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Representative examples of the slick phenotype in Holsteins. Panel A shows a slick (left) and non-slick cow; a close up of the face of a slick cow is shown in panel B. Note the absence of long hairs on the poll. Shown in panels C and D are examples of the shaved areas of the rump of slick (C) and wild-type (D) cows. Color version available in the online PDF.
Source publication
The SLICK haplotype (http://omia.angis.org.au/OMIA001372/9913/) in cattle confers animals with a short and sleek hair coat. Originally identified in Senepol cattle, the gene has been introduced into Holsteins. The objectives of the current study were to determine (1) whether lactating Holsteins with the slick hair phenotype have superior ability fo...
Contexts in source publication
Context 1
... all DIM, the reduction in fat percentage in sum- mer compared with winter was 0.19% for slick cows and 0.13% for wild-type cows (Table 1). The reduction in percentage protein and percentage lactose during the summer was also greater for slick cows than for wild-type cows, with differences between genetic types occurring after ~5 to 10 DIM (Figures 10 and 11). For percentage lactose, the interaction also reflected that differences between summer and winter were reduced after about 35 to 40 DIM in slick cows and about 50 DIM in wild-type cows. ...
Context 2
... cell score was also affected by a 3-way inter- action (P < 0.0001): SCS was lower in summer than in winter for slick cows on some days but not others, whereas season had no effect in wild-type cows ( Figure 12). The reduction in SCS in summer compared with winter was 0.13% for slick cows and 0.05% for wild-type cows (Table 1). ...
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Citations
... Cattle with one or two copies of the PRLR SLICK1 mutation have short hair, which is due to prolactin's increased ability to suppress hair development (Littlejohn et al., 2014). A possible effect is that during HS, animals with the mutation's slick phenotype are better at controlling their body temperature (Landaeta-Hernández et al., 2011;Dikmen et al., 2014;Landaeta-Hernández et al., 2021). Moreover, Davis (2019) reported that higher body weights and lower hair coat grades (slicker hair covers) have been associated with elevated prolactin levels. ...
... For instance, a slick mutation in the prolactin receptor gene (PRLR) identified in Senepol cattle has been incorporated into other dairy breeds in regions like Puerto Rico, Florida, and New Zealand. Studies later confirmed that Florida Holsteins carrying the slick phenotype showed lower rectal and vaginal temperatures and reduced respiration rates under heat stress compared to Holsteins lacking this phenotype [18]. Similarly, if other mutations conferring thermotolerance are found, either at the whole-animal or cellular level, it will open up new possibilities for employing genetic interventions to mitigate the effects of heat stress. ...
... In addition, as mentioned previously, the "slick" prolactin receptor gene (PRLR) mutation first observed in Senepol cattle has been integrated into Holstein dairy cattle to improve thermotolerance. Studies show these Holsteins maintain lower core body temperatures and respiration rates under heat stress, enhancing survival and productivity in tropical environments [18]. This selection process is further streamlined by marker-assisted selection (MAS), which enables breeders to focus on specific resilience markers. ...
The livestock sector, essential for maintaining food supply and security, encounters numerous obstacles as a result of climate change. Rising global populations exacerbate competition for natural resources, affecting feed quality and availability, heightening livestock disease risks, increasing heat stress, and contributing to biodiversity loss. Although various management and dietary interventions exist to alleviate these impacts, they often offer only short-lived solutions. We must take a more comprehensive approach to understanding how animals adapt to and endure their environments. One such approach is quantifying transcriptomes under different environments, which can uncover underlying pathways essential for livestock adaptation. This review explores the progress and techniques in studies that apply gene expression analysis to livestock production systems, focusing on their adaptation to climate change. We also attempt to identify various biomarkers and transcriptomic differences between species and pure/crossbred animals. Looking ahead, integrating emerging technologies such as spatialomics could further accelerate genetic improvements, enabling more thermoresilient and productive livestock in response to future climate fluctuations. Ultimately, insights from these studies will help optimize livestock production systems by identifying thermoresilient/desired animals for use in precise breeding programs to counter climate change.
... Cows were fed individually the same diet as a TMR once daily (1600 h) throughout the experiment in a Calan Broadbent feeding system (American Calan Inc., Northwood, NH, USA (NRC, 1971). The vaginal temperature was measured using an iButton (Mouser Electronics, Mansfield, TX) attached to a blank (progesterone-free) intravaginal implant (CIDR -Zoetis Animal Health), as described by Dikmen et al. (2014) and Kaufman et al. (2018), every 5 min for 4 consecutive d each week for all cows. ...
