bulls based on NTM – regardless of breed – results in more profitable cows while simultaneously reducing methane emissions per kilogram of produced fat + protein. If you combine this with intensive use of sexed semen and beef semen, you will achieve an even greater reduction in methane emission.