Selection scheme designs for dairy cattle milked once daily in New Zealand: a deterministic approach

Lembeye, F; López‐Villalobos, N.; Burke, J. L.; Davis, Steven R.

doi:10.1080/00288233.2020.1852580

Cited by 3 publications

(9 citation statements)

References 27 publications

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“…The results presented in Table 4 indicate that genetic gain for MY is 25% smaller as compared with a simulation carried out in New Zealand by Sneddon et al (2016), however, milk solids composition is 30-55% greater. Compared with another study under pastoral systems (Lembeye et al, 2021), predicted genetic response for FY and PY agree with simulations for the once-daily milking population in New Zealand only when bulls were tested in twice-daily milking systems. In the simulation for the PT-scheme, the genetic response for milk solids is smaller in Lembeye et al (2021) as compared with results shown in Table 4, and only similar for MY when udder-related type traits are included in the selection objectives.…”

Section: Discussionsupporting

confidence: 58%

“…Compared with another study under pastoral systems (Lembeye et al, 2021), predicted genetic response for FY and PY agree with simulations for the once-daily milking population in New Zealand only when bulls were tested in twice-daily milking systems. In the simulation for the PT-scheme, the genetic response for milk solids is smaller in Lembeye et al (2021) as compared with results shown in Table 4, and only similar for MY when udder-related type traits are included in the selection objectives. These differences result from different genetic parameters (h 2 and genetic variances) evaluated for the selected population (Chilean dairy cattle, Overo Colorado breed).…”

Section: Discussionsupporting

confidence: 58%

“…From this simulation study, we can expect a small reduction in SCS and a small increment in longevity. For longevity, the direction of the selection response agrees with Sneddon et al (2016) and Lembeye et al (2021), however, this finding cannot be directly compared with those studies since the genetic variance used in this simulation was measured in a score scale, while in Sneddon et al (2016) and Lembeye et al (2021) it was measured in days. There are no reported genetic parameters for longevity in Chilean dairy cattle, and this trait is not considered in VEL.…”

Section: Discussionmentioning

confidence: 62%

“…Each bull was assumed to be evaluated based on the performance of 85 daughters (Spelman and Garrick, 1997). The proportions of selected bulls are greater than those selected in New Zealand (Sneddon et al ., 2016), since for small populations (as deemed for the Chilean dairy cattle industry), it would be required to increase the proportion of bulls selected to avoid inbreeding (Lembeye et al ., 2021).…”

Section: Methodsmentioning

confidence: 99%

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Potential response from selection schemes based on progeny testing and genomic selection for the Chilean dairy cattle under pastoral systems: a deterministic simulation

Lembeye¹,

López‐Villalobos

Uribe

2022

Journal of Dairy Research

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Recently, a selection index called Valor Económico Lechero (VEL) was developed for Chilean dairy cattle under pasture. However, a specific selection scheme has not yet been implemented. This study aimed to estimate genetic progress from selection on the VEL selection index based on selection schemes using progeny testing (PT) and genomic selection (GS). Under a PT-scheme, estimated genetic progress was 41.50, 3.44, and 2.33 kg/year for milk, fat, and protein yield, respectively. The realised genetic gain takes eight-year after the PT-scheme implementation, which may be a disincentive for implementing a PT-scheme, suggesting that importing frozen semen of proven bulls could be a preferred alternative. In this case, an option may be to conduct the genetic evaluation of those bulls using their progeny in Chile for the traits included in VEL selection index. In the case of implementing a specific selection scheme, compared to PT, a more profitable alternative might be the implementation of a GS-scheme, that would result in a faster genetic gain in the aggregate breeding value or merit for all the traits included in the selection objective (0.323–0.371 vs. 0.194 σg/year).

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Section: Discussionsupporting

confidence: 58%

Section: Discussionsupporting

confidence: 58%

Section: Discussionmentioning

confidence: 62%

Section: Methodsmentioning

confidence: 99%

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Potential response from selection schemes based on progeny testing and genomic selection for the Chilean dairy cattle under pastoral systems: a deterministic simulation

Lembeye¹,

López‐Villalobos

Uribe

2022

Journal of Dairy Research

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“…For some time, there was a policy to abort cows that were slow to conceive. Thankfully, this policy has largely been abandoned, reflecting a selection policy designed to place greater emphasis on fertility (Lembeye et al, 2021).…”

Section: Opportunities For Changementioning

confidence: 99%

Green Milk From Contented Cows: Is It Possible?

Webster

2021

Front. Anim. Sci.

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The dairy industry is open to criticism on several fronts: obesity and ill health among the affluent, high demand for crops that could be consumed more sustainably and more equitably by ourselves, environmental damage and climate change, and abuse of animal welfare through production diseases and denial of normal patterns of behaviour. All these criticisms are valid. It is necessary therefore to examine in depth the nature and extent of specific problems to see which, if any, are inevitable, which can be mitigated and which can be avoided altogether. Dairy cattle, like all ruminants, can be sustained wholly, or in part on complementary feeds; grasses and crop residues that cannot be fed directly to humans. Fed appropriate diets dairy cows can produce more energy and protein for human consumption than they consume. The greenhouse gas, methane is an inevitable consequence of rumen fermentation. High yielding cows in confinement produce less methane per litre of milk. There is some scope for reducing methane production through manipulation of rumen fermentation but the impact is likely to be small. The most serious welfare abuses can be linked to genetic and management strategies designed to maximise milk yield from individual cows. These manifest in production diseases and metabolic exhaustion, both leading to premature culling. All these problems; too much milk, too much food waste, too much methane, too many stressed cows, are matters of degree. The poison is in the dose. Thus, solutions will not come from radical advances in biological science but public and political exercises in moderation.

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Recent advances in grazed pasture-based dairy science

Clough

2021

New Zealand Journal of Agricultural Research

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Selection scheme designs for dairy cattle milked once daily in New Zealand: a deterministic approach

Cited by 3 publications

References 27 publications

Potential response from selection schemes based on progeny testing and genomic selection for the Chilean dairy cattle under pastoral systems: a deterministic simulation

Potential response from selection schemes based on progeny testing and genomic selection for the Chilean dairy cattle under pastoral systems: a deterministic simulation

Green Milk From Contented Cows: Is It Possible?

Recent advances in grazed pasture-based dairy science

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