... inheritance of a single allele results in animals with the slick phenotype and increased ability to regulate body temperature during heat stress (Olson et al. 2003;Dikmen et al. 2008Dikmen et al. , 2014Sosa et al. 2022;Contreras-Correa et al. 2024). ...
... The approach was to produce females from many generations of backcrossing that would be Holstein apart from the presence of the SLICK1 allele of PRLR. Indeed, UF Holsteins inheriting the SLICK1 allele of PRLR exhibit superior ability to regulate body temperature during heat stress (Dikmen et al. 2008(Dikmen et al. , 2014Sosa et al. 2022) and with reduced milk yield depression in summer (Dikmen et al. 2014). The introgression of the SLICK1 allele not only exemplifies the potential benefit of targeted genetic interventions in improving animal welfare and productivity but also highlights the broader implications for sustainable livestock management in the face of global climate change. ...
... The approach was to produce females from many generations of backcrossing that would be Holstein apart from the presence of the SLICK1 allele of PRLR. Indeed, UF Holsteins inheriting the SLICK1 allele of PRLR exhibit superior ability to regulate body temperature during heat stress (Dikmen et al. 2008(Dikmen et al. , 2014Sosa et al. 2022) and with reduced milk yield depression in summer (Dikmen et al. 2014). The introgression of the SLICK1 allele not only exemplifies the potential benefit of targeted genetic interventions in improving animal welfare and productivity but also highlights the broader implications for sustainable livestock management in the face of global climate change. ...
This study evaluated the effectiveness of genetic introgression of the SLICK1 allele derived from Senepol cattle into the Holstein breed to enhance thermotolerance. The SLICK1 allele, located in PRLR gene, confers a short and sleek coat that is inherited as a simple dominant phenotype. Approximately 40 years ago, the University of Florida initiated efforts to introgress this allele into the Holstein population. Here we tracked the introgression of the SLICK1 allele using a medium-density genotyping array and a reference population of both breeds (50 Holstein, 46 Senepol). Among the 31 SLICK1+ Holsteins, there was 15.25% ± 11.11% (mean ± SD) Senepol ancestry on BTA20. Holsteins at the University of Florida descended from slick matings that did not inherit the SLICK1 allele (n=9) exhibited no Senepol ancestry. A secondary introgression of Senepol genetics in SLICK1+ animals was found on BTA4, spanning 54 markers and 15 genes, with 26.67% Senepol ancestry. This region, previously linked to heat stress adaptation, suggests that the introgression extends beyond the SLICK1 allele to incorporate additional beneficial genetics for thermal stress adaptation. These findings indicate that deliberate introgression of the SLICK1 allele enhances specific traits and potentially introduces other adaptive genetic variations. The study demonstrates the successful use of genetic interventions to improve livestock resilience against environmental challenges without significantly disrupting the recipient breed's genetic structure. The introgression of the SLICK1 allele serves as a model for breeding programs aimed at optimizing animal welfare and productivity in the face of global climate change while maintaining breed integrity.
... Thus, hair coat characteristics are important factors determining heat dissipation. Hair thickness may act as an insulating layer to diminish evaporation ( Dikmen et al. 2014 ). Criollo cattle breeds are characterized by having slick hair coats, which has been related to their heat stress resistance ( Olson et al. 2003 ). ...
... Even the FDA Risk Assessment points out that: "The IGA is the equivalent to the naturally occurring slick mutations that occur in several breeds of conventionally raised cattle where they likely developed as an adaptation to being raised in tropical or subtropical environments" ([1], p. 1). A similar variant was originally identified in the Senepol breed on the Caribbean Island of St. Croix [37]. It has also already been possible to transmit this special trait through conventional breeding, as has been the case with the 6 Page 6 of 15 ...
... Holstein breed [37]. Although the variant obtained via CRISPR-Cas9 differs in terms of its genomic sequence, it is similar in its phenotypic characteristics ...
... What benefits are there for cattle from a short and sleek (SLICK) coat of hair coat of the kind that follows from the genetic modification? Research -conducted on cattle with a naturally occurring SLICK variant, not calves with the IGA developed by Acceli-gen™ -demonstrated that SLICK cattle have an improved ability to cope with heat in comparison with their non-SLICK counterparts [37][38][39]. One test was carried out at the University of Florida and involved Holstein cattle. ...
