AN ALTERNATIVE METHODOLOGY OF DETERMINING FEED SORTING IN TRANSITION DAIRY COWS FED GLYCEROL

• Autor(a) principal: Carvalho, Eduardo Rodrigues de
• Data de Publicação: 2010
• Outros Autores: Lima, Milton Luiz Moreira, França, Aldi Fernandes de Souza, Fernandes, Juliano José de Resende, White, Heather Muse, Donkin, Shawn Scott
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Ciência animal brasileira (Online)
• Texto Completo: https://revistas.ufg.br/vet/article/view/9698
• topic: Animal Nutrition; Nutrição de Ruminantes

The objective of this study was to compare the standard methodology with an alternative method to determine feed sorting in dairy cows during the transition period. Twenty-six Holstein multiparous cows were paired by expected calving date and fed diets containing either glycerol or high moisture corn from -28 through +56 days relative to calving (DRTC). Feed sorting was determined on -16, -9, +9, +15 and +51 DRTC in two different ways. Firstly, it was determined as the actual intake of each screen of the Penn State Particle Separator (PSPS) consumed between 0-4, 4-8, 8-12 and 12-24 hours post feeding, and expressed as a percentage of the predicted intake of that correspondent screen. Secondly, by measuring the particle size distribution of feed consumed between 0-4, 4-8, 8-12 and 12-24 hours post feeding. The total mixed ration (TMR) at feeding and at each time post feeding was separated by size using the 3-screen (19, 8, and 1.18 mm) Penn State Particle Separator (PSPS) to yield long (>19 mm), medium (<19, >8 mm), short (<8, >1.18 mm), and fine particles (<1.18 mm), respectively. Adding glycerol to the prepartum diet increased (P<0.05) the proportion of DM% retained as long particles (>19 mm) and reduced (P<0.05) the proportion of DM% retained as short (<8, >1.18 mm) and fine particles (<1.18 mm), but it did not alter (P>0.05) the proportion of DM% retained as medium particles (<19, >8 mm). Cows fed prepartum glycerol increased (P<0.05) the preference for long particles (>19 mm) according to the standard methodology (77.2 vs. 101.5%, control vs. glycerol) and also in the alternative methodology (9.2 vs. 17.8%, control vs. glycerol). Cows fed prepartum glycerol discriminated against (P<0.05) short particles (<8, >1.18 mm) in the standard methodology (102.6 vs. 94.2%, control vs. glycerol) as well as in the alternative methodology (42 vs. 37.3%, control vs. glycerol). There was no response (P>0.05) of diet on feed sorting of fine particles (<1.18 mm) according to standard methodology during the prepartum interval, but cows fed prepartum glycerol decreased (P<0.05) the preference for fine particles (<1.18 mm) in the alternative methodology (17.9 vs. 13.6%, control vs. glycerol). Cows fed postpartum glycerol increased (P<0.05) the preference for medium particles (<19, >8 mm) according to the standard methodology (108.6 vs. 116.5%, control vs. glycerol), but did not (P>0.05) according to the alternative methodology. Cows fed postpartum glycerol discriminated against (P<0.05) short particles (<8, >1.18 mm) according to the standard methodology (100.6 vs. 96.6%, control vs. glycerol), but did not (P>0.05) according to the alternative methodology. Feeding prepartum glycerol to transition dairy cows increases the preference for the long-stem forage particles of the diet. The alternative methodology proposed in this study is more reliable than the standard methodology to determine feed sorting. KEYWORDS: Biodiesel, byproduct, particle size, preference.