Effects of shade provision on the behaviour, body temperature and milk production of grazing dairy cows during a New Zealand summer

2008 ◽  
Vol 51 (2) ◽  
pp. 99-105 ◽  
Author(s):  
A. D. Fisher ◽  
N. Roberts ◽  
S. J. Bluett ◽  
G. A. Verkerk ◽  
L. R. Matthews
Author(s):  
G.P. Cosgrove ◽  
J.L. Burke ◽  
A.F. Death ◽  
M.J. Hickey ◽  
D. Pacheco ◽  
...  

An elevated concentration of water soluble carbohydrate (WSC) in grasses may increase the availability of readily degradable energy, increase milk production and improve the efficiency of nitrogen utilisation. Two ryegrasses with elevated WSC, a tetraploid Italian (IRG) and a diploid perennial selected for higher WSC (HSG), were compared against a standard diploid perennial (STG) during spring 2004 and 2005, and autumn 2006 and 2007. Groups of cows (n=20) grazed each grass type for periods of 6 weeks in spring and 2 weeks in autumn. During spring, the 'high' WSC grasses were 20-40 g/kg DM higher in concentration of WSC than the standard (P


Genes ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 456
Author(s):  
Hewa Bahithige Pavithra Chathurangi Ariyarathne ◽  
Martin Correa-Luna ◽  
Hugh Thomas Blair ◽  
Dorian John Garrick ◽  
Nicolas Lopez-Villalobos

The objective of this study was to identify genomic regions associated with milk fat percentage (FP), crude protein percentage (CPP), urea concentration (MU) and efficiency of crude protein utilization (ECPU: ratio between crude protein yield in milk and dietary crude protein intake) using grazing, mixed-breed, dairy cows in New Zealand. Phenotypes from 634 Holstein Friesian, Jersey or crossbred cows were obtained from two herds at Massey University. A subset of 490 of these cows was genotyped using Bovine Illumina 50K SNP-chips. Two genome-wise association approaches were used, a single-locus model fitted to data from 490 cows and a single-step Bayes C model fitted to data from all 634 cows. The single-locus analysis was performed with the Efficient Mixed-Model Association eXpedited model as implemented in the SVS package. Single nucleotide polymorphisms (SNPs) with genome-wide association p-values ≤ 1.11 × 10−6 were considered as putative quantitative trait loci (QTL). The Bayes C analysis was performed with the JWAS package and 1-Mb genomic windows containing SNPs that explained > 0.37% of the genetic variance were considered as putative QTL. Candidate genes within 100 kb from the identified SNPs in single-locus GWAS or the 1-Mb windows were identified using gene ontology, as implemented in the Ensembl Genome Browser. The genes detected in association with FP (MGST1, DGAT1, CEBPD, SLC52A2, GPAT4, and ACOX3) and CPP (DGAT1, CSN1S1, GOSR2, HERC6, and IGF1R) were identified as candidates. Gene ontology revealed six novel candidate genes (GMDS, E2F7, SIAH1, SLC24A4, LGMN, and ASS1) significantly associated with MU whose functions were in protein catabolism, urea cycle, ion transportation and N excretion. One novel candidate gene was identified in association with ECPU (MAP3K1) that is involved in post-transcriptional modification of proteins. The findings should be validated using a larger population of New Zealand grazing dairy cows.


Author(s):  
C.S. Mayne ◽  
S.C.P. Woodcock ◽  
A.J. Clements

Buffer-feeding of grazing dairy cows, by allowing cows access to forage for a few hours each day, has been widely advocated as a means of maintaining high animal performance whilst enabling efficient sward utilization. However, in practice, responses to buffer-feeding with January/February calving cows have been extremely variable. The objective of this study was to examine if part of the variability in response could be explained by differences in the level of nutrition during the winter feed period.


1958 ◽  
Vol 1958 ◽  
pp. 3-12 ◽  
Author(s):  
J. L. Corbett

Calculations based on conventional feeding standards suggest that cows grazing well-managed pasture are frequently consuming excessive quantities of protein in relation to their requirements and to the starch equivalent consumed. They also suggest that milk production from potentially high-yielding cows is limited primarily by the supply of dietary energy. This paper describes two experiments on the effects of low-protein supplements on the performance of grazing dairy cows and reports the main results on yield and composition of milk and herbage consumption. Full details and results, and some other aspects of the experiments, are being reported elsewhere.


2020 ◽  
Vol 60 (1) ◽  
pp. 143 ◽  
Author(s):  
Bríd McClearn ◽  
Trevor Gilliland ◽  
Clare Guy ◽  
Michael Dineen ◽  
Fergal Coughlan ◽  
...  

Grazed grass is considered the cheapest feed available for dairy cows in temperate regions, and to maximise profits, dairy farmers must utilise this high-quality feed where possible. Recent research has reported that including white clover (Trifolium repens L.) in grass swards can have a positive effect on milk production. The aim of the present study was to quantify the effect of tetraploid and diploid perennial ryegrass (Lolium perenne L.; PRG) swards sown with and without white clover on the milk production of grazing dairy cows. Four grazing treatments were used for the study; tetraploid-only PRG swards, diploid-only PRG swards, tetraploid PRG with white clover swards and diploid PRG with white clover swards. Thirty cows were assigned to each treatment and swards were rotationally grazed at a stocking rate of 2.75 cows/ha and a nitrogen-fertiliser application rate of 250 kg/ha annually. There was no significant effect of ploidy on milk production. Over the present 4-year study, cows grazing the PRG–white clover treatments had greater milk yields (+597 kg/cow.year) and milk-solid yield (+48 kg/cow.year) than cows grazing the PRG-only treatments. This significant increase in milk production suggests that the inclusion of white clover in grazing systems can be effectively used to increase milk production of grazing dairy cows.


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