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Topic:Lactation

Lactation in horses refers to the process by which mares produce milk to nourish their foals following birth. This physiological process involves the mammary glands, which undergo significant changes during pregnancy and after foaling to produce and secrete milk. The composition of equine milk includes essential nutrients, antibodies, and bioactive components that support the growth and immune function of the foal. The lactation period in horses typically lasts for several months, during which the mare's nutritional and health status can impact milk production and quality. This page compiles peer-reviewed research studies and scholarly articles that explore the biology, management, and nutritional aspects of lactation in horses, as well as its implications for foal development and mare health.
Dominant follicle and gonadotropin dynamics before ovulation in postpartum lactating mares.
Molecular reproduction and development    January 9, 2022   Volume 89, Issue 2 113-124 doi: 10.1002/mrd.23552
Gastal MO, Pastorello M, Godoi DB, Gastal EL.The aim of this study was to compare the dominant follicle (DF) and gonadotropin dynamics for 9 days before ovulation in postpartum lactating (PP Lactating) versus non-postpartum cycling (N-PP Cycling) mares. Every PP Lactating mare on the day of parturition was paired with a N-PP Cycling mare, and the data analyses considered the partum-ovulation interval (POI) and the postpartum interovulatory interval (PPIOI) in PP Lactating mares and two interovulatory intervals in N-PP Cycling mares. The results of the present study revealed several novel and unique aspects of DF development and FSH and L...
Composition and aptitude for cheese-making of milk from cows, buffaloes, goats, sheep, dromedary camels, and donkeys.
Journal of dairy science    December 23, 2021   Volume 105, Issue 3 2132-2152 doi: 10.3168/jds.2021-20961
Bittante G, Amalfitano N, Bergamaschi M, Patel N, Haddi ML, Benabid H, Pazzola M, Vacca GM, Tagliapietra F, Schiavon S.Bovines produce about 83% of the milk and dairy products consumed by humans worldwide, the rest represented by bubaline, caprine, ovine, camelid, and equine species, which are particularly important in areas of extensive pastoralism. Although milk is increasingly used for cheese production, the cheese-making efficiency of milk from the different species is not well known. This study compares the cheese-making ability of milk sampled from lactating females of the 6 dairy species in terms of milk composition, coagulation properties (using lactodynamography), curd-firming modeling, nutrients reco...
[Effects of oral manganese supplementation with different compounds on the manganese whole blood and serum concentrations of broodmares and their suckling foals].
Tierarztliche Praxis. Ausgabe G, Grosstiere/Nutztiere    December 3, 2021   Volume 49, Issue 6 392-402 doi: 10.1055/a-1656-2610
Theiner E, Weber C, Müller E, Venner M, Finkler-Schade C, Vervuert I.This study aimed to examine the effects of an oral supplementation on manganese (Mn) concentrations in the blood of lactating warm-blood broodmares. Furthermore, the potential relationship between Mn supply of the lactating mare and its suckling foal was investigated. Methods: During the 90-day trial, lactating mares were divided into 3 groups and daily received a daily dose of either a placebo (n = 11) or a Mn supplement of 560 mg Mn as Mn sulfate (n = 11) or Mn chelate (n = 11) in addition to the Mn intake from the basal ration (hay ad libitum, total mixed ration: Mn intake ~ 1...
Assessment of serum amyloid A concentrations and biochemical profiles in lactating jennies and newborn Ragusano donkey foals around parturition and one month after foaling in Sicily.
Reproduction in domestic animals = Zuchthygiene    November 29, 2021   Volume 57, Issue 3 262-268 doi: 10.1111/rda.14048
Bazzano M, Bonfili L, Eleuteri AM, Serri E, Scollo C, Yaosen Y, Tesei B, Laus F.A proper knowledge of biochemical parameters and inflammatory markers like serum amyloid A (SAA) is crucial in the monitoring of the first post-partum period in equids. Since no information is available on SAA for donkeys at this stage, 50 animals including jennies (n.10) and newborn foals (n.10) within 48 hr from foaling, and jennies (n.10) and foals (n.20) after 30 days from parturition were enrolled in the study to assess routine biochemical profile including SAA. Jennies showed higher alkaline phosphatase and lower bilirubins and cholesterol at 30 days of lactation compared to post-part...
Relationship between lactational performance and metabolic parameters of Mongolian native grazing mares.
