Restricting daily time at pasture at low and high pasture allowance: Effects on pasture intake and behavioral adaptation of lactating dairy cows

One of the main aims of pasture-based systems of dairy production is to increase the proportion of grazed grass in the diet. This is most easily achieved by increasing the number of grazing days. However, periods of inclement weather conditions can reduce the number of days at pasture. The two objectives of this experiment were: (i) to investigate the effect of restricting pasture access time on animal production, grazing behaviour and dry matter intake (DMI) of spring calving dairy cows in early lactation; and (ii) to establish whether silage supplementation is required when cows return indoors after short grazing periods. In all, 52 Holstein-Friesian spring calving dairy cows were assigned to a four-treatment study from 25 February to 26 March 2008. The four treatments were: full-time access to pasture (22H; control); 4.5-h-pasture access after both milkings (2 3 4.5H); 3-h pasture access after both milkings (2 3 3H); 3-h pasture access after both milkings with silage supplementation by night (2 3 3SH). All treatments were offered 14.4 kg DM/cow per day herbage from swards, with a mean pre-grazing yield of 1739 kg DM/ha above 4 cm, -and were supplemented with 3 kg DM/cow per day of concentrate. The 2 3 3SH treatment was offered an additional 4 kg DM/cow of grass silage by night. Restricting pasture access time (2 3 3H, 2 3 3SH and 2 3 4.5H) had no effect on milk (28.3 kg/cow per day) and solids-corrected milk (27.2 kg/cow per day) yield when compared with the treatment grazing full time. Supplementing animals with grass silage did not increase milk production when compared with all other treatments. Milk protein concentration tended to be lower (P 5 0.08; 32.2 g/kg) for the 2 3 3SH animals when compared with the 22H animals (33.7 g/kg). The grass DMI of the 2 3 3SH treatment was significantly lower (22.3 kg DM/cow per day) than all other treatments (11.9 kg DM/cow per day), yet the total DMI of these animals was highest (16.6 kg DM/cow per day). The 22H cows grazed for 481 min/cow per day, which is significantly longer than all other treatments. The 2 3 3H animals grazed for 98% of the time, whereas the 2 3 3SH grazed for 79% of their time at pasture. Restricting pasture access time did not affect end body weight or body condition score. The results of this study indicate that restricting pasture access time of dairy cows in early lactation does not affect milk production performance. Furthermore, supplementing cows with grass silage does not increase milk production but reduces grazing efficiency.

Section: Discussionsupporting

confidence: 77%

Section: Discussionmentioning

confidence: 99%

Restricting dairy cow access time to pasture in early lactation: the effects on milk production, grazing behaviour and dry matter intake

Kennedy

Curran

Mayes

et al. 2011

“…In recent studies, it has been reported that, with lowto-medium supplementation levels, MY is generally reduced when daily time at pasture, given in one grazing session daily, is ,8 h (Kristensen et al, 2007;Delaby et al, 2008). It is clear that dairy cows can react to a time constraint at grazing through an increase in the proportion of time spent grazing and in PI rate (Kennedy et al, 2009;Pé rez-Ramírez et al, 2009). In these studies, with restricted access time, 90% to 95% of time is spent grazing and PI rate can increase by 30% to 40% when compared to full-time grazing.…”

Section: Variation Of Nutrient Supply At Grazing Relative To Animal Rmentioning

confidence: 99%

“…To maximise cow behavioural adaptation and grazing efficiency, it can be recommended to split access time into two sessions per day, that is, after milking times, particularly at low supplementation level where high PI is expected. In fact, cows seem unable to maintain a high rate of grazing activity during one daily grazing session of 8 to 9 h (Pé rez- Ramírez et al, 2009;Pé rezPrieto et al, 2011), but can maximise proportion of time spent grazing and PI rate during two grazing sessions of 3 to 4 h (Kennedy et al, 2009;Pé rez-Ramírez et al, 2009). PA or sward height, partly determining PI rate, have also been shown to affect the ability of ruminants to adapt to a time constraint (Pé rez-Ramírez et al, 2009).…”

Section: Variation Of Nutrient Supply At Grazing Relative To Animal Rmentioning

confidence: 99%

Managing variations in dairy cow nutrient supply under grazing

Peyraud

Delagarde

2013

Self Cite

Grazed pasture, which is the cheapest source of nutrients for dairy cows, should form the basis of profitable and low-input animal production systems. Management of high-producing dairy cows at pasture is thus a major challenge in most countries. The objective of the present paper is to review the factors that can affect nutrient supply for grazing dairy cows in order to point out areas with scope for improvement on managing variations in nutrient supply to achieve high animal performance while maintaining efficient pasture utilisation per hectare (ha). Reviewing the range in animal requirements, intake capacity and pasture nutritive values shows that high-producing cows cannot satisfy their energy requirements from grazing alone and favourable to unfavourable situations for grazing dairy cows may be classified according to pasture quality and availability. Predictive models also enable calculation of supplementation levels required to meet energy requirements in all situations. Solutions to maintain acceptable level of production per cow and high output per ha are discussed. Strategies of concentrate supplementation and increasing use of legumes in mixed swards are the most promising. It is concluded that although high-producing cow cannot express their potential milk production at grazing, there is scope to improve animal performance at grazing given recent developments in our understanding of factors influencing forage intake and digestion of grazed forages.

“…Studies conducted in conventional pasture-based systems have analyzed the impact of supplementation (Phillips and Leaver, 1986;Sheahan et al, 2011), frequency of pasture allocation (Dalley et al, 2001;Granzin, 2003), pasture height (Gibb et al, 1997) and pasture allowance (Chilibroste et al, 2012), together with available grazing time (Gregorini et al, 2009;Kennedy et al, 2009;Perez-Ramirez et al, 2009), prior fasting (Chilibroste et al, 1997 and2007) and time of the day (Gregorini, 2012) on cow behavior.…”

Section: Introductionmentioning

confidence: 99%

Animal behavior and pasture depletion in a pasture-based automatic milking system

Lyons

Kerrisk

Dhand

et al. 2014

In pasture-based automatic milking systems (AMS), feed is the main incentive that can be managed to encourage reliable and consistent voluntary and distributed cow traffic. Modifying timing, placement and size of feed allocations is expected to have an effect on cow behavior that could avoid the occurrence of extended milking intervals, which have a negative effect on milk yield. Therefore, behavioral studies provide information on how cows modify their actions under different management regimes and can help explain the impact of those regimes. Behavioral observations were conducted in spring 2011 at the FutureDairy AMS research farm, as part of a study where a herd of 175 cows was split into two groups that received supplementary feed either before (PRE), or immediately after (POST) milking. In addition, all cows were offered access to two daily pasture allocations. Observations were conducted in the pasture allocation on 15 focal cows from each treatment group during four periods of 24 h to detect presence and behavior (grazing, ruminating, idling and other) every 15 min. In addition, bite rate and pasture biomass were measured every hour. Overall, despite the finding that more POST cows than PRE cows entered the pasture allocation during the first 8 h of active access, there was no difference in the total proportion of cows that had gained access by the end of the active access period (average 68% for both treatments). Cows in the PRE treatment started exiting the pasture allocation just 6 h after entering, compared with 8 h for POST cows, although their behaviors in the pasture allocation did not differ. Behaviors and bite rate were more dependent on pasture biomass than on supplementary feeding management.