Use of sugar cane to feed lactating dairy goats

http://dx.doi.org/10.1590/1678-4162-12022 Arq. Bras. Med. Vet. Zootec., v.72, n.6, p.2297-2307, 2020 Use of sugar cane to feed lactating dairy goats [Uso da cana-de-açúcar na alimentação de cabras leiteiras em lactação] A.M.D. Cabral https://orcid.org/0000-0002-6101-1104 F.F.R. Carvalho https://orcid.org/0000-0001-9211-0263 G.C.L. Santos https://orcid.org/0000-0002-6979-6321 J.C. Ferreira https://orcid.org/0000-0001-6499-9050 M.J.M.S. Silva https://orcid.org/0000-0003-1990-8257 G.R.A. Santos https://orcid.org/0000-0002-7554-9351 G.S. Belo Júnior https://orcid.org/0000-0003-4225-4204 N.D. Melo https://orcid.org/0000-0003-0036-6064 A.M.D. Cabral1, F.F.R. Carvalho1, G.C.L. Santos1, J.C. Ferreira1, M.J.M.S. Silva1, G.R.A. Santos2, G.S. Belo Júnior3, N.D. Melo4 1Universidade Federal Rural de Pernambuco/UFRPE ˗ Recife, PE 2Universidade Federal de Sergipe/UFS ˗ Aracaju, SE 3Aluno de graduação ˗ Universidade Federal de Pernambuco/UFPE ˗ Recife, PE 4Aluna de graduação ˗ Universidade Federal de Campina Grande/UFCG ˗ Campina Grande, PB ABSTRACT The aim of the present study was to assess the effects of replacing corn silage with sugarcane in the diet of lactating Saanen goats and to determine their intake and digestibility of nutrients, ingestive behavior, milk yield and composition. The experimental diets were composed of increasing levels (0, 33, 66 and 100%) of substitution in dry matter (DM). Twelve multiparous Saanen goats, with an average body weight of 45.2kg, average milk yield of 3.0kg day-1, distributed in a triple latin square experimental design (4 × 4) were used. The dry matter intake (DMI) and other nutrients were estimated through the difference between the total nutrient in the food offered and its total in the leftovers. The DMI, crude protein, neutral detergent fiber (NDF) and total digestible nutrients were not influenced, but the apparent digestibility of DM and NDF decreased. Feeding time and feeding efficiency were not influenced, the rumination and total chewing times increased, and the leisure time decreased, both linearly. Milk yield was not influenced by substitution levels, but corrected milk yield to 3.5% fat decreased. Sugar cane represents a dietary alternative for goats with medium milk yield in critical periods of forage, since it does not change the consumption of DM and milk yield, even with the apparent declining digestibility of some nutrients, influencing the ingestive behavior of the animals. Keywords: digestibility, fiber, milk yield, ruminants RESUMO O objetivo do presente estudo foi avaliar os efeitos da substituição da silagem de milho por cana-deaçúcar na dieta de cabras Saanen em lactação e determinar a ingestão e a digestibilidade de nutrientes, o comportamento ingestivo, a produção e a composição do leite. As dietas experimentais foram compostas de níveis crescentes (0, 33, 66 e 100%) de substituição na matéria seca (MS). Doze cabras Saanen multíparas, com peso corporal médio de 45,2kg, produção média de leite de 3,0kg dia-1, foram distribuídas em delineamento experimental triplo quadrado latino (4 × 4). A ingestão de matéria seca (IMS) e de outros nutrientes foi estimada por meio da diferença entre o total de nutrientes nos alimentos oferecidos e o total nas sobras. A IMS, a proteína bruta, a fibra em detergente neutro (FDN) e os nutrientes digestíveis totais não foram influenciados, mas a digestibilidade aparente da MS e da FDN diminuiu. A produção de leite não foi influenciada pelos níveis de substituição, mas a produção de leite corrigida para 3,5% de gordura diminuiu. A cana-de-açúcar representa uma alternativa alimentar para cabras com produção média de leite em períodos críticos de forragem, pois não altera o consumo de MS e a produção de leite, mesmo diminuindo a digestibilidade aparente de alguns nutrientes e influenciando o comportamento ingestivo dos animais. Palavras-chave: digestibilidade, fibra, produção de leite, ruminantes Recebido em 29 de abril de 2020 Aceito em 28 de agosto de 2020 E-mail: Cabral et al. INTRODUCTION For dairy goat breeding the quality of forage is of fundamental importance, as it affects the intake of animals and the apparent digestibility of food, reflecting in the production, and consequently in the commercialization of milk and its derivatives. As reported by Nazli et al. (2018), the corn plant (Zea mays) has been used in the form of silage to feed ruminants in several parts of the world, especially for its high production of dry matter, ease of harvest, suitability for fermentation in silo and high concentration of net energy. Among Brazilian agricultural crops, sugarcane (Saccharum officinarum) ranks second place in the worldwide production ranking (FigueroaRodríguez et al., 2019), given its importance for the generation of sugar and biofuels. However, due to the need to reduce costs in animal feeding and greater economic return to the rearing system, this has been used and shown to be a nutritionally viable food alternative (Oliveira et al., 2019 Cabral et al., 2015; Worku et al., 2015; Nyakira et al., 2015). To Leng (1988), sugarcane has some limitations in relation to its nutritional value, when used as a single food it becomes unbalanced by the low protein content and the characteristics of the fiber present in its cell wall. The structural nature of the neutral detergent fiber is able to inhibit the action of microbial enzymes in the rumen, resulting in a negative correlation between the digestibility and the intake of dry matter (Mcallister and Ribeiro et al., 2016). On the other hand, since it is processed to a reduced particle size, it results in favoring the attack of ruminal bacteria. Nocek and Russel (1988) highlighted the importance of the synchronism between a readily digestible carbohydrate source and the nitrogen available in the rumen, as essential for microbial growth and stimulating the production process. This condition directly influences the ingestive behavior of the animals due to the time spent on feeding, rumination and leisure. Thus, the hypothesis of this work is based on the fact that the energy:nitrogen ratio of the diets through the substitution of corn silage for sugarcane to lactating goats, can favor food intake, digestibility of nutrients and consequently not affect the ingestive behavior and milk yield of goats. Hence, this study aimed to evaluate the effect of replacing corn silage with sugarcane on the intake and apparent digestibility of nutrients, the ingestive behavior, milk yield and composition of lactating Saanen goats. MATERIALS AND METHODS The experiment was carried out in the UFRPE in the Recife metropolitan area which, is located at 08º03’14”S and 34º52’51”W and has a hot and humid climate, with more than 1000mm of rainfall, a mean temperature higher than 18ºC and relative air humidity of between 79.2 and 90.7%. The Ethics Committee of the Universidade Federal Rural de Pernambuco (UFRPE) approved this study under protocol number 2308202170 (...truncated)