In March 2022 the US Food and Drug Administration (FDA) published a risk assessment of a recent animal gene editing proposal submitted by Acceligen™. The proposal concerned the possibility of changing the cattle genome to obtain a slicker, shorter hair coat. Using CRISPR-Cas9 it was possible to introduce an intentional genomic alteration (IGA) to the prolactin receptor gene (PRLR), thereby producing PRLR-SLICK cattle. The goal was to diminish heat stress in the cattle by enhancing their heat-tolerance. With regard to unintended alterations (i.e., off-target effects), the FDA stated that the IGA posed a low, but still present, risk to animal safety. The aim of this article is to present some initial insights into the welfare issues raised by PRLR-SLICK cattle by addressing the question: Do SLICK cattle have better welfare than non-SLICK cattle when exposed to heat stress? Two potential welfare concerns are examined. The first is pleiotropy, an issue that arises when one gene affects multiple traits. Given the pleiotropic nature of prolactin, it has been suggested that the IGA for SLICK cattle may also affect their hepatic and other functions. The second concern relates not primarily to direct effects on cattle health, but rather to the indirect risk that this more heat-tolerant animal would just be used in the livestock sector under farming conditions that are such that the net welfare improvement would be non-existent.
... Collectively, these mutations are called slick mutations because animals inheriting either one or two copies of the mutation exhibit a sleek, short hair coat. 7,10,11 One function of prolactin is to inhibit hair growth 7 so slick cattle function as if signaling by prolactin is enhanced, at least concerning hair growth. Cattle inheriting one slick allele of PRLR exhibited superior ability to regulate body temperature and produce milk during heat stress. ...
... Cattle inheriting one slick allele of PRLR exhibited superior ability to regulate body temperature and produce milk during heat stress. [10][11][12][13] Here we demonstrate the use of gene editing techniques to introduce novel variants into PRLR that result in cattle with a slick phenotype. The variants were introduced into cattle of two breeds originating from Northern Europe that are both sensitive to heat stress and important globally for beef (Angus) or dairy production (Jersey). ...
... Vaginal temperature was measured using an iButton 1922 L (Maxim Integrated, San Jose, California, USA) as previously described. 11 Each iButton was set to measure in 15 min intervals for 5 days and set to 0.0625°C accuracy and placed inside of a blank (i.e., no progesterone) EASY-BREED CIDR device (Zoetis, Kalamazoo, MI, USA). The iButton-CIDR assembly was placed in the vagina for 5 days, with recording from 1630 H on day 0 until 1600 H on day 5. Animals moved freely in their pastures during data recording. ...
Global warming is a major challenge to the sustainable and humane production of food because of the increased risk of livestock to heat stress. Here, the example of the prolactin receptor (PRLR) gene is used to demonstrate how gene editing can increase the resistance of cattle to heat stress by the introduction of mutations conferring thermotolerance. Several cattle populations in South and Central America possess natural mutations in PRLR that result in affected animals having short hair and being thermotolerant. CRISPR/Cas9 technology was used to introduce variants of PRLR in two thermosensitive breeds of cattle – Angus and Jersey. Gene‐edited animals exhibited superior ability to regulate vaginal temperature (heifers) and rectal temperature (bulls) compared to animals that were not gene‐edited. Moreover, gene‐edited animals exhibited superior growth characteristics and had larger scrotal circumference. There was no evidence for deleterious effects of the mutation on carcass characteristics or male reproductive function. These results indicate the potential for reducing heat stress in relevant environments to enhance cattle productivity.
... Hair coat status reveals cattle's health, metabolism, and productive performance. For instance, slick-haired Holstein cows exhibit better thermoregulation and lesser milk production declines in summer than non-slick ones (Dikmen et al., 2014). Additionally, the presence of the slick hair mutation helps counter fescue toxicosis effects and improves beef cattle heifers' reproduction (Poole et al., 2019). ...
Introduction
The hair coat status of cattle serves as an easily observed indicator of economic value in livestock production; however, the underlying mechanism remains largely unknown. Therefore, the objective of the current study was to determine differences in the intestinal microbiota and metabolome of cattle based on a division of with either slick and shining (SHC) or rough and dull (MHC) hair coat in Simmental cows.
