Some Factors Affecting Milk Production From Grassland at the Hannah Institute, 1951–70

Castle, M. E.; Macdaid, Elizabeth; Watson, J. N.

doi:10.1111/j.1365-2494.1972.tb00691.x

Cited by 9 publications

(8 citation statements)

References 10 publications

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“…This is consistent with earlier research findings (Castle et al, 1968(Castle et al, , 1972Gordon, 1973;Fales et al, 1995) in which milk production per hectare increased with increasing SR irrespective of the effect of SR on milk yield per cow. In fact, Castle et al (1972) reported that SR explained 92% of the variation in milk production per hectare. Irrespective of SR, there was no significant (P = 0.25) effect on the amount of milk produced per kilogram of feed consumed (0.9 kg of milk/kg of pasture + silage consumed).…”

Section: Milk Production Bw and Bcssupporting

confidence: 93%

“…Stocking rate (SR) is defined as the number of animals allocated to an area of land (i.e., cows/ha), and it has been recognized as the primary driver of milk production per hectare and profitability in grazing systems for over half a century (McMeekan, 1956;Castle et al, 1972). Extension of short-term studies investigating the effect of pasture allowance on DMI and pasture utilization indicates an increase in pasture utilization and a decrease in per cow production as SR increases (Castle et al, 1968;Gordon, 1973;Baker and Leaver, 1986;Kennedy et al, 2006), and this is consistent with full lactation studies (Dillon et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

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Effect of Stocking Rate on Pasture Production, Milk Production, and Reproduction of Dairy Cows in Pasture-Based Systems

Macdonald

Penno²,

Lancaster

et al. 2008

Journal of Dairy Science

211

297

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Ninety-four cows were randomly allocated to 1 of 5 stocking rates (2.2, 2.7, 3.1, 3.7, and 4.3 cows/ha) in a completely randomized design for 3 years. Herds were seasonal calving, with only minor differences in grazing management to optimize the profitability of each stocking rate (SR). Pasture production and quality data, milk and milk component data, and reproduction data were collected, averaged for SR treatment, and linear and quadratic contrasts on SR were evaluated. In addition, the Wilmink exponential model (y(t) = a + b x e((-0.05t) )+ c x t) was fitted to milk yield within lactation, and the parameters were averaged by SR treatment and analyzed as above. The median variation explained by the function for individual lactations was 84%. The amount of pasture grown tended to increase, and the quality of the pasture on offer increased linearly with increasing SR, reducing some of the negative impact of SR on the availability of pasture per cow. Milk production per cow declined linearly with increasing SR, although there was a tendency for most production variables to decline quadratically, with the negative effect of SR declining with increasing SR. The effect on milk production per cow was primarily because of a lower peak milk yield and a greater post-peak decline (less persistent milk profile), although a decline in lactation length with increasing SR was responsible for 24% of the effect of SR on milk yield. Milk production per hectare increased linearly with increasing SR, and there was only a small difference (approximately 3%/cow per ha) in the efficiency of converting feed dry matter into milk energy. Stocking rate did not affect reproductive success. The data are consistent with the need for a more robust measure of SR than cows per hectare because farms will differ in the genetic merit of their cows and in the potential to produce pasture. We introduce the concept of a comparative SR, whereby the carrying capacity of the farm is defined by the BW of the cows, the potential of the land to produce pasture, and the amount of supplement purchased (kg of BW/t of feed dry matter). The adoption of such a measure would facilitate the extrapolation and transfer of research findings among systems.

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Section: Milk Production Bw and Bcssupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Effect of Stocking Rate on Pasture Production, Milk Production, and Reproduction of Dairy Cows in Pasture-Based Systems

Macdonald

Penno²,

Lancaster

et al. 2008

Journal of Dairy Science

211

297

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“…observed within these results emphasise the appropriateness of the techniques applied in this study. Castle et al (1972) reported that over 19 years, SR and milk yield per cow explained 85% of the variation in total milk production. The impact of a one cow/ha SR increase on milk production per ha within the current data set (20.1% and 19.6% for Type I and Type II experiments, respectively) is similar to the findings of Journet and Demarquilly (1979) when comparing raw mean effects on similar data.…”

Section: Discussionmentioning

confidence: 99%

Meta-analysis of the impact of stocking rate on the productivity of pasture-based milk production systems

