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In Cuba, the search for new food alternatives for livestock is absolutely necessary, much more so if it is a country with a very high genetic potential in livestock, without an adequate food base for sustenance, which brings serious problems in reproduction and very low growth of the stocking rate (ONEI 2019).
On the island, there are many attempts to solve the nutrient deficit in livestock and to recover the exploitation of its true potential. The use of roots and tubers has been studied for years (García López and García-Trujillo 1990). Recently, Lezcano et al. (2014) tested the Cuban ensiled feed (AEC, initials in Spanish) in monogastric animals and obtained satisfactory results, with high generalization levels on the island.
Biological and chemical silages are produced and used efficiently in animal feeding, from fishing wastes (Díaz 2004 and Marrero et al. 2009). Also, when using cassava root in the elaboration of an enriched silage, encouraging results have been reported (Almaguel et al. 2010). Likewise, total replacement of corn energy by cassava root, ensiled with water and yogurt or vinasse, from alcohol distilleries, has been implemented, with which high liveweight gains have been achieved in growing-fattening pigs (Lezcano et al. 2014).
The plant in which the AEC is prepared can produce 60 t d-1. Silage can be preserved for six months, without losing its nutritional and organoleptic characteristics. This product uses vinasse from distilleries, which is an industrial waste with a high polluting effect. It is useful in ruminant and monogastric animals, and this use contributes to caring for the environment. Sacharomyces cream and B molasses are by-products of the sugar agribusiness, and do not compete directly with human food. Cassava and sweet potato can be equally used, they are even used when they lose their commercial value due to various causes, thus avoiding rotting and contamination. All this justifies a more diversified study in other species. There is no official and stable evidence of the use of this product in ruminants and, specifically, in dairy cows, which are the ones that most experience shortage of quality feed to support their production.
Given these conditions, the objective of this study was to begin the evaluation of AEC in dairy cows under production
Materials and Methods
A total of 20 Siboney de Cuba cows were used to evaluate their productive performance, when consuming, as part of their ration, the AEC. Animals had 135 d of lactation, productions of 7.6 kg of milk/d and body condition of 3 ± 0.1. They were separated into two similar groups in lactation days, initial production and body condition and were distributed in two treatments during dry season: a) 1 kg of commercial feed + 3 kg of Cuban silage + grass, and b) 3 kg of commercial concentrate + grass. The level of substitution selected was established from previous observations. In the experimental group, the concentrate (1 kg) was offered in the morning milking, and the 3 kg of the AEC in the afternoon milking. Meanwhile, in the control, 1.5 kg of concentrate was administered in each milking. Then, cows went to the same pasture to consume the grass.
Animals grazed together, in paddocks of 0.5 ha, sown with star grass (Cynodon nlemfuensis), without fertilization or irrigation. In continuous rotations every 35 d (four during the period), mean availability was 23 kg DM/cow/rotation. Grass protein was between 7.8 and 8.6 % throughout the period and energy was estimated at 8.36 MJ/kg DM. Weighings and milk samplings were carried out every 15 d. They were carried out at the times corresponding to the usual milkings. Analysis of variance was applied and a Milkscan 103 equipment was used for milk analyzes.
Results were analyzed according to a completely randomized design. Infostat package (Robledo et al. 2001) was used for statistical analyzes. The bromatological composition of the ensiled material and dry feed (DF) was determined using the methodology described in the AOAC (2016). This is: dry matter (DM), ash (A), crude protein (CP) (N x 6.25) and crude fiber (CF). Calcium (Ca) and phosphorus (P) were calculated according to Silva and de Queiroz (2004) (table 1).
Table 1 Bromatological composition of the used feed1, %
| Indicators | DM | N | CP | A | CF | Ca | P | pH |
|---|---|---|---|---|---|---|---|---|
|
|
|
|
|
|
|
|
|
|
| SD | 0.99 | 0.20 | 1.25 | 0.83 | 1.36 | 0.25 | 0.03 | 0.06 |
Analyzes conducted at the Institute of Animal Science (ICA)
Twenty samples were analyzed. In milk, fat, protein and lactose contents were determined by the infrared method (FIL-141: B, 1997), using the MilkoScan 103 A/S Foss Electric. In addition, milk corrected by energy (MCE), fat:protein and fat:lactose relations were calculated.
MCA (kg) = (0.038 × g of crude fat + 0.024 × g of CP + 0.017 × g of lactose) × kg of milk/3.14 (Reist et al. 2003).
The microbiological analyzes were carried out to know the hygienic-sanitary quality of the silage produced. The coliform count was performed according to the NC-I20 4832:2002 regulation, total bacteria count according to NC-I20 4833:2002 and fungal count according to NC-I20 7954:2002. For salmonella determination, the procedure was according to regulation NC-I20 7954:2002. The pH was measured by means of a digital potentiometer with a glass electrode, buffer solutions of pH 4 and 7. An electromagnetic shaker was used for sample homogenization.