Journal of equine science    September 6, 2021   Volume 32, Issue 3 91-98 doi: 10.1294/jes.32.91
Sandagdorj B, Baigalmaa T, Burenjargal S, Horiuchi M, Enkhdalai M, Bayanbat D, Janchiv D, Jamyandorj O, Ulzii-Orshikh P, Nyam-Osor P.Information regarding the lactational performance of mares in relation to metabolic parameters can help practitioners to manipulate animal rearing management for sustainable mare milk production. The aim of this study was to characterize the lactational performance of Mongolian native mares grazing on natural pastureland by revealing the seasonal effects on metabolic parameters. In this study, 8 multiparous mares were used. Milk yield and composition and serum metabolic parameters, such as alanine aminotransferase, aspartate aminotransferase (AST), glucose (GLU), triacylglycerol, total cholest...
Reproductive patterns and follicular waves in postpartum lactating versus non-postpartum cycling mares.
Journal of equine veterinary science    August 13, 2021   Volume 107 103732 doi: 10.1016/j.jevs.2021.103732
Gastal EL, Pastorello M, Godoi DB, Gastal MO.This comparative study between postpartum lactating (PP Lactating) and non-postpartum cycling (N-PP Cycling) mares aimed to characterize reproductive patterns, types and frequencies of follicular waves, corpus luteum and endometrial echotexture dynamics, and the influence of season and body condition. Mares from each group were paired considering the day of parturition of a PP Lactating mare. The partum-ovulation interval (POI) and the postpartum interovulatory interval (PPIOI) were evaluated for PP Lactating mares, and 2 IOIs were evaluated for N-PP Cycling mares. The following observations w...
Evaluation of key miRNAs during early pregnancy in Kazakh horse using RNA sequencing.
PeerJ    February 23, 2021   Volume 9 e10796 doi: 10.7717/peerj.10796
Liu L, Fang C, Sun Y, Liu W.miRNA has an important role in cell differentiation, biological development, and physiology. Milk production is an important quantitative trait in livestock and miRNA plays a role in the amount of milk produced. Methods: The role of regulatory miRNAs involved in equine milk production is not fully understood. We constructed two miRNA libraries for Kazakh horse milk production from higher-producing (H group) and lower-producing (L group) individuals, and used RNA-Seq technology to identify the differentially expressed miRNAs between the two milk phenotypes of Kazakh horses. Results: A total of ...
Transcriptome study underling difference of milk yield during peak lactation of Kazakh horse.
Journal of equine veterinary science    February 19, 2021   Volume 102 103424 doi: 10.1016/j.jevs.2021.103424
Yu X, Fang C, Liu L, Zhao X, Liu W, Cao H, Lv S.This study was designed to provide a basis for further understanding of the mechanism of lactation based on mRNA expression differences in milk fat between different milk yields in Kazakh horses. Total RNA was extracted from the milk fat during the peak of lactation period. A total of 310 differentially expressed genes (DEGs) were identified by comparative transcriptome analysis of the high-yield and low-yield group. These DEGs regulate lactation by participated in AMPK signaling pathway, FoxO signaling pathway, ErbB signaling pathway, VEGF signaling pathway. In addition, we performed quantita...
Comparative Analysis of Serum Mineral and Biochemical Parameter Profiles Between Late Pregnant and Early Lactating Jennies.
Journal of equine veterinary science    February 3, 2021   Volume 99 103401 doi: 10.1016/j.jevs.2021.103401
Liao Q, Li Z, Han Y, Deng L.The purpose of this study was to investigate the profile change of serum trace and major elements, and biochemical and hematological parameters in jennies during late pregnancy and early lactation. Twenty-five healthy Chinese Liaoxi jennies were used in late pregnancy and early lactation. Results showed that the levels of Fe, total protein (TP), and aspartate aminotransferase (AST) were highly variable interindividual among the jennies. Early lactating jennies showed significantly lower serum levels of K, Se, AST, total cholesterol (TC), and triglyceride than late pregnant jennies (P < .05)...
Grazing Mares on Pasture with Sycamore Maples: A Potential Threat to Suckling Foals and Food Safety through Milk Contamination.
