Grazing behaviour and intake of two Holstein cow types in a pasture-based production system
Schori F. and Münger A.
Agroscope Liebefeld-Posieux Research Station ALP, CH-1725 Posieux, Switzerland Corresponding author: fredy.schori@alp.admin.ch
Abstract
Cow types adapted to forage-based production systems are of particular interest for organic milk production. The objective of the present study was to compare grass intake and grazing behaviour of New Zealand genetics Holstein cows (HNZ) (n = 11) with farm-bred 'Swiss' Holstein cows (HCH) (n = 11). The comparison was realised in a pasture-based production system with a short late winter/early spring calving season, under organic conditions. Intake of cows was estimated individually 4 times during 2 grazing seasons using the n-alkane marker technique. Simultaneously, selected cows were equipped with behaviour recorders to collect grazing behaviour data. Motion sensors monitored activity and position status. Grass dry matter intake (GDMI) and total DM intake (TDMI) of HNZ were significantly lower than HCH, but per unit of metabolic body weight no differences were found. Energy-corrected milk yield per unit of TDMI shows no significant differences between the two cow types. The HNZ
spent more time ruminating, had a higher number of mastications during rumination, but no differences occurred related to eating and idling time. Fewer bites and more mastications during eating were found for HNZ. The latter tended to stand less and lie more.
Keywords: Grazing behaviour, intake, dairy cow type, pasture, organic farming Introduction
Cow types adapted to forage-based, especially pasture-based production systems are of particular interest for organic milk production. Evidence of genotype x environment interaction exists (Kolver et al., 2002; Horan et al., 2005). Furthermore, McCarthy et al.
(2007) found differences in grazing behaviour between Holstein genetic strains. It seems that some cow breeds or strains fit better into pasture-based production systems with low concentrate supplementation than others. In a comprehensive project including several partners (Swiss College of Agriculture; farmer organisation 'Milk from Pasture', Swissgenetics, Vetsuisse Faculty University of Zurich, University of Veterinary Medicine Vienna and Agroscope) the aptitude of HNZto produce milk in a pasture-based production system with a short calving season late winter/early spring were studied. Grazing behaviour, intake and feed efficiency of HNZ complying with organic guidelines, and with a seasonal calving pattern, are presented in this paper. As comparison HCH are used.
Materials and methods
The study was conducted at the organic farm 'L'Abbaye' in Sorens, Switzerland, (46° 39.767 'N, 7° 3.143' E, 824 m a.s.l.) from 2007 to 2008. Experimental groups consisted of cows with different genetic background, 11 HNZ and 11 HCH, which were in their first (2007) and second lactation (2008), and calved from February to mid April. All lactating cows on the farm, on average 73 animals, grazed together in a full time, rotational system with up to 18 paddocks, each approximately 2 ha. From mid-May to end September no forage supplements were offered. Over the first 105 days (2007) and 80 days of lactation (2008) an average of 405 kg and 316 kg concentrate cow-1 were eaten, respectively. Pre- (PREGSH) and post grazing
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sward height (POGSH) was measured with a rising plate meter (Filip’s folding plate pasture meter, Jenquip, NZ, 1 unit (U) corresponds to 0.5 cm).
Pasture intake was estimated twice in each grazing season, using the double marker method with n-alkanes (Mayes et al., 1986). Five days before the first faecal samples were collected, alkane controlled-release capsules (Captec Ldt., Auckland, NZ) releasing Dotriacontane (C32) at a constant rate of 406 mg d-1 (2007), resp. 402 mg d-1 (2008) were administered into the rumen. Herbage and faecal samples were collected, shifted by 24 hours, each morning during 5 days. Simultaneously, twice 3 cows per type were equipped during 4 days with recorders (IGER Behaviour Recorder, Rutter et al., 1997) to collect grazing behaviour data. Only in 2008, the cows’ physical activity and position status were recorded with pedometers (IceTag, IceRobotics Ltd., Roslin, UK). For statistical analysis, a two-way univariate analysis of variance model was applied (Systat 12, Systat Inc., Chicago, USA) with the factors cow type and measurement period.
Results and discussion
The average sward composition was 74% grasses, 12.5% clover and 13.5% herbs.
Information about measurement date, PREGSH, POGSH and herbage quality are shown in Table 1. The cows had access to pasture during approximately 18 hours daily.
