Reduce GHG emissions from the dairy industry – increase efficiency of production; A new approach – when to introduce fresh calved dairy heifers

Reduce GHG emissions from the dairy industry – increase efficiency of production

A new report from Foreign Agricultural Office (FAO), suggests that of the total global anthropogenic  (caused by humans) green house emissions (GHG), the dairy sector accounts for around four per cent of the emissions. A report in 2006 from FAO has stated that 18 percent of the emissions are from livestock sector.

The 4 percent emissions include all the emissions associated with the production, processing and transportation of milk products as well as emissions related to meat produced from animals originating from the dairy system.

Considering just global milk production, processing and transportation and excluding meat production, the sector contributes 2.7 per cent of global anthropogenic GHG emissions.

In 2007, the dairy sector emitted 1,969 MMT of carbon dioxide (CO2) equivalent, of which 1,328 MMT were attributed to milk, 151 MMT attributed to meat from culled dairy animals, and 490 MMT from calves from the dairy sector that were raised for meat. The report does not include emissions from Buffaloes. The CO2 equivalent emission is a standard measurement for comparing emissions of different GHGs.

The global average of GHG emissions per kilogram of milk and related milk products is estimated at 2.4 kg CO2 equivalent.

Methane contributes most to the global warming impact of milk, accounting for about 52 per cent of the GHG emissions in both developing and developed countries.

Methane from enteric (microbial) fermentation represents 20% and manure management 7% of the total CH4 emitted. Ruminants (beef, dairy, goats, and sheep) are the main contributors to CH4 production.

The ruminant animal is unique because of its four stomach compartments: reticulum, rumen, omasum and abomasum. The rumen is a large, hollow muscular organ where microbial fermentation occurs. It can hold 150 to 230 liters of material and an estimated 150 billion microorganisms per teaspoon are present in its contents. The function of the rumen as a fermentation vat and the presence of certain bacteria promote the development of gases. These gases are found in the upper part of the rumen with CO2 and CH4 making up the largest portion, 65.5% and 26.8% respectively.

Considering a fact that the world has 1300 million dairy cattle, each animal would contribute 1.02 MT of CO2. Based on the above, considering the numbers for 2006 as the Dept of AH, India had 8.2 million crossbred animals in production and 28.37 million non descript animals in production and the milk production was 19.244 MMT and 20.415 MMT respectively. The average milk production was 1.087 T/animal/year. The GHG emission would have been 37.37 MMT. As the a report from IFPRI, the estimated cow population in India would be 38.317 million and the production of milk attributed to cows would be about 41% of the total milk production, approximately 44.485 MMT, with an average milk production of 1.16 tons/animal/lactation. Based on the above, Indian cows contribute 39.09 MMT of CO2 equivalents, which in case of US would be only 10.2 MMT, based on the fact that the total population of cows in US is only 10 Million, with an average production of 10 tons/animal/year.

It is important to understand that and identify opportunities where in interventions can be made to reduce the emissions. 

As per a report from Penn State University, research has been conducted in Canada, Australia, Europe and the US on strategies to reduce methane emissions from dairy. The main focus has been on nutritional strategies, including feed higher efficiency feeds, good quality forages etc. Increasing the efficiency of production in which animals use nutrients efficiently to produce milk can result in reduced CH4 emissions. This can be accomplished by feeding high quality, highly digestible forages and grains including balanced rations.

Relatively new mitigation options have been considered and include the addition of such additives as probiotics, acetogens, bacteriocins, organic acids, and plant extracts (i.e. condensed tannins). For the long-term approach though genetic selection of cows that have improved feed efficiency (produce more milk/kg of feed consumed) is the only possibility. 

A new approach – when to introduce fresh calved dairy heifers

An important decision so as the older, resident animals are not aggressive and harm the new entrants in the family. A Report from Queens University, cites that the newly calved heifers should be introduced in the main herd after the second milking (afternoon milking) only. An early morning release may have a negative impact on fresh animals.

Heifers normally have a low social status and could be subjected to increased bullying by older resident females. This could be stressful to the animals and could affect the performance. It has been found that cows are naturally less socially active in the evening and hence less aggressive.

Also it is important that the fresh heifers are introduced 24-36 hours after the calving. 

Amit Sachdev

India Consultant

World Wide Sires

E mail: indiawws@gmail.com