Nutritional Requirements of Dairy Buffaloes
The nutritional requirements of dairy buffaloes are influenced by several factors related, in particular, to the following three physiological stages: growing period (i.e. heifers), lactation period, dry period. In each phase, the identification of feeds with high nutrient digestibility could reduce the emissions resulting from enteric rumination and increase buffalo farming environmental sustainability (Sabia et al. 2015).
The standard lactation of buffalo cows is 270 days with an average milk production of about 2,200 kg. The peak of maximum production is reached at 50–60 days from calving. Nutritional needs are related to the output of buffalo cows during lactation. The dry matter content of buffalo milk (18.5 %) is much higher than that of cow milk (Claps et al. 2007) and in order to standardise milk production according to fat and protein contents, Di Palo (1992) developed a specific equation. Using this equation Proto (1993) observed that for the production of 1 kg of standardised buffalo milk, 0.44 Milk Forage Unit (MFU) are necessary. According to Zicarelli (1999), the energy content of the feed ration for lactating buffaloes may vary from 0.85 to 0.90 MFU/kg DM and the percentage of crude protein (CP) should be 14–15 %. In fact, this author suggests that 2.47 g of CP per 1 g of milk protein are acceptable levels for a balanced ration; while in early lactation, when the levels of dry matter intake are lower, this value should be increased by 10 % (Campanile et al. 1995).
The dry phase is the period between the end of lactation and the subsequent calving. Although this phase may be considered unproductive by farmers, it is fundamental to obtain satisfactory productive performances in the subsequent lactation. During this period, buffaloes should be provided with a ration capable to fulfil both maintenance requirements and the requirements for an optimal foetal growth, which are particularly high in the last months of pregnancy. The requirements recommended by Proto (1993) for the dry phase of buffaloes are about 0.65 MFU/ kg DM for energy and 10.5 % for CP. In addition, Terramoccia et al. (2005) suggested the use of fresh forages or hay with high biological value and the integration with at least 15 %/kg DM of concentrates. An appropriate ration for this phase should have a low rumen fermentation rate, which promotes the production of volatile fatty acids and improves the proliferation of cellulolytic bacteria. During this phase, a decrease of the absorption process with a drop in the rumen papillae activity is noticed.
Heifer Growth Phase
In many countries growing heifers are reared exclusively on very poor pasture and hay. However, this is not the proper approach from an economic and animal welfare point of view, as the heifer has to reach puberty in the best physical condition. Thus, in order to reduce their unproductive period, heifers have to be fed with proper diets, to obtain high daily gains, and anticipate sexual maturity, conception and first calving. However, the studies on the rearing systems to be used to increase growth rates and reduce the age of puberty of buffalo heifers achieved contrasting results. Borghese et al. (1997), when comparing various intensive rearing systems at different energy levels with a pasture system, found that heifers fed a total mixed ration showed an earlier age of puberty compared with grazing animals. Conversely, Terzano et al. (1996) observed that grazing heifers reached puberty earlier than animals fed corn silage ad libitum, although the latter showed a higher weight at puberty. Similarly, Sabia et al. (2014) found no significant differences in terms of age of puberty between buffalo heifers reared in intensive or extensive conditions, although the weights of puberty were higher in confined animals.