McCarthy

Delaby

Pierce

et al. 2011

Animal

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The objective of this study is to quantify the milk production response per cow and per hectare (ha) for an incremental stocking rate (SR) change, based on a meta-analysis of published research papers. Suitable experiments for inclusion in the database required a comparison of at least two SRs under the same experimental conditions in addition to details on experimental length and milk production results per cow and per ha. Each additional increased SR treatment was also described in terms of the relative milk production change per cow and per ha compared to the lower base SR (b_SR). A database containing 109 experiments of various lengths with 131 comparisons of SR was sub-divided into Type I experiments (common experimental lengths) and Type II experiments (variable experimental lengths). Actual and proportional changes in milk production according to SR change were analysed using linear mixed model procedures with study included as a random effect in the model. Low residual standard errors indicated a good precision of the predictive equations with the exception of proportional change in milk production per cow. For all milk yield variables analysed, the results illustrate that while production per cow is reduced, a strong positive relationship exists between SR and milk production per ha. An SR increase of one cow/ha resulted in a decrease in daily milk yield per cow of 7.4% and 8.7% for Type I and Type II data, respectively, whereas milk yield per ha increased by 20.1% and 19.6%, respectively. Within the Type II data set, a one cow/ha increase in SR also resulted in a 15.1% reduction in lactation length (equivalent to 42 days). The low predictability of proportional change in milk production per cow according to the classical SR definition of cows per ha over a defined period suggests that SR may be more appropriately defined in terms of the change in available feed offered per animal within each treatment.

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“…The main factors affecting milk yield of the grazing dairy cow include herbage mass (HM), pasture allowance (PA), grazing management, and supplementation (Combellas and Hodgson, 1979;Peyraud et al, 1996). Stocking rate is considered the primary driver of milk output per hectare and of profitability in grazing systems (Castle et al, 1972).…”

Section: Introductionmentioning

confidence: 99%

Effect of pregrazing herbage mass and pasture allowance on the lactation performance of Holstein-Friesian dairy cows

McEvoy

O’Donovan

Kennedy

et al. 2009

Journal of Dairy Science

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The objective of this study was to investigate the effect of pregrazing herbage mass (HM) and pasture allowance (PA) on the grazing management and lactation performance of spring-calving dairy cows. Sixty-eight Holstein-Friesian dairy cows (mean calving date, February 6) were randomly assigned across 4 treatments (n = 17) in a 2 x 2 factorial arrangement. The 4 treatments consisted of 2 pregrazing HM (>4 cm) and 2 PA (>4 cm): 1,700 kg of dry matter (DM)/ha (medium, M) or 2,200 kg of DM/ha (high, H), and 16 or 20 kg of pasture DM/cow per day. The experimental period lasted 30 wk. The experimental area was divided into 4 farmlets, with 1 farmlet per treatment. Mean HM throughout the experimental period was 1,767 kg of DM/ha (M HM) compared with 2,358 kg of DM/ha (H HM). Offering an M HM sward resulted in significantly greater milk protein yield (+31.7 g/d) and lower mean body weight (-12.8 kg). The body condition score change was significantly smaller (-0.21) with the M HM treatments compared with the H HM treatment (-0.34). Milk solids output per hectare was 6% greater on the M HM treatments compared with the H HM treatments. Increasing PA significantly increased milk (+0.9 kg/d), solids-corrected milk (+0.7 kg/d), protein (+43.9 g/d), and lactose (+52.7 g/d) yields. Mean body weight was also significantly greater for cows offered 20 kg of PA (+11.4 kg/cow). It was concluded that in rotational grazing systems, adapting the concept of grazing M HM pastures (1,700 kg of DM/ha) will result in increased sward quality and increased milk solids output per hectare. At medium levels of pregrazing HM, offering animals 20 kg of DM PA will result in increased milk yield per cow.

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Some Factors Affecting Milk Production From Grassland at the Hannah Institute, 1951–70

Cited by 9 publications

References 10 publications

Effect of Stocking Rate on Pasture Production, Milk Production, and Reproduction of Dairy Cows in Pasture-Based Systems

Effect of Stocking Rate on Pasture Production, Milk Production, and Reproduction of Dairy Cows in Pasture-Based Systems

Meta-analysis of the impact of stocking rate on the productivity of pasture-based milk production systems

Effect of pregrazing herbage mass and pasture allowance on the lactation performance of Holstein-Friesian dairy cows

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