Methods
Eight SHC and eight MHC late-pregnancy Simmental cows (with similar parities, body weights, and body conditions) were selected based on their hair coat status, and blood samples (plasma) from coccygeal venipuncture and fecal samples from the rectum were collected. The intestinal microbiota (in the fecal samples) was characterized by employing 16S rRNA gene sequencing targeting the V3–V4 hypervariable region on the Illumina MiSeq PE300 platform, and plasma samples were subjected to LC–MS/MS-based metabolomics with Progenesis QI 2.3. Plasma macromolecular metabolites were examined for differences in the metabolism of lipids, proteins, mineral elements, and hormones.
Results
Notable differences between the SHC and MHC groups related to host hair coat status were observed in the host metabolome and intestinal microbiota (P < 0.05). The host metabolome was enriched in histidine metabolism, cysteine and methionine metabolism, and purine metabolism in the SHC group, and the intestinal microbiota were also enriched in histidine metabolism (P < 0.05). In the MHC group, the symbiotic relationship transitioned from cooperation to competition in the MHC group, and an uncoupling effect was present in the microbe–metabolite association of intestine microbiota–host interactions. The hubs mediating the relationships between intestinal microbiota and plasma metabolites were the intestinal bacterial genus g__norank_f__Eubacterium_coprostanoligenes_group, plasma inosine, triiodothyronine, and phosphorus, which could be used to differentiate cows’ hair coat status (P < 0.05).
Conclusion
Overall, the present study identified the relationships between the features of the intestinal microbiota and host hair coat status, thereby providing evidence and a new direction (intestine microbiota–host interplay) for future studies aimed at understanding the hair coat status of cattle.
... Of particular interest for understanding how convergent evolution can act in livestock populations is the existence of several different PRLR mutations that can produce the 'slick' phenotype in Criollo cattle [73]. Mutations in the bovine PRLR gene can have major effects on the length and the structure of hair coats providing improved thermotolerance and concomitant increases in fertility and milk yields in cattle populations that inhabit dry and tropical conditions [18,69,74]. In addition, it has been shown that these mutations can act pleiotropically and cause other physiological changes [75]. ...
Criollo cattle, the descendants of animals brought by Iberian colonists to the Americas, have been the subject of natural and human-mediated selection in novel tropical agroecological zones for centuries. Consequently, these breeds have evolved distinct characteristics such as resistance to diseases and exceptional heat tolerance. In addition to European taurine (Bos taurus) ancestry, it has been proposed that gene flow from African taurine and Asian indicine (Bos indicus) cattle has shaped the ancestry of Criollo cattle. In this study, we analysed Criollo breeds from Colombia and Venezuela using whole-genome sequencing (WGS) and single-nucleotide polymorphism (SNP) array data to examine population structure and admixture at high resolution. Analysis of genetic structure and ancestry components provided evidence for African taurine and Asian indicine admixture in Criollo cattle. In addition, using WGS data, we detected selection signatures associated with a myriad of adaptive traits, revealing genes linked to thermotolerance, reproduction, fertility, immunity and distinct coat and skin coloration traits. This study underscores the remarkable adaptability of Criollo cattle and highlights the genetic richness and potential of these breeds in the face of climate change, habitat flux and disease challenges. Further research is warranted to leverage these findings for more effective and sustainable cattle breeding programmes.
... Skin color and hair density also can influence the measurements as hair functions as an insulator and reduces infrared radiation output [19], [22]. Slick hair can, indeed, have an impact on IRT measurements, despite the fact that it has been shown that animals with slick hair have better thermoregulatory capacities, perhaps as a result of higher perspiration [23] As a result, IRT at a hairless skin region, such as ocular bulb or muzzle area, often yields a greater IRT range than a hairy one [24]. Due to the higher emissivity in visible wavelengths of black hair and consequent higher IRT detected in thermograms, cattle with black hair absorb and emit more solar energy than those with white hair [25]. ...
The most widely used predictor to assess the incidence of thermal stress in livestock is THI, the temperature humidity index. However, it is an indicator that disregards the individual animal and the specific farm conditions. This review aims to list and summarize other thermal stress predictor factors, by using non-invasive and cost-effective strategies, in particular with the aid of Precision Livestock Farming technologies. When it comes to dairy animals the metabolic load is already increased by milk production, so the effect of heat stress can exacerbate the overall welfare of the cow. Therefore, the animals enact copying mechanisms that may result in physiological, behavioral and productive alterations. Those animal-based parameters can be used as early predictors of heat stress, allowing the farmer to collect real time data and address the condition operating management strategies in order to prevent further detrimental effect on the performance and consequent economic losses.
