A statistical evaluation of associations between reproductive performance and milk composition and animal factors on grazing dairy cows in two New Zealand dairy farms

Author(s):  
LX Rodriguez-Cutzal ◽  
JL Burke ◽  
M Correa-Luna ◽  
N Lopez-Villalobos
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.


2017 ◽  
Vol 100 (5) ◽  
pp. 3805-3815 ◽  
Author(s):  
M.J. Giuliodori ◽  
M. Magnasco ◽  
R.P. Magnasco ◽  
I.M. Lacau-Mengido ◽  
R.L. de la Sota

2011 ◽  
Vol 94 (10) ◽  
pp. 4984-4996 ◽  
Author(s):  
E.S. Ribeiro ◽  
R.L.A. Cerri ◽  
R.S. Bisinotto ◽  
F.S. Lima ◽  
F.T. Silvestre ◽  
...  

Author(s):  
C.D. Waugh ◽  
D.A. Clark ◽  
S.L. Harris ◽  
E.R. Thom ◽  
P.J.A. Copeman ◽  
...  

The 1997-98 season has seen a marked increase in the amount of chicory planted on dairy farms in New Zealand. However, no New Zealand data are available for milk production from dairy cows grazing chicory. As part of a larger trial examining the effect of summer forage crops on milk production, Grasslands Puna chicory was compared with Barkant turnips. In January and March 1998, grazing trials were conducted at No.1 Dairy, Dairying Research Corporation using 60 lactating twin cows. In January, chicory and turnips were break-fed at a constant allowance (4 kg DM/cow/ day) to supplement pasture offered at 3 allowances (15, 27.5 and 40 kg DM/cow/day). In March, these crops were fed at 3 levels (0, 4 and 8 kg DM/cow/ day) to supplement pasture offered at a constant allowance of 25 kg DM/cow/day. Chicory and turnips gave similar milksolids (MS) responses of 40-41 g MS/kg DM offered in January. Milksolids responses in March were higher for turnips, 34 g MS/kg DM vs 32 g MS/kg DM from chicory. In January and March the size of the milksolids response declined with increasing allowance. This could be attributed to an increasing amount of substitution at higher allowances. Chicory produced between 8.8 and 13.8 t DM/ha from 4 October to 10 March, offering a high quality summer-autumn forage crop and improved milk production when supplemented with pasture. Keywords: chicory, Cichorium intybus, pasture allowance, dairy cows, milk production, forage crops, turnips, milksolids


2009 ◽  
Vol 2009 ◽  
pp. 12-12
Author(s):  
H S Gilmore ◽  
F J Young ◽  
R A Law ◽  
A R G Wylie ◽  
D C Patterson ◽  
...  

Poor fertility is a major problem on dairy farms. On-farm studies indicate than pregnancy rates to first service have declined from approximately 55% between 1975 and 1982 to 39% between 1995 and 1998 (Royal et al., 2000), illustrating a decline of approximately 1% per year during this period. The cause is multifactorial and influenced by many factors including genetics, management and nutrition. Previous studies have reported improved fertility through nutritional modification in early lactation (Gong et al., 2002). The aim of this study was to evaluate the effect of nutritional strategy in early lactation on reproductive performance.


2017 ◽  
Vol 185 ◽  
pp. 109-117
Author(s):  
N.A. Villa-Arcila ◽  
J. Sanchez ◽  
M.H. Ratto ◽  
J.C. Rodriguez-Lecompte ◽  
P.C. Duque-Madrid ◽  
...  

2003 ◽  
Vol 2003 ◽  
pp. 28-28
Author(s):  
L.R. McNaughton ◽  
G.A. Verkerk ◽  
T.J. Parkinson ◽  
B. Dow ◽  
K.A. Macdonald ◽  
...  

In pasture-based dairying systems it is important to maintain a 365-day calving interval, which requires that cows have a rapid resumption of postpartum ovulatory activity and high conception rates. The major form of infertility in New Zealand (NZ) dairy cows is an extended postpartum anovulatory interval (ppai; Macmillan, 2002), a problem that can be exacerbated by low body condition score (BCS) at calving (McDougall, 1995). Furthermore, Holstein cows, originating from North American genetic strains (Overseas; OS), which have been widely used in NZ in recent years, have longer intervals to first mating and conceive later than do NZ strains, suggesting a possible delay in the initiation of postpartum cyclicity (Harris and Winkleman, 2000). Worldwide, there is concern over an apparent decline in the fertility of Holstein-Friesian dairy cattle (Butler et al., 1995; Royal et al., 2000). The purpose of this trial was to determine whether there was a difference in ppai and BCS between NZ and OS Holstein Friesians that may affect reproductive performance.


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