Table 1: Dates, PREGSH, POGSH and herbage quality
Year 2007 2008
Measurement period 1 2 3 4
Dates 10-21 June 26-30 August 25-29 May 17-21 August
PREGSH [U] 16.2 15.4 15.2 15.4
POGSH [U] 9.3 9.4 8.6 8.9
Crude protein in DM [g kg-1] 148 175 172 164
Neutral detergent fibre in DM [g kg-1] 458 437 426 427 Net energy for lactation in DM [MJ kg-1] 5.9 6.1 6.1 6.0 Table 2: Herbage and total intake
Cow type HCH HNZ P
Measurement period 1 2 3 4 1 2 3 4 SEEa Tb Pc TxPd Cows per treatment 10 11 10 9 10 11 10 9
Days in milk 92 166 56 140 109 183 79 166 6 *** *** - Energy-corrected milk [kg] 19.0 16.7 28.3 19.9 15.4 15.0 23.8 18.4 1.0 *** *** - Live weight [kg] 580 592 621 628 475 493 518 538 13 *** *** - Concentrate DM [kg] 2.0 0 3.0 0 0.3 0 1.7 0 0.3 ** *** * Minerals DM [kg] 0.07 0 0.07 0 0.02 0 0.05 0 0.01 *** *** **
GDMIe[kg] 12.0 19.6 18.3 20.2 12.2 17.0 16.4 16.7 0.9 ** *** - TDMIf[kg] 14.1 19.6 21.4 20.2 12.5 17.0 18.1 16.7 0.8 *** *** - GDMIe [kg 100 kg BW-0.75] 10.2 16.3 14.7 16.1 12.0 16.2 15.0 15.0 0.7 - *** - TDMIf [kg 100 kg BW-0.75] 11.9 16.3 17.2 16.1 12.3 16.2 16.6 15.0 0.7 - *** - ECMg TDMI-1 [kg kg-1] 1.36 0.88 1.33 0.99 1.24 0.89 1.34 1.13 0.07 - *** - Significant: t P < 0.10,* P < 0.05, ** P < 0.01, *** P < 0.001 ; astandard error of estimate, bcow type,
cmeasurement period, dinteraction cow type x measurement period, egrass dry matter intake, ftotal dry matter intake and genergy-corrected milk.
Table 2 contains information about lactation stage, milk yield, live weight and herbage as well as concentrate intake., The amount of concentrate eaten differed owing to slight differences in stage of lactation between the cow types. Thus, the grass intake during the first and third measurement period is difficult to interpret. For intake estimation the alkane pair C32 and Tritriacontane was used, based on the results of Berry et al. (2000). Cow type had significant effects on GDMI and TDMI, which are related to body size. Neither intake per 100 kg metabolic body weight (BW0.75) nor milk yield per kg TDMI were different between the two
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cow types. Similar results were obtained by Kolver et al. (2002) and McCarthy et al. (2007).
The measurement period, and therefore stage of lactation, always had a significant influence on GDMI and TDMI. For intake measures no interactions were detected.
For HNZa longer rumination time and a higher number of mastications during rumination were found, but no differences appeared related to eating and idling time (Table 3). Fewer prehension bites and more mastications during grazing were identified for HNZ. The latter tended to make more steps, to stand less and to lie more. McCarthy et al. (2007) noted no differences concerning the ruminating time per day. However, their NZ genetic strain had longer feeding times, and showed lower bite frequencies.
Table 3: Grazing behaviour and physical activity
Cow type HCH HNZ P
Period 1 2 3 4 1 2 3 4 SEEa Tb Pc TxPd
Cows per treatment 6 6 6 5 6 6 6 5
Ruminating time [min d-1] 476 498 480 497 502 529 529 514 13 ** - - Grazing time [min d-1] 602 584 612 572 602 558 599 555 18 - * - Idling time [min d-1] 362 358 348 372 336 353 311 371 20 - - - No. ruminating mastication d-1 32925 34585 31808 33234 34682 35430 36764 34580 1325 * - - No. of boli d-1 591 545 578 572 599 578 642 560 39 - - - No ruminating mastication boli-1 57 66 57 60 60 62 58 63 5 - - - No. prehension bites d-1 (PB) 35833 38696 38634 37559 35019 33992 34520 29739 2190 ** - - No. grazing mastication d-1 (GM) 6936 6776 7719 5401 8135 5657 10708 10989 1237 * t * Total PB and GM d-1 42769 45472 46353 42960 43154 39649 45228 40728 1550 * * - No. idling mastication d-1 1458 1751 1382 1328 1241 876 914 1536 296 t - -
T lying [min d-1] 448 530 504 598 34 t * -
T standing & walking [min d-1] 992 910 937 843 34 t * -
T walking [min d-1] 338 363 378 385 25 - - -
No. steps d-1 3870 4200 4311 4607 211 t - -
Significant: t P< 0.10,* P< 0.05, ** P< 0.01 ; astandard error of estimate, bcow type, cmeasurement period,
dinteraction cow type x measurement period, egrass dry matter intake, ftotal dry matter intake and genergy- corrected milk.
Conclusions
HNZ compared to HCH seems to behave slightly different while grazing, for example with longer rumination time and fewer prehension bites and more mastications during grazing, but differences in intake per BW0.75 and feed efficiency did not occur. Differences in grazing behaviour might be of interest if specific dairy cow types could improve the utilisation of grown herbage.
References
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