Animals : an open access journal from MDPI    January 5, 2021   Volume 11, Issue 1 doi: 10.3390/ani11010087
Renaud B, François AC, Boemer F, Kruse C, Stern D, Piot A, Petitjean T, Gustin P, Votion DM.Equine atypical myopathy (AM) is seasonal intoxication resulting from the ingestion of seeds and seedlings of the sycamore maple (Acer pseudoplatanus) that contain toxins, among them, hypoglycin A (HGA). Literature mentions several cases of AM among gravid mares and in unweaned foals. The objective of this study was to determine whether HGA and/or its metabolite are present in milk from grazing mares exposed to sycamore maple trees as confirmed by detection of HGA and its metabolite in their blood. Four mare/foal couples were included in the study. Both HGA and its metabolite were detectable i...
Development and Pathology of the Equine Mammary Gland.
Journal of mammary gland biology and neoplasia    December 5, 2020   Volume 26, Issue 2 121-134 doi: 10.1007/s10911-020-09471-2
Hughes K.An understanding of the anatomy, histology, and development of the equine mammary gland underpins study of the pathology of diseases including galactorrhoea, agalactia, mastitis, and mammary tumour development. This review examines the prenatal development of the equine mammary gland and the striking degree to which the tissue undergoes postnatal development associated with the reproductive cycle. The gland is characterised by epithelial structures arranged in terminal duct lobular units, similar to those of the human breast, supported by distinct zones of intra- and interlobular collagenous s...
Relationships between blood and follicular fluid urea nitrogen concentrations and between blood urea nitrogen and embryo survival in mares.
Theriogenology    November 11, 2020   Volume 160 142-150 doi: 10.1016/j.theriogenology.2020.10.039
Boakari YL, El-Sheikh Ali H, Schnobrich M, Lofrumento K, Scoggin C, Bradecamp E, Scoggin K, Esteller-Vico A, Claes A, Lawrence L, Ball B.High blood urea nitrogen (BUN) concentration is linked to low fertility in cows and ewes; however, this relationship has not been reported in mares. The study characterized the relationship between BUN and follicular fluid urea nitrogen (FUN) during follicle growth (Experiment 1) and the impact of BUN from embryo donors on the pregnancy outcome of recipient mares (Experiment 2). In experiment one, follicular fluid and blood samples were collected from mares during diestrus with growing follicles and during estrus with pre-ovulatory follicles (n = 16 and 10 mares, respectively). In experiment...
Chemical composition and lipid profile of mare colostrum and milk of the quarter horse breed.
PloS one    September 14, 2020   Volume 15, Issue 9 e0238921 doi: 10.1371/journal.pone.0238921
Barreto ÍMLG, Urbano SA, Oliveira CAA, Macêdo CS, Borba LHF, Chags BME, Rangel AHN.The objective of this study was to characterize the chemical composition and lipid profile of colostrum and milk of purebred Quarter Horse mares. Thirty-four (34) purebred mares were selected, which were then separated into groups according to age, birth order and lactation stage. Colostrum samples were collected in the first six hours after delivery and milk samples from the 7th postpartum day, with intervals of 14 days until the end of lactation. The samples were refrigerated and sent to the Milk Laboratory of the University (Laboleite-UFRN), where they were analyzed for chemical composition...
Evaluation of jennies’ colostrum: IgG concentrations and absorption in the donkey foals. A preliminary study.
Heliyon    August 3, 2020   Volume 6, Issue 8 e04598 doi: 10.1016/j.heliyon.2020.e04598
Immunoglobulin type G (IgG) concentration both in jennies' colostrum and in serum of donkey foals are mostly unknown in the first 24 h after delivery. The aims of the present study were to evaluate the IgG concentrations of colostrum during the first 24 h of lactation of Amiata jennies, the absorption of colostrum and the weekly body weight gain of the donkey foals. IgG concentrations were assessed in the jennies' colostrum and in the serum of donkey foals. Colostrum was collected in 9 jennies ready after delivery, and at 6, 12, 24 h after foaling from both halves. Serum was collected at the s...
Donkey Feeding During Maintenance, Pregnancy, and Lactation: Effects on Body Weight, Milk Production, and Foal Growth.
Journal of equine veterinary science    May 22, 2020   Volume 91 103131 doi: 10.1016/j.jevs.2020.103131
Salari F, Licitra R, Altomonte I, Martini M.We evaluated the daily intake in donkeys during maintenance, late pregnancy, and early lactation. The growth curves of the foals in the first eight weeks of life and the milk production in lactating jennies were also investigated. Donkeys were separated into two groups: seven pregnant jennies (group 1: pregnant/lactating) and seven nonpregnant, nonlactating jennies (group 2). The groups were fed two different diets each. The feeding period for group 1 covered eight weeks before parturition and eight weeks postpartum. Group 2 was managed during the same time period (16 weeks). Diet 1 consisted...
