Epsilon Archive for Student Projects

Abstract

Mgbeahurike . A. C. Faecal characteristics and production of
dairy cows in early lactation. Master of Science Thesis. No. 62 ISSN 1403-2201
There is limited information available on the effects of different forages on faecal characteristics in early-lactation dairy cows. In addition, information regarding relationships among dietary variables, production and faecal characteristics is limited. The aim of the present investigation includes 1) determination of the effects
of diets, when differing in forage source, on faecal particle size distribution, consistency, pH and nutrient content as well as on production and body condition scores of early-lactation dairy cows; 2) investigation of potential correlations among dietary, production
and faecal variables; and 3) understanding the principle involved in the use of image analysis to characterize particles from faeces of early lactating dairy cows. Twenty-six herds in Sweden comprising
dairy cows (37.4±17.9 days in milk) of Swedish Red and Swedish Holstein breeds were used in the study. Nine herds used grassclover silage (GCS) as the sole forage, eight herds used GCS combined with whole crop cereal silage (WCCS), four herds used GCS combined with whole-crop maize silage (MS) and five herds used GCS combined with ensiled pressed beet pulp (EPBP). The chemical composition of forages, nutrient contents of the diets and
the formulated intakes were registered. Data were analysed by ANOVA using the GLM procedure of SAS (2001) with herd as the experimental unit. Visit was treated as repeated measure on a herd level. Because no significant treatment by visit interactions were found, data were analyzed as a mean over the two visits. Pearson partial correlation coefficients, with consideration to treatment
effects, were estimated among dietary, production and faecal
variables on a herd level basis (n=26) using the CORR procedure of SAS. Cows fed GCS alone or GCS combined with EPBP tended to have a higher yield of energy-corrected milk (ECM) than cows fed WCCS (P<0.059). For cows fed EPBP in addition to GCS, the higher ECM yield can be related to their higher formulated DM intake (P<0.033) and their improved feed conversion (P<0.040. Cows fed GCS combined with MS or WCCS had a higher faecal NDF concentration in dry matter than cows fed GCS alone or in combination with EPBP (P<0.034). The higher faecal NDF concentration in cows fed GCS and MS was associated with the improved faecal consistency score value by cows fed this diet
(P<0.016). Increased formulated starch intake from concentrate and 10 diet increased the number of long faecal particles (r=0.439* and r=0.390†, respectively). Increased formulated DM intake of forage was associated with decreased faecal DM concentration (r=-0.541**) whereas increasing formulated DM intake of concentrate increased faecal DM concentration (r=0.630**). The strong
positive linear correlation between number of grain kernels in the faeces and faecal starch concentration could be used as a tool to predict faecal starch content (r=0.827***). For the particle size determination by image analysis, gamma distribution curves(density plots) and accumulated distribution curves described and characterized the different particle dimensions in faeces into arithmetic mean particle length, arithmetic mean particle width,
mode particle length, mode particle width, median particle length, median particle width, geometric mean particle length, geometric mean particle width and a 95-percentile fraction. The median length and width values, as well as the 95% length and width values were estimated using cumulative distribution function CDF in SAS. The 95-percentile fraction shows the maximum length or width for 95% of the faecal particles and describes the capacity of rumen to retain large particles. Image analysis can be used for measuring the characteristics, the length and width dimension values, of washed faecal particles.