Effect of varying total mixed ration particle size on rumen digesta and fecal particle size and digestibility in lactating dairy cows

The objective of this experiment was to evaluate the effects of feeding rations of different particle sizes on rumen digesta and fecal matter particle size. Four rumen-cannulated, multiparous, Holstein cows (104±15 d in milk) were randomly assigned to treatments in a 4×4 Latin square design. The diets consisted of 29.4% corn silage, 22.9% ground corn, 17.6% alfalfa haylage, and 11.8% dry grass hay [20% of forage dry matter (DM)] on a DM basis. Dry grass hay was chopped to 4 different lengths to vary the total mixed ration (TMR) particle size. Geometric mean particle sizes of the rations were 4.46, 5.10, 5.32, and 5.84 mm for short, medium, long, and extra long diets, respectively. The ration affected rumen digesta particle size for particles ≥3.35 mm, and had no effect on distribution of particles3.35 mm. All rumen digesta particle size fractions varied by time after feeding, with soluble particle fractions increasing immediately after feeding and 0.15, 0.6, and 1.18-mm particle size fractions decreasing slightly after feeding. Particle fractions1.18 mm had ration by time interactions. Fecal neutral detergent fiber (NDF) and indigestible NDF concentrations decreased with increasing TMR particle size. Fecal particle size expressed as total geometric mean particle length followed this same tendency. Fecal particle size, expressed as retained geometric mean particle length, averaged 1.13 mm with more than 36% of particles being larger than 1.18 mm. All fecal nutrient concentrations measured were significantly affected by time after feeding, with NDF and indigestible NDF increasing after feeding and peaking at about 12h later and then decreasing to preprandial levels. Starch concentrations were determined to have the opposite effect. Additionally, apparent digestibility of diet nutrients was analyzed and DM digestibility tended to decrease with increasing TMR particle size, whereas other nutrient digestibilities were not different among rations. These results show that the critical size for increased resistance to rumen escape is larger than 1.18 mm and this critical size is constant throughout the day. This study also concludes that, when using average quality grass hay to provide the range of particle sizes fed, DM digestibility tends to decrease with increasing ration particle size

RADICAL SURGICAL TECHNIQUE FOR TREATMENT OF WHITE LINE DISEASE IN DAIRY COWS

Introduction: this clinical research investigates whether rigorous and aggressive surgical debridement of white line disease (WLD) lesions in 236 lame cows, in association with a medicated bandage, would promote clinical healing (as evidenced by coverage of the lesion with new horn) with subsequent improvement in milk production. Materials and methods: after claw trimming, wall and sole horn were removed and the horn rim trimmed around and inside the lesion using a hoof knife, until abundant bleeding was present. The wound was then rinsed, covered with a topical antibiotic and bandaged. Results: out of the initial 236 lame cows, on day two 40 cows were not lame anymore and 196 cows showed a score of 2 out of 5. On day 18, two cows had a grade 4 lameness, with the lesions being smaller but not completely healed. On days 30 and 40, none of the remaining 234 cows developed recurrence of pathology or lameness. At day 60, lesions were completely healed. Discussion: this aggressive surgical treatment allows milk production not to decrease comparing to the control group and can be easily implemented in practice. Conclusions: Since bovine claw lesions represent one of the main problems in dairy cattles, this surgical technique could be suggested as a valid option for the treatment of WLD in cows

Four-Year Monitoring of Foodborne Pathogens in Raw Milk Sold by Vending Machines in Italy

Prevalence data were collected from official microbiological records monitoring four selected foodborne pathogens (Salmonella spp., Listeria monocytogenes, Escherichia coli O157:H7 and Campylobacter jejuni) in raw milk sold by self-service vending machines in seven Italian Regions (n. 60907 samples from 1239 vending machines) during the years 2008 to 2011. Data of samples analyzed both by culture-based and real-time PCR methods were collected in one Region. A total of 100 raw milk consumers in four regions were interviewed while purchasing raw milk from vending machines. One hundred and seventy eight samples out of 60907 were positive for one of the four foodborne pathogens investigated; overall, 18 samples were positive for Salmonella spp., 83 for L. monocytogenes, 24 for E. coli O157:H7 and 53 for C. jejuni in the seven Regions investigated. There were no significant differences in prevalence among Regions, but a significant increase in C. jejuni prevalence was observed over the years. A comparison of the two different analysis methods showed that real-time PCR is from 2.71 to 9.40 times more sensitive than culture-based method. Data on consumer habits showed that some behaviors may enhance the risk of infection due to raw milk consumption: 37% of consumers do not boil milk before consumption, 93% never use an insulated bag to transport raw milk home, and raw milk is consumed by children under five years of age. The study emphasizes that end-product controls alone are not sufficient to guarantee an adequate level of consumer protection. The beta distribution of positive samples in this study and the data on raw milk consumer habits are useful and appropriate for the development of a National Quantitative Risk Assessment of Salmonella spp., L. monocytogenes, E. coli O157 and C. jejuni related to raw milk consumption

DOSSIER / ZOOTECNIA DI PRECISIONE

In questo contributo discuteremo le dotazioni relative alla zootecnia di precisione presenti in una stalla sperimentale universitaria. Questa stalla si trova ad Ozzano nell’Emilia (Bo), sede dell’ex Facoltà di Veterinaria di Bologna, ora Scuola di Agraria e Veterinaria - Dipartimento di Scienze mediche veterinarie (Dimevet), e ha una finalità sia di sperimentazione che didattica, sia per quanto riguarda l’alimentazione e le patologie, sia per quanto riguarda il comportamento e, più in generale, il benessere animale. La stalla sperimentale fa parte dell’Azienda agraria dell’Università di Bologna (Aub) e ospita 80 capi in lattazione, con un intervallo parto-concepimento medio di circa 120 giorni. Le bovine sono trasferite nel settore delle asciutte 60 giorni prima della data prevista per il parto; gli ultimi 20 giorni le passano nel box parto, su lettiera, dove partoriscono. Successivamente, le puerpere sono spostate in un’area a lettiera per un certo periodo di tempo variabile (mediamente 10 giorni) in funzione dello stato di salute della bovina (ad esempio capi a rischio chetosi, ecc.). In questo periodo si applica il seguente protocollo di monitoraggio: rilevamento quotidiano della temperatura corporea (rettale); a 3, 5 e 10 giorni si controlla il livello ematico dei corpi chetonici, lo stato uterino e la consistenza delle feci. Per le vacche in lattazione sono presenti anche tre stazioni di auto alimentatori con la possibilità di erogare tre diversi mangimi

Extruded soybean and flaxseed enhance fat composition of milk for Parmigiano-Reggiano cheese

Twenty Friesian dairy cows were used in an experimental trial to study the effects of extruded full-fat soybean and flaxseed dietary supplementation, at the level authorized by Consorzio of Parmigiano-Reggiano cheese(CPRC) feeding guidelines (1.0 and 0.4 kg/cow/day), on milk production and fatty acid composition. Diet was typically based on alfalfa and mixed hays and cereals. Compared with the concentrations before trial start, CLA and DHA were significantly increased by dietary treatment. These results confirm that the inclusion of extruded full-fat soybean and flaxseed, in the amount authorized by CPRC rules, in the diet of dairy cows is a possible strategy to enhance milk fat composition