dairy cows

Bijeenkomst: EGF2015
Auteur: Spörndly E., Andersson S., Pavard N., Le Goc S.
ISBN: 978-9090-289-61-8
Jaar van uitgifte: 2015
Producttype: Paper
In an automatic milking unit, a daytime grazing system with production pasture (group P) was compared with offering cows a small grass-covered paddock only for exercise and recreation, i.e. exercise pasture (group E). Two experiments (Exp1 and Exp2) were performed during 12 and 5 weeks with 53 cows and 42 cows, respectively. Group P was offered new pasture daily with night-time access to grass silage ad libitum (Exp1) or in restricted amounts (Exp2). Group E was offered exercise pasture and silage ad libitum during 24 (Exp1) or 16 hours (Exp2) daily. In Exp1, group P had significantly (P

Bijeenkomst: EGF2015
Auteur: Zom R.L.G., Holshof G., Ipema A.H. and De Mol R.M.
ISBN: 978-9090-289-61-8
Jaar van uitgifte: 2015
Producttype: Paper
An experiment was conducted with the objective of evaluating whether the combined data from grazing and rumen pH sensors could be used to support grazing management. Data were collected during the 2014 grazing season from a 60-cow herd. The average milk yield was 26.1 kg milk cow‑1 day‑1. The cows were housed during the night (16:00-06:00 h) and received 8.4 kg dry matter (DM) of conserved forage cow‑1 day‑1. During the daytime (06:00-16:00 h) the cows were strip-grazed. Daily, the cows were given an edible herbage allowance of approximately 8 kg DM above 5 cm stubble height cow‑1. Automatic milking system visits and milk yields were collected per cow. Concentrates were fed during milking with a transponder-controlled concentrate dispenser. Each cow was equipped with a grazing sensor to measure grazing time. Eight cows were equipped with boluses to measure rumen pH. Milk yield was recorded for each milking and milk composition was recorded weekly. Pre- and post-grazing sward height and herbage composition were recorded daily. Relationships between grass and sensor data and cow performance were derived on the basis of retrospective analysis of milk performance, grazing behaviour and rumen pH data. Rumen pH sensors appear to be of little value. There was no clear relationship between grazing activity and pasture characteristics.

Bijeenkomst: EGF2015
Auteur: Delaby L., Duboc G., Cloet E. and Martinot Y.
ISBN: 978-9090-289-61-8
Jaar van uitgifte: 2015
Producttype: Paper
Efficient grazing management requires anticipation and flexibility and would be greatly facilitated by the development of dynamic tools with the capability to simulate different scenarios based on regular measurement of grass supply on the farm. Pastur’Plan, built on a spreadsheet within a partnership between INRA and a livestock management advisory association (Orne Conseil Elevage), combines two complementary concepts. The first is inspired by the Grass Wedge method adapted to French grazing conditions to highlight the distribution and coherence of grass supply on the paddocks on a farm and the requirements for grass based on the grazing rules and objectives. The second concept allows us to describe the evolution of the balance between grass growth and demand according to various grazing simulations on a paddock-by-paddock basis. This paper describes the hypothesis and calculations implemented, and subsequently the simulation method used and the illustrations dedicated to help support decisionmaking by grazing managers.

Bijeenkomst: EGF2015
Auteur: Lessire F., Hornick J.L. and Dufrasne I.
ISBN: 978-9090-289-61-8
Jaar van uitgifte: 2015
Producttype: Paper
Grazing is more and more abandoned because of increasing size of herds and automation of herd management (e.g. automatic milking system – AMS). In this context, this study aims to evaluate milk production and composition of 2 large Belgian dairy herds equipped with AMS during winter and summer. These herds were followed over 2 years. At grazing, 30% of the offered feed was grass. Milk production in both herds was similar in summer and winter (30.2±7.14 vs 29.7±7.8 in Herd 1 and 26.9±0.8 vs 26.4±0.8 in Herd 2) while milk their composition differed. In conclusion, it is possible for grazing to be preserved even in large herds without noticeably impact on the herd performance.

Bijeenkomst: EGF2015
Auteur: Velarde-Guillén J., Jiménez-Calderón J.D., Martínez-Fernández A. and Vicente F.
ISBN: 978-9090-289-61-8
Jaar van uitgifte: 2015
Producttype: Paper
The emission of methane by dairy cows, as enteric and manure fermentation, is the main source of greenhouse gas (GHG) emission in the dairy sector. The second most important GHG is the N2O emission as a result of nitrogen addition to the soil. An empirical model was used to predict the methane production by dairy cows feeding on two diets based on maize silage grown with organic (MSF) or conventional (ChF) fertilization (IPCC Tier 2) and the emission of N2O by both types of fertilization (IPCC Tier 1). The results were converted to carbon dioxide equivalent (CO2eq) using the Global Warming Potential of 25 and 296 for CH4 and N2O respectively. More than 70% of GHG emissions were due to enteric fermentation. Milk production did not show differences between treatments; however, a 10% higher production of CO2eq kg‑1 of milk was observed in ChF than MSF. The difference observed was due to the diet and not to the type of fertilization, because there were no differences between both soil managements. The results demonstrate that it is possible to reduce GHG emissions with the use of manure and slurry as fertilizers, without affecting milk production.