Results and Discussion
The production of fresh milk and milk corrected by energy during the analyzed period differed significantly in favor of the cows that consumed Cuban silage (table 2), with respect to those that ingested the traditional concentrate. In the former, a greater entry of nutritional factors into the digestive system was evidenced, which are favorable for a production increase (Athuaire et al. 2018 and Lemaire et al. 2019). However, body condition did not indicate improvements in body weight, suggesting that nutrients were targeted at milk precursors, and not weight gain. Probably, in this case, glucogenic factors have predominated, provided by roots and tubers.
Table 2 Response to the use of Cuban silage in milk production and body condition
| Indicators | 3 kg/cow with silage + 1 kg of commercial concentrate + grass | 3 kg of commercial concentrate + grass | SE± and sig. |
|---|---|---|---|
| Production, kg/C/d | 8.7 | 8.1 | 0.15* |
| Milk corrected by energy, kg | 5.7 | 5.4 | 0.09* |
| Body condition | 3.3 | 3.1 | 0.00 |
*p ≤ 0.05
According to table 3, the difference in most of milk components was not significant. However, fat and the fat:protein relation differed between treatments, in favor of the animals that consumed Cuban silage. This could be influenced by the contributions of acetic acid contained in the silage, as well as total solids, which showed higher figures in the animals that ingested Cuban silage.
Table 3 Bromatological composition of milk, %
| Indicators | 3 kg/cow with Cuban silage + 1 kg of commercial concentrate + grass | 3 kg of commercial concentrate + grass | SE± and sig. |
|---|---|---|---|
| Fat, % | 3.9 | 3.7 | 0.06* |
| Protein, % | 2.9 | 2.9 | 0.001 |
| Lactose, % | 4.3 | 4.2 | 0.02 |
| NFS, % | 8.3 | 8.2 | 0.01 |
| Total solids, % | 12.2 | 11.9 | 0.02* |
| Protein/fat | 0.74 | 0.78 | 0.044 |
| Fat/protein | 1.34 | 1.27 | 0.052*** |
| Fat/lactose | 0.90 | 0.88 | 0.045 |
NFS: non fatty solids
*p ≤ 0.05 ***< p ≤ 0.001
As demonstrated in table 3, there was significant variation in milk fat and total solids in cows that consumed Cuban silage, probably due to having greater energy contributions in that ration. It is known that the increased presence of energy can improve the fat within milk as well as, as a consequence, total solids.
Protein:fat and fat:protein relationships were far from reaching high efficiency values. According to other studies, in Holstein breed, fat: milk protein relation is between 1.05 and 1.18 g of fat/g of protein (Čejna and Chládek 2005). Negussie et al. (2013) indicated that the optimal value in Nordic cows can be from 1.25 to 1.45. However, this study showed the highest values in the cows that consumed AEC with respect to those of control treatment, but lower than the previous references. This indicates that supplies must continue to be refined to better match these indicators.
After calving, dairy cows experience energy imbalances, and, due to this, fat concentration tends to increase, and protein concentration to decrease. During this process, fat:milk protein relation increases, indicating a lack of energy in the diet. This evidences a problem of nutritional management in the transition period, and probably after this (Toni et al. 2011).
The microbiological analysis carried out on several silage samples (table 4) showed indicators that were in the range established in the regulations (NC-I20 4833: 2002, NC-I20 7954: 2002 and NC-I20 7954: 2002), issued by the Institute of Veterinary Medicine of the Republic of Cuba (2002) for total bacteria count, coliforms, total fungi count and salmonella (table 4). Growth of these pathogens is limited by acidic pH (3.76), characteristic of the product (Lechevestrier 2005). It is also possible to predict the effect of the yeast Saccharomyces cerevisiae present in the food. It is known that the active elements of its wall, known as mannan and glucan oligosaccharides, are capable of selectively activating the growth of microorganisms in the GIT (Pérez 2000 and Galindo et al. 2010), such as lactobacilli, and of excluding pathogenic bacteria (Blondeau 2001), either due to a reduction in their possibilities of adhesion to the wall or directly due to an antagonistic effect against them (Rodríguez 2010).
Table 4 Microbiological analysis of the Cuban ensiled feed
| Total bacteria count, CFU/g | Coliforms CFU /g | Total fungi count | Salmonella |
|---|---|---|---|
| 2.0-5.0 x 104 | ˂ 102 | 1.4-2.5 x 103 | Negative in 25 g |
The quality demonstrated by AEC, production and quality of milk suggest that studies should be continued to generalize the use of this product in dairy cows, provided that its costs favor its use. Results may indicate a nutritional alternative for dairy farming. In addition, they represent a possibility in terms of substituting feed imports and improving milk productions.
