Heifers with positive genetic merit for fertility traits reach puberty earlier and have a greater pregnancy rate than heifers with negative genetic merit for fertility traits

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dc.citation.issue3
dc.citation.volume104
dc.contributor.authorMeier S
dc.contributor.authorMcNaughton LR
dc.contributor.authorHandcock R
dc.contributor.authorAmer PR
dc.contributor.authorBeatson PR
dc.contributor.authorBryant JR
dc.contributor.authorDodds KG
dc.contributor.authorSpelman R
dc.contributor.authorRoche JR
dc.contributor.authorBurke CR
dc.coverage.spatialUnited States
dc.date.accessioned2024-03-21T00:24:25Z
dc.date.accessioned2024-07-25T06:37:42Z
dc.date.available2021-01-15
dc.date.available2024-03-21T00:24:25Z
dc.date.available2024-07-25T06:37:42Z
dc.date.issued2021-03
dc.description.abstractThis study investigated the hypothesis that dairy heifers divergent in genetic merit for fertility traits differ in the age of puberty and reproductive performance. New Zealand's fertility breeding value (FertBV) is the proportion of a sire's daughters expected to calve in the first 42 d of the seasonal calving period. We used the New Zealand national dairy database to identify and select Holstein-Friesian dams with either positive (POS, +5 FertBV, n = 1,334) or negative FertBV (NEG, -5% FertBV, n = 1,662) for insemination with semen from POS or NEG FertBV sires, respectively. The resulting POS and NEG heifers were predicted to have a difference in average FertBV of 10 percentage points. We enrolled 640 heifer calves (POS, n = 324; NEG, n = 316) at 9 d ± 5.4 d (± standard deviation; SD) for the POS calves and 8 d ± 4.4 d old for the NEG calves. Of these, 275 POS and 248 NEG heifers were DNA parent verified and retained for further study. The average FertBV was +5.0% (SD = 0.74) and -5.1% (SD = 1.36) for POS and NEG groups, respectively. Heifers were reared at 2 successive facilities as follows: (1) calf rearing (enrollment to ∼13 wk of age) and (2) grazier, after 13 wk until 22 mo of age. All heifers wore a collar with an activity sensor to monitor estrus events starting at 8 mo of age, and we collected weekly blood samples when individual heifers reached 190 kg of body weight (BW) to measure plasma progesterone concentrations. Puberty was characterized by plasma progesterone concentrations >1 ng/mL in at least 2 of 3 successive weeks. Date of puberty was defined when the first of these samples was >1 ng/mL. Heifers were seasonally bred for 98 d starting at ∼14 mo of age. Transrectal ultrasound was used to confirm pregnancy and combined with activity data to estimate breeding and pregnancy dates. We measured BW every 2 wk, and body condition and stature at 6, 9, 12, and 15 mo of age. The significant FertBV by day interaction for BW was such that the NEG heifers had increasingly greater BW with age. This difference was mirrored with the significant FertBV by month interaction for average daily gain, with the NEG heifers having a greater average daily gain between 9 and 18 mo of age. There was no difference in heifer stature between the POS and NEG heifers. The POS heifers were younger and lighter at puberty, and were at a lesser mature BW, compared with the NEG heifers. As a result, 94 ± 1.6% of the POS and 82 ± 3.2% of the NEG heifers had reached puberty at the start of breeding. The POS heifers were 20% and 11% more likely to be pregnant after 21 d and 42 d of breeding than NEG heifers (relative risk = 1.20, 95% confidence interval of 1.03-1.34; relative risk = 1.11, 95% confidence interval of 1.01-1.16). Results from this experiment support an association between extremes in genetic merit for fertility base on cow traits and heifer reproduction. Our results indicate that heifer puberty and pregnancy rates are affected by genetic merit for fertility traits, and these may be useful phenotypes for genetic selection.
dc.description.confidentialfalse
dc.format.pagination3707-3721
dc.identifier.author-urlhttps://www.ncbi.nlm.nih.gov/pubmed/33455798
dc.identifier.citationMeier S, McNaughton LR, Handcock R, Amer PR, Beatson PR, Bryant JR, Dodds KG, Spelman R, Roche JR, Burke CR. (2021). Heifers with positive genetic merit for fertility traits reach puberty earlier and have a greater pregnancy rate than heifers with negative genetic merit for fertility traits.. J Dairy Sci. 104. 3. (pp. 3707-3721).
dc.identifier.doi10.3168/jds.2020-19155
dc.identifier.eissn1525-3198
dc.identifier.elements-typejournal-article
dc.identifier.issn0022-0302
dc.identifier.piiS0022-0302(21)00031-X
dc.identifier.urihttps://mro.massey.ac.nz/handle/10179/70574
dc.languageeng
dc.publisherElsevier Inc on behalf of the American Dairy Science Association
dc.publisher.urihttps://www.sciencedirect.com/science/article/pii/S002203022100031X
dc.relation.isPartOfJ Dairy Sci
dc.rights(c) 2021 The Author/s
dc.rightsCC BY-NC-ND 4.0
dc.rights.urihttps://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subjectfertility
dc.subjectgenetic
dc.subjectheifer
dc.subjectpregnancy
dc.subjectpuberty
dc.subjectAnimals
dc.subjectCattle
dc.subjectFemale
dc.subjectFertility
dc.subjectNew Zealand
dc.subjectPhenotype
dc.subjectPregnancy
dc.subjectPregnancy Rate
dc.subjectReproduction
dc.subjectSexual Maturation
dc.titleHeifers with positive genetic merit for fertility traits reach puberty earlier and have a greater pregnancy rate than heifers with negative genetic merit for fertility traits
dc.typeJournal article
pubs.elements-id444276
pubs.organisational-groupOther
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