@article {3672,
	title = {Evaluating loafing surfaces for off-paddock facilities on New Zealand dairy farms},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {82},
	year = {2022},
	month = {01/2022},
	pages = {22-27},
	address = {Online},
	abstract = {Off-paddock wintering facilities need loafing surfaces that meet animal welfare requirements. Our objectives were to establish relationships between dairy cow behaviour and firmness (comfort) and traction (non-slip) across four different loafing surfaces. The four surfaces were post peelings (woodchip), a 50 mm shredded rubber playground surface with 6 mm geotextile overlay (NUMAT), a 25 mm rubber and plastic chip sports turf underlay with 6 mm geotextile overlay (Tiger Turf), and 25 mm {\texttimes} 1 m2 interlocking rubber matting (NUMAT). Average daily cow lying times were 11.5, 11.0, 10.5 and 8.0 hours/day for post peelings, shredded rubber, rubber/plastic chip, and rubber matting, respectively. A Clegg hammer impact soil tester (2.25 kg) used for mechanical measures of firmness (comfort) showed a strong negative curvilinear relationship with lying times. A Rotational Traction Tester for measuring traction (non-slip) indicated the least to most slippery surface was post peelings followed by shredded rubber, rubber/plastic chip, and finally, rubber matting, which aligned with anecdotal observations of slipping events. Threshold values for these mechanical tests are proposed that will help with evaluating innovative surfaces for cow comfort without the need for animal trials.

},
	issn = {1176-5283},
	author = {Beukes PC and Dela Rue B and Dalley DE and McCall D}
}
@article {3672,
	title = {Effects of a daily dose of zeolite on rumen ammonia of lactating dairy cows consuming fresh-cut ryegrass pasture},
	journal = {New Zealand Journal of Animal Science and Production},
	volume = {78},
	year = {2018},
	month = {07/2018},
	pages = {137-141},
	address = {Lincoln},
	abstract = {Zeolites are aluminosilicates that can be safely fed to ruminants on a daily basis. They have a strong affinity for cations, including
ammonium (NH4
+), which creates the potential to adsorb excess ammonium released in the rumen and reduce urinary nitrogen (N)
excreted. The main objective of this proof-of-concept study was to evaluate the effect of a single dose of 300 g of zeolite, deposited
into the rumens of cannulated dairy cows before the main morning meal of fresh-cut ryegrass pasture, on changes in rumen
ammonium concentrations over the following 8 h. The two-week trial was a cross-over design with 12 cows, either fed ryegrass
as a sole diet (Control) or with zeolite (Zeolite). There was a consistent trend for rumen ammonium concentrations in the zeolitetreated
cows to increase more slowly over time, and were lower than control cows 8 h after the zeolite was given (P = 0.08). This
study provides some indications that a daily dose of zeolite, fed at the onset of the morning meal, may have a moderating effect on
rumen ammonium concentration, and reduce plasma urea N concentrations in lactating dairy cows fed a ryegrass-dominant diet.},
	issn = {1176-5283},
	author = {Beukes PC and Gregorini P and Waghorn GC and Selbie PB}
}
@conference {3729,
	title = {Farming within limits {\textendash} can system fundamentals be the key?},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {74},
	year = {2014},
	month = {06/2014},
	pages = {241-244},
	address = {Napier},
	abstract = {The design of dairy systems with increased production and profit, but reduced environmental footprint, presents a problem with objectives that are seemingly at odds. We argue that this is why we have to go back to the ecological principles that underpin farm systems and use these to develop new systems that will achieve the above objectives. Healthy topsoil is a living nutrient trap. It requires long term thinking and action to achieve and maintain healthy topsoil. The rumen is a very complex ecosystem with the microbes as a key component. Farm systems aimed at optimal performance per cow, with lowest possible methane and urinary nitrogen waste products consistent with this performance, need to ensure effective rumen function. Maintenance dilution and cow longevity are important principles for sustainable and profitable farming. Pastoral livestock systems need ecological and financial buffers to remain resilient in uncertain times. We present a plan consisting of five strategies, based on some of these fundamentals, that we believe is a step towards farming profitably and within limits. },
	issn = {1176-5283},
	author = {Beukes PC and Romera AJ and Clark DA}
}
@conference {89260,
	title = {Modelling the effect of temporary once-a-day milking durinmg early lactation on dairy farm production and profitability},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {73},
	year = {2013},
	month = {Jan},
