Energy partitioning and substrate oxidation by Murciano-Granadina goats during mid lactation fed soy hulls and corn gluten feed blend as a replacement for corn grain

Abstract

The aim of this experiment was to study the effect of substituting corn grain by soy hulls and corn gluten feed blend on energy partitioning, substrate oxidation, and milk performance in dairy goats during mid lactation. Ten multiparous Murciano-Granadina goats in mid lactation were fed 2 isoenergetic and isoproteic diets [19.08MJ/kg of dry matter (DM) and 18.7% of CP, DM basis] in a crossover design. One group of 5 goats was fed a mixed ration with 373g of corn grain/kg of DM (CRN diet) and the other diet replaced corn grain with 373g/kg DM of fibrous by-products [soy hulls and gluten feed (SHGF) diet]: 227g of soy hulls/kg of DM and 146g of gluten feed blend/kg DM. Fat was added to the SHGF diet to make it isoenergetic. After 10d of adaptation, the feed intake, refusal, total fecal and urine output, and milk yield were recorded daily over a 5-d period. Then, gas exchange measurements were recorded by a mobile open-circuit respirometry system using a head box for 10d. Dry matter intake was similar for both diets (2.07kg/d, on average). Greater and significant values were found in the SHGF diet for ammonia N, energy in urine, and oxidation of protein. Values were significantly lower for heat production of fermentation, indicating a decrease in rumen fermentation with this diet, probably due to an excess of crude protein in the diet and lack of synchronization of the nonfiber carbohydrates with rumen-degraded protein. The metabolizable energy intake was no different between CRN and SHGF treatments, with an average value of 1,444kJ/kg of BW(0.75). Due to the positive energy balance during mid lactation in this trial, most of the heat production from oxidation of nutrients derived from carbohydrate oxidation (55%, on average), followed by oxidation of fat (29%, on average). No significant differences were observed for milk production, although milk fat was significantly greater for the SHGF diet than the CRN diet (7.0 vs. 5.4%, respectively). Despite the different starch levels and fibrous content used in these mixed diets, no significant differences for the efficiency of use of metabolizable energy for late lactation were observed (0.63, on average). An average nutritive value of 7.52MJ of net energy of lactation/kg of DM was obtained. This fibrous by-product was utilized by lactating goats without detrimental effect on energy metabolism and resulted in similar performance to grain bases diet. The economic advantages and sustainability of this choice should be evaluated.

Murciano-Granadina Goat Performance and Methane Emission after Replacing Barley Grain with Fibrous By-Products

“…This value was analogous to those obtained by other authors [ 29 ] with lactating Granadina goats (0.67), and [ 30 ] with Alpine goats during midlactation and 60% of concentrate (0.63). According to [ 31 ], a value for mixed diet in mid lactation of 0.67 for Saanen goats was found, and [ 32 ], with mixed diets and goats at mid lactation and positive energy balance, reported values around 0.63.…”

Energy Balance Data from Lactating Dairy Goats Offered Total Mixed Diets

“…Data from eight energy balance experiments (three unpublished) conducted at the Experimental Farm of the UPV were used to develop the model [10] [11] [12] [13] [14]. All studies had shown the possibility to replace cereal grain with agricultural fibrous byproducts successfully.…”

“…The trials encompassed a total of 267 observations from multiparous Murciano-Granadina goats; six studies in mid and two studies in mid-late lactation. The trial [10] replaced corn grain (37%) with a blend of soy hulls and corn gluten feed and, alfalfa hay was used as forage (forage to concentrate ratio was 45:55) in lactating goats in mid lactation. [11] with lactating goats in mid lactation, studied the effect of replacing corn grain (60%) with citrus pulp (60%) or soy hulls (60%) in a forage to concentrate ratio of 15:85.…”

Influence of Nutrition on Methane Gas Production in Murciano-Granadina Goats

“…Hence, similar OXCHO was obtained than in our study but lower OXF than our trial. So, we expect similar OXF in our SH diet than the blend of fibrous by-product form López and Fernández (2013). These last authors added almost 4% of fat to the fibrous diet and it could be affect fiber fermentation (Palmquist and Jenkins, 1980).…”

“…Few studies relating to oxidation of nutrients are available for ruminants and especially for small ruminants. In the study of López and Fernández (2013) in goats during mid lactation, total mixed diets bases in corn grain was replaced with a blend of fibrous by-product as soy hulls and corn gluten feed. In that trial no differences was observed between diets for OXCHO and OXF (55% and 29% on average, respectively).…”