Invited review: Accelerating mammary gland involution after drying-off in dairy cattle

Zhao, Xin; Ponchon, B.; Lanctôt, S.; Lacasse, P.

doi:10.3168/jds.2019-16377

Cited by 50 publications

(45 citation statements)

References 160 publications

(261 reference statements)

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“…The risk of mastitis may also increase when high-yielding cows are dried off (Enevoldsen and Sørensen, 1992;Gott et al, 2017) due to increased udder pressure (Bertulat et al, 2013). Zhao et al (2019) also offer other physiological mechanisms triggered by cessation of milk production, which suggest that high-producing cows may need a longer dry period for a complete renewal of their mammary gland. In practice, higher-yielding cows are sometimes given a shorter dry period length to have lower milk yields at dry-off.…”

Section: Effects Of Dry Period Length On Yields In the Subsequent Lactationmentioning

confidence: 99%

“…The dry period at the end of gestation is important for involution and redevelopment of mammary epithelial cells to prepare the mammary gland for the upcoming lactating period (Capuco et al, 1997;Zhao et al, 2019). Consequently, a short or omitted dry period reduces milk yield in the subsequent lactation (Bachman and Schairer, 2003;van Knegsel et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

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Piecewise modeling of the associations between dry period length and milk, fat, and protein yield changes in the subsequent lactation

Pattamanont

Marcondes

Clay

et al. 2021

Journal of Dairy Science

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Our objective was to develop predictive models of 305-d mature-equivalent milk, fat, and protein yields in the subsequent lactation as continuous functions of the number of days dry (DD) in the current lactation. In this retrospective cohort study with field data, we obtained DHIA milk recording lactation records with the last DD in 2014 or 2015. Cows included had DD from 21 to 100 d. After editing, 1,030,141 records from cows in 7,044 herds remained. Three parity groups of adjacent (current, subsequent) lactations were constructed. We conducted all analyses by parity group and yield component. We first applied control models to pre-adjust the yields in the subsequent lactation for potentially confounding effects. Control models included the covariates mature-equivalent yield, days open, somatic cell score at 180 d pregnant, daily yield at 180 d pregnant, and a herd-season random effect, all observed in the current lactation. Days dry was not included. Second, we modeled residuals from control models with smooth piecewise regression models consisting of a simple linear, quadratic, and another simple linear equation depending on DD. Yield deviations were calculated as differences from predicted matureequivalent yield at 50 DD. For validation, predictions of yield deviations from piecewise models by DD were compared with predictions from local regression for the DHIA field records and yield deviations reported in 38 experimental and field studies found in the literature. Control models reduced the average root mean squared prediction error by approximately 21%. Yield deviations were increasingly more negative for DD shorter than 50 d, indicating lower yields in the subsequent lactation. For short DD, the decrease in 305-d matureequivalent milk yield ranged from 43 to 53 kg per DD.For mature-equivalent fat and protein yields, decreases were between 1.28 and 1.71 kg per DD, and 1.06 and 1.50 kg per DD, respectively. Yield deviations often were marginally positive and increasing for DD >50, so that the highest yield in the subsequent lactation was predicted for 100 DD. For long DD, the 305-d matureequivalent milk yield increased at most 4.18 kg per DD. Patterns in deviations for fat and protein yield were similar to those for milk yield deviations. Predictions from piecewise models and local regressions were very similar, which supports the chosen functional form of the piecewise models. Yield deviations from field studies in the literature typically were decreasing when DD were longer, likely because of insufficient control for confounding effects. In conclusion, piecewise models of mature-equivalent milk, fat, and protein yield deviations as continuous functions of DD fit the observed data well and may be useful for decision support on the optimal dry period length for individual cows.