	pages = {21-25},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {<p>The DairyNZ Whole Farm Model was used to predict the effect of temporary once-a-day (OAD) milking during the calving period on milksolids (MS) production, farm profitability and herd body condition score (BCS) at dry-off. Farms from three regions and three independent seasons were modelled for: wholeseason twice-a-day (TAD) milking of all cows (Control), OAD milking of all cows for eight days immediately post-calving and TAD milking thereafter (Col OAD), OAD milking of the herd for three weeks from the planned start of calving (PSC) and TAD milking thereafter (3 wk OAD), and OAD milking of the herd for six weeks from the PSC and TAD thereafter (6 wk OAD). Model outputs indicated MS production (kg/ha) losses of 2, 1.2 and 3.7\% and profit ($/ha) losses of 6.5, 4.5 and 11.6\% for the Col OAD, 3 wk OAD and 6 wk OAD regimes, respectively. Slight improvements in dry-off BCS were predicted for the OAD milking regimes, comparedwith the control. Milking the herd OAD for three weeks from the PSC may be the prefered strategy to offer labour, lifestyle and animal health benefits with the smallest losses of MS production and farm profit.</p>
},
	issn = {1176-5283},
	author = {Khaembah EN and Rius AG and Beukes PC and Levy G and Gregorini P and Roche JR and Kay JK and Phyn CVC}
}
@conference {79015,
	title = {Identification of cost-effective management options for reducing greenhouse gas emissions by 10\% on a dairy farm in Waikato, New Zealand},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {72},
	year = {2012},
	month = {Jan},
	pages = {181-185},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {An optimisation model of a dairy farm was built to estimate the cost of mitigation of greenhouse gas emissions (GHG-e). First, the Farmax and Overseer models were used to describe production, profitability, and emissions to the environment of a medium-input dairy farm system for the Waikato-Bay of Plenty region of New Zealand. This process allowed generation of a valid and consistent set of input data for a detailed nonlinear programming model able to optimise resource use. The optimisation model was then used to investigate how producers may best respond to the introduction of a 10\% restriction on GHG-e, with and without the use of strategic changes to their farm system to mitigate GHG-e. Profit decreased by 8\% when the restriction was introduced without the availability of strategic mitigation options. The variables that changed most to achieve the reduction were nitrogen fertiliser input, which was reduced by 58\%, and stocking rate which was reduced by 7\%. In contrast, profit increased by 5\% when strategic mitigation options were used under GHG-e restrictions. Using high genetic merit cows was enough to achieve this increase in profit under the emissions constraint.},
	issn = {1176-5283},
	author = {Adler AA and Doole aj Romera GJ and Beukes PC}
}
@conference {60935,
	title = {Using an existing intake model to demonstrate relationships between herbage allowance, hunger drive, days in milk and actual intake in grazing dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {69},
	year = {2009},
	month = {Jun},
	pages = {28-31},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {A sheep intake model was adjusted for dairy cows and used to illustrate intake in relation to inherent hunger, days in milk (DIM), and herbage allowance. Intake is predicted by an exponential function of pregrazing herbage mass, stocking density and hunger drive (k). In adjusting the model, k was re-parameterised using a data set of n = 1,198; it was then adjusted to represent intake decline from peak to end of lactation. This adjustment resulted in splitting k into a and b. Parameter a represented inherent hunger and b its persistence during lactation. The re-parameterised model was tested against an independent data set (n = 287). The square root of mean prediction error was 1.57, indicating good prediction accuracy. Data from three different cow strains, New Zealand-70 and -90 and North American-90 (n = 210, 293 and 271, respectively) were used to reestimate a and b, and to illustrate inherent hunger drive. a and b differed (P <0.01) between strains. Then, with the adjusted and re-parameterized models, the interaction effect of herbage allowance, strain, and DIM on intake were simulated. The adjusted model offers an easy-to-use tool to compare, interpret and illustrate feeding scenarios. },
	issn = {1176-5283},
	author = {Gregorini P and Romera AJ and Beukes PC and Rossi JL and MacDonald KA}
}
@conference {41995,
	title = {Quantifying the importance of submission rate to artificial breeding on reproductive performance and profitability in dairy cattle herds},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {67},
	year = {2007},
	month = {Jan},
	pages = {285-292},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Wanaka},
	abstract = {Dexcel{\textquoteright}s Whole Farm Model (WFM) allows the user to construct a mating policy using dates for anoestrous treatment, artificial breeding (AB) and bull mating with corresponding levels of heat detection efficiency. The model then predicts the outcome of the mating programme for each individual animal using an approach based on physiological events, represented by algorithms incorporating current best knowledge. Four commercial dairy farms were initialised in WFM by describing the farm set-up and management decisions for the 2005/06 season. A range of feeding, production and reproduction indicators was used to validate the model predictions against that observed. All four farms had an observed 3-week submission rate (SR) of about 90\%. An alternative scenario with SR at80\% was created for each farm by simulating reduced oestrous detection efficiency during AB. The eight scenarios were then run for 20 random simulations over three consecutive years. The trend was for SR 90\% to result in more milksolids in the second and third years, improved reproductive outcomes and, despite higher AB costs, an increased (P<0.05) economic farm surplus of $80+/ha. This exercise demonstrated that the WFM is capable of simulating reproductive performance in dairy herds and holistically linking this performance to productivity and profit over successive seasons.},