Genes encoding equine β-lactoglobulin (LGB1 and LGB2): Polymorphism, expression, and impact on milk composition.
PloS one    April 22, 2020   Volume 15, Issue 4 e0232066 doi: 10.1371/journal.pone.0232066
Wodas L, Mackowski M, Borowska A, Puppel K, Kuczynska B, Cieslak J.β-lactoglobulin is one of the most abundant milk whey proteins in many mammal species, including the domestic horse. The aim of this study was to screen for polymorphism in the equine LGB1 and LGB2 gene sequences (all exons, introns, and 5'-flanking region) and to assess potential relationship of particular genotypes with gene expression levels (measured in milk somatic cells) and milk composition traits (protein, fat, lactose, and total β-lactoglobulin content). Direct DNA sequencing analysis was performed for twelve horse breeds: Polish Primitive Horse (PPH), Polish Coldblood Horse (PCH), ...
Production technology, nutritional, and microbiological investigation of traditionally fermented mare milk (Chigee) from Xilin Gol in China.
Food science & nutrition    December 9, 2019   Volume 8, Issue 1 257-264 doi: 10.1002/fsn3.1298
Guo L, Xu WL, Li CD, Ya M, Guo YS, Qian JP, Zhu JJ.Mare milk originated from female horses, known as mares, to feed their foals during lactation. The health-promoting characteristics of traditionally fermented mare milk (Chigee) are well known for the function of clinic treatment in the traditional Mongolian medicine. This study was conducted to investigate the production technology of Chigee and to evaluate the nutritional and microbiological characteristics of mare milk and Chigee based on 188 samples. The nutritional analysis of mare milk and Chigee indicated that lactose significantly decreased from 6.95 ± 0.45% to 2.82 ± 1.65% and a...
The Level of Prolactin, Serum Amyloid A, and Selected Biochemical Markers in Mares Before and After Parturition and Foal Heat.
Journal of equine veterinary science    November 14, 2019   Volume 84 102854 doi: 10.1016/j.jevs.2019.102854
Krakowski L, Brodzki P, Krakowska I, Opielak G, Marczuk J, Piech T.The aim of the study was to determine the level of prolactin (PRL), serum amyloid A (SAA), and selected biochemical markers (T-Chol, AST, TP, Mg, P, and Ca) in the blood of mares during the perinatal period. The study involved 14 mares of the Polish Coldblood Horse breed, which were in the third trimester of pregnancy. Blood was collected for testing 2 weeks before parturition and then 24 hours after delivery and in the foal heat (9 days) and 9 days after ovulation and breeding. The research revealed significant differences in the level of PRL and SAA before and after delivery. The highest...
Phosphorus excretion by mares post-lactation.
Journal of animal physiology and animal nutrition    November 13, 2019   Volume 104, Issue 6 1912-1918 doi: 10.1111/jpn.13251
Fowler AL, Pyles MB, Hayes SH, Crum AD, Lawrence LM.Across the equine literature, estimates of true P digestibility range from -23% to 79%. This large range cannot be explained by differences in P intake or phytate-P intake alone. However, differences in endogenous P secretion into the GI tract may explain the variation. In horses, excess absorbed P is not excreted in the urine but is re-secreted into the GI tract, increasing faecal P and leading to estimates of low P digestibility. Thus, accurate estimates of P digestibility can only be obtained if absorbed P is retained in the horse. The objective of this study was to examine P digestibility ...
Fetal Death Associated With Premature Mammary Gland Development and Lactation in a Mare Treated With Weekly Injections of Long-Acting Progesterone.
Journal of equine veterinary science    July 18, 2019   Volume 81 102783 doi: 10.1016/j.jevs.2019.07.004
McAfoos JL, Ellerbrock RE, Canisso IF.A 14-year-old, 530-kg, multiparous, pregnant Quarter Horse mare was referred for evaluation of premature mammary gland development and lactation. The mare was in the seventh month of gestation. The mare had a history of subfertility and was receiving weekly injections of long-acting progesterone, prescribed by the referring veterinarian. The last dose had been administered four days before presentation. Upon presentation, the mare had vital signs within normal limits, a moderately developed, nonpainful udder with galactorrhea, and no vulvar discharge. Transrectal palpation revealed a well-tone...
