ABSTRACT
To reduce costs, lactating cows are often fed a higher proportion of roughage and alternative feeds; however, such protocols may not lead to optimal milk production. Using a meta-analysis, we evaluated the effects of dietary roughage sources on the composition, voluntary intake, and digestibility of diets fed to crossbred Holstein x Zebu cows under experimental feeding conditions in Brazil. Finally, we assessed the effects of dietary roughage sources on milk yield and composition. The database was composed of 43 experiments with 183 treatments, including 943 lactating cows. The data were obtained from studies published between January 2000 and December 2015. The data were evaluated by analysis of variance, considering the distribution of variables. The diets differed in dry matter and crude protein (CP) contents according to the roughage sources. Diets based on corn silage demonstrated higher intakes of neutral detergent fiber (NDF), CP, and total digestible nutrients, which improved the digestibility of NDF and CP, and resulted in a higher milk yield compared to the diets with one roughage source or those with a combination of two roughage sources. The present study demonstrated that feeding crossbred Holstein x Zebu lactating cows alternative roughage sources compromised milk production and that lactating cows produced higher milk yields when fed corn silage.
Subject(s)
Animal Feed/analysis , Dietary Fiber/metabolism , Digestion , Eating , Lactation/drug effects , Milk/chemistry , Animal Nutritional Physiological Phenomena , Animals , Brazil , Cattle , Diet/veterinary , Dietary Fiber/administration & dosage , Dietary Supplements/analysis , FemaleABSTRACT
A number of studies have addressed the relations between climatic variables and milk composition, but these works used univariate statistical approaches. In our study, we used a multivariate approach (canonical correlation) to study the impact of climatic variables on milk composition, price, and monthly milk production at a dairy farm using bulk tank milk data. Data on milk composition, price, and monthly milk production were obtained from a dairy company that purchased the milk from the farm, while climatic variable data were obtained from the National Institute of Meteorology (INMET). The data are from January 2014 to December 2016. Univariate correlation analysis and canonical correlation analysis were performed. Few correlations between the climatic variables and milk composition were found using a univariate approach. However, using canonical correlation analysis, we found a strong and significant correlation (rc = 0.95, p value = 0.0029). Lactose, ambient temperature measures (mean, minimum, and maximum), and temperature-humidity index (THI) were found to be the most important variables for the canonical correlation. Our study indicated that 10.2% of the variation in milk composition, pricing, and monthly milk production can be explained by climatic variables. Ambient temperature variables, together with THI, seem to have the most influence on variation in milk composition.
Subject(s)
Climate , Milk/chemistry , Animals , Brazil , Cattle , Cell Count , Dairying , Female , Lactation , Retrospective StudiesABSTRACT
O desempenho de ruminantes domésticos é influenciado por fatores intrínsecos ao animal, ao alimento e pela interação entre animal e alimento. O trabalho foi realizado na Estância do 28, pertencente à Fundação Maronna, Alegrete - RS, dentro da APA do Ibirapuitã. Para representar o fator solo, foram escolhidos os três tipos predominantes da APA do Ibirapuitã: Basalto Superficial, Basalto Profundo e Arenito. As amostras da pastagem natural foram retiradas por simulação de pastejo, através de coleta manual. Os parâmetros nutricionais avaliados foram: proteína bruta, fibra em detergente neutro e taxa de degradação da matéria seca. A forragem da pastagem natural oriunda do solo Basalto Superficial apresentou diferença significativa (P<0,05) nos teores de proteína sobre aquelas obtidas dos solos Basalto Profundo e Arenito, os quais não diferiram entre si. O maior teor de fibra em detergente neutro (84,54 por cento) foi obtido na pastagem oriunda do solo Arenito, em relação às originadas dos solos Basalto Superficial e Profundo, com valores de 74,53 e 77,98 por cento, respectivamente. Para a taxa de degradação, também houve uma diferença significativa (P<0,05). A forragem da pastagem natural oriunda do solo Arenito apresentou valor intermediário de degradação 3,61 por cento h-1, não diferindo dos demais solos. As pastagens naturais apresentam taxa de degradação semelhantes durante a primavera e o verão e durante outono e inverno. A forragem da pastagem natural oriunda do solo Basalto Superficial apresentou qualidade nutricional superior, comprovada pela taxa de degradação da matéria seca.
Intrinsic animal and food factors and the interaction between them influence the performance of domestic ruminants. This study was done at Estância do 28, property of the Maronna Foundation, Alegrete - RS, inside the Ibirapuitã Area of Environmental Protection. In order to represent soil as a factor, the three main soil types were chosen: Superficial Basalt, Deep Basalt and Sandy. Hand plucking methods were used to obtain samples of natural pasture. Nutritional parameters considered were crude protein, neutral detergent fiber and dry matter degradation rate. The forage from natural pasture of the Superficial Basalt presented significant difference (P<0.05) in crude protein rates over the other two types of soil, which did not differ amongst themselves. The highest rate of neutral detergent fibre (84.54 percent) was obtained in pasture originated from Sandy soil, in relation to Superficial and Deep Basalt, with values of 74.53 percent and 77.98 percent, respectively. There was also a significant difference in the degradation rate of dry matter (P<0.05). Sandy soil pasture presented an intermediate degradation value (3.61 percent h-1), not differing from other soils. The forage from natural pastures present similar degradation rates during summer and spring and for the period of autumn and winter. The forage from natural pasture of Superficial Basalt type soil presented superior nutritional quality, as could be proved by the dry matter degradation rate.