	issn = {1176-5283},
	author = {Beukes PC and Tiddy RM and Burke CR and Levy G and Lancaster JAS}
}
@conference {41621,
	title = {Predicting cow production based on an estimate of animal genotype within a whole farm model},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {93-97},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {Body condition score (BCS) has been proposed for inclusion in the New Zealand national dairy index, Breeding Worth (BW), to account for replenishment of body tissue. Currently, the breeding objectives model positively accounts for body tissue mobilisation (through extra yield), but not the negative cost of replenishing body tissue. Two methods have been proposed: 1) Including BCS directly into BW by calculating and assigning an economic value to BCS and 2) Adjusting liveweight Breeding Values (BVs) for BCS, which would mean that liveweight BVs would beexpressed at a constant BCS (indirect method). Energy equations were used to calculate the direct economic value for BCS and included a sensitivity analysis. With an economic weight of $25, the percentage emphasis of BCS in BW would be 3.4\%. Including BCS in BW, either directly or indirectly, had little impact on sire rankings (rank correlations with and without BCS within breed were >0.99) and would only have a small impact on the economic response of BW ($0.02 net /cow/annum) and the improvement in BCS(0.006 BCS units/cow/annum). It is concluded that there would be little benefit to including BCS as an independent trait in BW. Body condition score is already included as a predictor in the genetic evaluation of fertility and breeding values for BCS will be estimated routinely from the fertility model.},
	issn = {1176-5283},
	author = {Beukes PC and Palliser CC and Lancaster J and Leydon-Davis C and Levy G and Folkers C and Macdonald K and Thorrold BS and Montgomerie B and Wastney M}
}
@conference {41610,
	title = {Using a whole farm model to explore options for feed grown on-farm to achieve 1750 kg milksolids per hectare in the Waikato},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {29-34},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {Dexcel{\textquoteleft}s Whole Farm Model (WFM) is a computer model of a dairy farm that simulates individual cows and paddocks, with pasture growth driven by observed climate data and with management policies guiding decisions on a daily basis. The aim of the study was to design a farm system to produce 1750 kg milksolids (MS)/ha/yr from feed grown on-farm. An average predicted pasture growth curve was derived by initialising the WFM for a typical all-pasture Waikato farm (3 cows/ha) with "best practice" management policies and running the simulation for 29 years of Ruakura climate data. The model was then used with this average growth curve to design the high producing system. Pasture growth alone (17.3 t DM/ha) did not fulfil the feed requirement for the 1750 kg MS/ha scenario, with an overall feed deficit of 3.1 t DM pasture/ha. Improvements in ryegrass cultivars and N-fertilisers could be expected to increase pasture production by around 10\%, reducing the overall feed deficit to 1.6 t DM pasture/ha. These improvements together with irrigation at 2 mm/day over the three summer months (Dec - Feb) reduced the feed deficit to zero. Irrigation could be replaced by cropping between 11\% and 20\% of the farm in a rotation of annual ryegrass yielding 7 t DM/ha and maize yielding 22 to 28 t DM/ha respectively. },
	issn = {1176-5283},
	author = {Beukes PC and Clark CEF and Wastney ME and Palliser CC and Levy G and Folkers C and Lancaster JAS and Leydon-Davis C and Thorrold BS}
}
@conference {41568,
	title = {Modelling dairy system efficiencies},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {203-208},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {The Dexcel Whole Farm Model (WFM) is being developed to simulate dairy systems based on the interaction of system components. The WFM was fitted against observed data from the Resource Efficient Dairying (RED) trial, Scott Farm, Hamilton (Treatment A, 2002/2003 season) and used to explore the effects of different stocking rates on measures of system efficiency, i.e. feed utilisation (FU) and feed conversion efficiency (FCE). At the same stocking rate as RED treatment A (3 cows/ha), and with the observed {\textquoteleft}bestpractice{\textquoteright} management principles in place, the WFM predicted a FU 7\% higher compared with the observed (73\% vs 66\%). Increasing stocking rate in the WFM resulted in an increase in FU, but the predicted FCE did not decrease as was expected. The model showed the importance of adhering to proven management principles to reduce feed wastage and thereby improve system efficiencies.