Selenium and Vitamin E Concentrations in a Healthy Donkey Population in Central Italy.
Journal of equine veterinary science    April 25, 2019   Volume 78 112-116 doi: 10.1016/j.jevs.2019.04.003
Bazzano M, McLean A, Tesei B, Gallina E, Laus F.Selenium and vitamin E protect the body against oxidative stress. Clinical manifestations of their deficiency in equids include neurologic and muscular symptoms. Despite the importance of donkeys as working and production animals, there is a dearth of scientific data on selenium and vitamin E normal values. Therefore, the aim of this study was to investigate the plasma concentrations of selenium and vitamin E in healthy donkeys belonging to different ages, sexes, and productive phases. Animals were divided into five groups including foals (group A: n = 7, n = 4 males and n = 3 females), wea...
Inappropriate lactation in a 15-year-old thoroughbred mare.
The Canadian veterinary journal = La revue veterinaire canadienne    April 18, 2019   Volume 60, Issue 4 430-433 
To T.A 15-year-old thoroughbred non-pregnant mare was presented with ongoing inappropriate lactation. The most likely cause, equine Cushing's disease, was ruled out through biochemical testing. Milk cytology and bacterial culture showed no evidence of mastitis or neoplasia. Idiopathic inappropriate lactation was diagnosed and treatment with pergolide was recommended. Lactation inappropriée chez une jument Pur-sang âgée de 15 ans. Une jument Pur-sang non gravide âgée de 15 ans a été présentée avec une lactation continue inappropriée. La cause la plus probable, la maladie de Cushing, a ét...
Animal and environmental factors associated with gestation length in the endangered Old Kladruber horse.
Theriogenology    February 20, 2019   Volume 129 116-120 doi: 10.1016/j.theriogenology.2019.02.013
Malinska M, Havlicek Z, Koru E, Rezac P.Little is known about factors influencing gestation length in heavier types of horses. The objective was to assess the effects of the weight and age of mares, weight and sex of foals, lactation, month and year of conception, month of foaling, stallion and mare on gestation length in the endangered Old Kladruber breed that once served as a heavy coach horse for ceremonies of the Imperial Court in Vienna. The study was performed at the stud farm Slatinany, Czech Republic and reports data from foaling seasons between 2001 and 2018. A total of 649 gestations were included in the study. Gestation i...
Effect of dietary supplementation with long-chain n-3 fatty acids during late gestation and early lactation on mare and foal plasma fatty acid composition, milk fatty acid composition, and mare reproductive variables.
Animal reproduction science    February 13, 2019   Volume 203 33-44 doi: 10.1016/j.anireprosci.2019.02.005
Kouba JM, Burns TA, Webel SK.The effects of dietary marine-derived n-3 fatty acids (FA) on mare milk and mare and foal plasma FA, postpartum ovarian follicular growth and prostaglandin concentrations were evaluated. Sixty days prior to expected foaling dates, mares were assigned to one of three diets: corn oil (CORN, n = 6), docosahexaenoic acid (DHA) diet (D; 12.64 g/d, n = 7), or eicosapentaenoic acid (EPA) and DHA (ED; 8.84 g EPA, 10.43 g DHA/d, n = 7). Milk and plasma were collected for FA analysis. Follicular data were recorded through the first postpartum ovulation. Post-ovulation serial blood samp...
A preliminary study on the use of jenny colostrum to improve quality in extenders for freezing donkey semen.
Cryobiology    January 24, 2019   Volume 87 110-114 doi: 10.1016/j.cryobiol.2019.01.009
Álvarez C, Luño V, González N, Gil L.Sperm quality in donkeys (Equus asinus) after freezing thawing is still considered lower than that from other animals, including horses. The aim of this study was to test a new freezing extender supplemented with jenny colostrum on donkey sperm. After thawing, we evaluated sperm motility by means of computer-assisted analysis, viability by SYBR-14 and propidium iodide (PI), membrane functional integrity by HOS-test and acrosome integrity by isothiocyanate conjugated with peanut agglutinin (FITC-PNA) and PI. Ejaculates were collected from five fertile Donkeys. Sperm samples were pooled, diluted...