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Section: Effects Of Dry Period Length On Yields In the Subsequent Lactationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Piecewise modeling of the associations between dry period length and milk, fat, and protein yield changes in the subsequent lactation

Pattamanont

Marcondes

Clay

et al. 2021

Journal of Dairy Science

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“…During regenerative involution, cell proliferation and apoptosis increase, and mammary growth occurs with considerable turnover of the MEC. There is considerable interest in management protocols that may be used to accelerate involution (Zhao et al, 2019), enhance mammary proliferation (Wall et al, 2005;Crawford et al, 2015;Bentley et al, 2015), and reduce the epigenetic effects of heat stress through appropriate cooling measures (Tao et al, 2019) during this critical phase of cell turnover and mammary growth. What diminished functions may be restored by cell turnover during lactation and regenerative involution?…”

Section: Cell Turnover Cell Damage and Cell Senescencementioning

confidence: 99%

Symposium review: Determinants of milk production: Understanding population dynamics in the bovine mammary epithelium

Capuco

Choudhary

2020

Journal of Dairy Science

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The mammary gland undergoes distinct periods of growth, development, and secretory activity. During bovine lactation, a gradual decrease in the number of mammary epithelial cells largely accounts for the decline in milk production with advancing lactation. The net decline in cell number (approx. 50%) is due to cell death but is simultaneously accompanied by cell renewal. Although the rate of cell proliferation is slow, by the end of lactation most cells in the gland were formed after calving. Typically milking is terminated when cows are in the final 2 mo of pregnancy. This causes regenerative involution, wherein extensive cell replacement and mammary growth occurs. We hypothesized that replacement of senescent secretory cells and progenitor cells during the dry period increases milk yield in the next lactation. Analysis of global gene expression revealed networks and canonical pathways during regenerative involution that support cell turnover and mammary growth, and reflect oxidative stress, mitochondrial dysfunction, and endoplasmic reticulum (ER) stress. Immune responses consistent with influx of neutrophils, macrophages, and lymphocytes, and processes that support mammary differentiation and lactogenesis were also evident. Data also suggest that replication of stem and progenitor cells occurs during the dry period. Relying on long-term retention of bromodeoxyuridine-labeled DNA, we identified putative bovine mammary stem cells. These label-retaining epithelial cells (LREC) are in low abundance within mammary epithelium (<1%), predominantly estrogen receptor-negative, and localized in a basal or suprabas-al layer of the epithelium. Analyses of gene expression in laser-microdissected LREC are consistent with the concept that LREC represent stem cells and progenitor cells, which differ in properties and location within the epithelial layer. We identified potential markers for these cells and have increased their number by infusing xanthosine through the teat canal of prepubertal heifers. Altering population dynamics of mammary stem and progenitor cells during the mammary cycle may be a means to increase efficiency of milk production.

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“…The first half of the dry period is marked by high levels of programmed cell death and extracellular matrix remodeling. The second half of the dry period is characterized by high levels of proliferation of mammary epithelial cells (MEC) in the glands in preparation for the ensuing lactation (Zhao et al, 2019). Mammary remodeling during the dry period is critical as the number and metabolic activity of MEC directly corresponds with the cow's milk production capacity (Knight, 2000), and dry period management and environmental factors, such as photoperiod and heat stress, are known to affect mammary development during this time (Collier et al, 2006;Dahl, 2008;Mabjeesh et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Chronic prepartum light-dark phase shifts in cattle disrupt circadian clocks, decrease insulin sensitivity and mammary development, and are associated with lower milk yield through 60 days postpartum

McCabe

Suárez-Trujillo

Teeple

et al. 2021

Journal of Dairy Science

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Invited review: Accelerating mammary gland involution after drying-off in dairy cattle

Cited by 50 publications

References 160 publications

Piecewise modeling of the associations between dry period length and milk, fat, and protein yield changes in the subsequent lactation

Piecewise modeling of the associations between dry period length and milk, fat, and protein yield changes in the subsequent lactation

Symposium review: Determinants of milk production: Understanding population dynamics in the bovine mammary epithelium

Chronic prepartum light-dark phase shifts in cattle disrupt circadian clocks, decrease insulin sensitivity and mammary development, and are associated with lower milk yield through 60 days postpartum

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