Key words: stocking rate; simulation modelling; pasture utilisation; dairy farm. },
	issn = {1176-5283},
	author = {Jensen RN and Beukes PC and Clark DA and MacDonald KA}
}
@conference {41554,
	title = {Modelling the effects of zero-inductions on profitability in dairy systems},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {132-136},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Inductions are an animal welfare issue and regulations aim to achieve < 2\% inductions on a national basis by 2010. There is a need to assess the longer-term impacts of alternative reproduction management strategies on farm economics and their success in solving the problem of poor reproductive performance. Dexcel{\textquoteright}s Whole Farm Model was calibrated against observed data from Lincoln University Dairy Farm where 11\% of the herd was subjected to inductions in the 2002/03 season, but a zero-induction policy has since been adopted. Results from one-year simulations over five different climate years showed a significant decrease in farm profit ($105/ha, P < 0.05) from the benchmark farm with 11\% inductions (following {\textquoteleft}best practice{\textquoteright} guidelines) to a farm where the late-calvers were culled and replaced by bought-in early-calving heifers and where stocking rate was raised moderately (< 10\%) to compensate for the higher proportion of heifers in the herd. Multiple-year simulations reflecting carry-over effects showed that a strategy with a 10-week mating period, annual culling of 25\% of the herd including all empties and replacement with synchronized heifers mated to start calving one week before planned start of calving can match the farm profitability of the {\textquoteleft}Induction{\textquoteright} strategy if implemented consistently for 5-8 years.
Key words: calving spread; modelling; synchrony; mating; replacement. },
	issn = {1176-5283},
	author = {Beukes PC and Thorrold BS and Wastney ME and Glassey CB and Burke CR and Van Bysterveldt AM}
}
@conference {41512,
	title = {Modelling farm systems with once-a-day milking},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {64},
	year = {2004},
	month = {Jan},
	pages = {237-240},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {Our objectives were to investigate how a cow model, "Molly", deals with once-a-day milking and to use "Molly" in a Whole Farm Model to explore farm systems where once-a-day milking might produce results on a per hectare basis comparable to twice-a-day milking. We compared our model outputs to observed data from a Milking Frequency trial run by Dexcel at a research farm in Taranaki. Changing the rate constants for milk removal and degradation of the lactation hormone complex in "Molly" resulted in the model expressing the acute and chronic effects of once-a-day milking. The once-a-day cow model fed ad lib seasonal grass pasture showed a decrease in milksolids yield (kg/cow) of 31\% in Friesians compared to the observed 28\%. When we used .Molly. in the Whole Farm Model it showed that farm performance with once-a-day milking was 1135 kg milksolids/ha when a Friesian herd was stocked at 7\% higher and their lactation was extended by 14 days compared to a twice-a-day herd (1132 kg milksolids/ha). We conclude that farm performance with once-a-day milking is strongly dependent on selecting cows with higher lactational persistence under once-a-day milking and managing for extended lactations. },
	issn = {1176-5283},
	author = {Beukes PC and Thorrold BS and Wastney ME and Palliser CC and Clark DA}
}