5′-flanking variants of equine casein genes (CSN1S1, CSN1S2, CSN2, CSN3) and their relationship with gene expression and milk composition.
Journal of applied genetics    October 16, 2018   Volume 60, Issue 1 71-78 doi: 10.1007/s13353-018-0473-2
Cieslak J, Wodas L, Borowska A, Pawlak P, Czyzak-Runowska G, Wojtowski J, Puppel K, Kuczynska B, Mackowski M.Genes encoding casein proteins are important candidates for milk composition traits in mammals. In the case of the domestic horse, our knowledge of casein genes is limited mainly to coding sequence variants. This study involved screening for polymorphism in 5'-flanking regions of four genes encoding equine caseins (CSN1S1, CSN1S2, CSN2, and CSN3) and making a preliminary assessment of their effect on the gene expression (on the mRNA and protein levels) and milk composition traits in selected horse breeds. Altogether, 23 polymorphisms (21 described previously SNPs and two novel InDels) were fou...
Freezing point and other technological properties of milk of the Polish Coldblood horse breed.
Journal of dairy science    September 7, 2018   Volume 101, Issue 11 9637-9646 doi: 10.3168/jds.2018-15012
Cais-Sokolińska D, Danków R, Bierzuńska P, Kaczyński ŁK, Chudy S, Teichert J, Dobek A, Skotarczak E, Pikul J.Mare milk is a valued and sought-after raw material for the production of innovative dairy products. The high demand, low supply, high price, and lack of accurate characterization of the milk of a given horse breed may provoke its deliberate fraudulent dilution. The aim of this work was to analyze the freezing point against a background of various selected technological parameters of Polish Coldblood mare milk. Research was carried out on multiparous Polish Coldblood mares from 5 to 8 yr of age with live weights between 618 and 851 kg. Their milk was tested on d 1, 3, and 7 postpartum and once...
The contribution of total and free iodothyronines to welfare maintenance and management stress coping in Ruminants and Equines: Physiological ranges and reference values.
Research in veterinary science    February 2, 2018   Volume 118 134-143 doi: 10.1016/j.rvsc.2018.01.025
Ferlazzo A, Cravana C, Fazio E, Medica P.In order to acquire a pattern of thyroid involvement in welfare maintenance in Ruminants and Equines, this review summarizes data concerning the reference values of total and free iodothyronines and their modifications in physiological conditions and in different management conditions (pregnancy, lactation, weaning, growth, isolation, restraint, shearing, confinement and transportation). Thyroidal and extrathyroidal tissues efficiently respond to management practices, giving a differentiated contribution to circulating iodothyronine changes. The hormonal response could be mainly attributed to ...
Serum bone biomarkers osteocalcin and pyridinoline in mares during pregnancy and lactation, and in foals during early post-natal life.
Research in veterinary science    January 31, 2018   Volume 118 34-40 doi: 10.1016/j.rvsc.2018.01.007
Anderson ST, Kidd LJ, Barton AJ, Greer RM.Breeding mares typically foal yearly. Little is known about the dynamics of maternal bone stores during gestation and lactation, the timing of any maternal bone mobilisation, re-accretion post-foaling, or the dynamics of bone metabolism in foals. We measured serum osteocalcin (OC) and serum pyridinoline (PYD) concentrations in 18 mares monthly from 6months gestation to foaling, and in both mares and foals for 4months after birth. From 6 to 11months of gestation, there was no change in mean monthly OC. Serum PYD increased between 7months gestation and foaling. After foaling, mean serum OC was l...
Influence of sulpiride treatment on the level of prolactin and immunoglobulins in the peripheral blood of mares during the postpartum period.
Acta veterinaria Hungarica    September 29, 2017   Volume 65, Issue 3 417-428 doi: 10.1556/004.2017.039
Migdał A, Migdał Ł, Zagrajczuk A, Kochan J, Nowak A, Okólski A.The aim of this study was to determine the effect of increased levels of prolactin (PRL) on the concentration of immunoglobulins in the blood, colostrum and milk of mares. The study was conducted on 12 mares of the Polish Pony breed (6 in the control and 6 in the experimental group). To induce hyperprolactinaemia in mares of the experimental group, 750 mg sulpiride was administered orally once a day. The initial PRL concentration was 52.22 ± 11.21 ng/ml in the control group and 49.39 ± 10.12 ng/ml in the experimental group. In the subsequent days, the concentration of PRL dynamically changed...