Digestion of cell wall fractions of forage in the rumen is incomplete due to the complex links which limit their degradation. It is therefore necessary to find options to optimize the use of forages in ruminant production systems. One alternative is to use exogenous enzymes. Exogenous fibrolytic enzymes are of fungal or bacterial origin and increase nutrient availability from the cell wall, which consists of three fractions in different proportions depending on the species of forage: digestible, potentially digestible, and indigestible. The response to addition of exogenous enzymes varies with the type of forage; many researchers infer that there are enzyme-forage interactions but fail to explain the biological mechanism. We hypothesize that the response is related to the proportion of the potentially digestible fraction. The exogenous enzyme activity depends on several factors but if the general conditions for enzyme action are available, the potentially digestible fraction may determine the magnitude of the response. Results of experiments with exogenous fibrolytic enzymes in domestic ruminants are inconsistent. This, coupled with their high cost, has made their use unattractive to farmers. Development of cheaper products exploring other microorganisms with fibrolytic activity, such as Fomes fomentarius or Cellulomonas flavigena, is required.

Simple SummaryPumpkin waste are part of the millions of tons of vegetable residues produced yearly that could be used in livestock feeding. Their value not only relies in its nutritional content as its bioactive compounds could modify meat, milk, and egg composition which are of uttermost value for human nutrition. Furthermore, pumpkin waste, which cannot be used in human consumption, may contribute to diminish human-livestock competition for cropland. In this review, we describe the potential of pumpkin waste as animal feedstock as a strategy for more sustainable livestock production while making emphasis on the importance of food from animal origin in human health.AbstractMeat, milk, and egg contribute positively to the nutrition and health of humans; however, livestock requires a large number of resources, including land for fodder and grains. Worldwide millions of tons of vegetable waste are produced without any further processing, causing pollution and health risks. Properly managed vegetable waste could provide a source of feed for livestock, thus reducing feeding costs. In this regard, pumpkin waste (Cucurbita sp.) is an alternative. Research on pumpkin waste on animal nutrition is scarce, however, it has potential as animal feed not only for its nutritional value but also for its antioxidants, pigments, and polysaccharides content that could enhance quality of meat, milk, and egg, as well animal health. In this review, we describe the environmental impact of livestock as a result of greater demand for food of animal origin, including the importance of the consumption of animal foods in human nutrition and health. Moreover, we emphasize the potential of plant residues and, particularly, on the characteristics of pumpkins and how their use as feedstuff for livestock could improve productivity and modify the composition of meat, milk, and egg.

This study was conducted to evaluate the effect of chihua pumpkin (Cucurbita argyrosperma) residue in ruminal digestibility and gas production in an in vitro assay. Four treatments were evaluated: a control using a standard diet for ruminants elaborated with corn stover, corn grain and soybean meal, and three experimental diets with 10, 20 and 30% dry residue of chihua pumpkin instead of corn stover. Dry matter digestibility and gas production was determined at 24 h of incubation in ruminal fluid obtained from two Holstein cows with a ruminal cannula. Randomized block experimental design was used as and a comparison of means was performed by the Tukey test. The results indicated that dry matter digestibility was significantly increased (P ≤ 0.05), while gas production tended to decrease (P≤0.1) with the addition of residue of chihua pumpkin. Under the conditions of this study, it was concluded that the residue of chihua pumpkin could be an environmentally friendly and ecological alternative for feeding ruminants that can be incorporated into the diet as much as 30% of the ration. However, this study was limited to an in vitro assay; in vivo studies are necessary to evaluate the potential of chihua pumpkin´s residue in the productive performance of ruminants. It would also be appropriate to evaluate the intake behavior, productive performance and nutritional status of animals fed with different forms of processed residue of chihua pumpkin.A key issue for sustainable development of animal production is the efficient use of resources, using feedstuffs that do not compete with human and reducing waste (Wadhwa and Bakshi, 2013). This coupled with the high cost of grains and an increasing demand for meat and milk for human consumption, makes it necessary to search for new alternatives for feeding livestock that positively affect health and productive performance of animals, while reducing production costs. Thus the waste of fruits and vegetables is an ecological and economically viable option to fulfill this purpose. Every year a lot of this waste is generated worldwide and Mexico is no exception. One example is the crop residue of chihua pumpkin (Cucurbita argyrosperma) (ChP). According to the SIAP (2015), in 2014 37,872 hectares of chihua pumpkin were harvested for its seeds in México, generating about 644,000 tons of fresh waste. Seeds of chihua pumpkin have high commercial and economic value, while the rest of the

The aim of this study was to evaluate the animal performance of late lactating grazing dairy cows in response to fresh chopped maize (FCM) supplementation under a small farming system. Twenty-four multiparous Holstein dairy cows were used in a rotational grazing on a mixed alfalfa-orchard grass sward. Three treatments were evaluated: 0, 4, and 8 kg dry matter (DM) of FCM cow(-1) day(-1). The experimental design was a crossover, with three periods lasting 19 days each. There were no differences on individual milk production nor on milk composition. Herbage DM intake decreased (P < 0.0001) from 8.4 to 5.2 and 3.1 kg DM when increasing FCM from 0 to 4 and 8 kg DM, respectively. Total DM intake increased (P < 0.0001) with 8 kg DM of FCM, averaging 14.8 kg. Substitution rate was 0.75 and 0.67 kg of pasture per kilogram of FCM with 4 and 8 kg DM of FCM, respectively. Consequently, stocking rate (STR) increased (P < 0.0001) from 3.8 to 6.2 and 8.8 cows ha(-1), and milk production per hectare increased (P < 0.0001) from 39.3 to 64.5 and 95.5 kg of milk, with 0, 4, and 8 kg DM of FCM, respectively. This means that STR increases 0.63 cows ha(-1), and 0.75 kg of milk ha(-1) when FCM is increased in 1 kg of DM. In conclusion, offering FCM as supplement to grazing dairy cows in their final lactation stage had no benefits in individual milk production or milk composition, but had benefits on milk production per hectare.