Effect of heat stress during the dry period on milk yield and reproductive performance of Holstein cows

This study aimed to determine the influence of heat stress during the dry period on milk yield and reproductive performance of Holstein cows in a hot environment. Breeding and milk production records of cows, as well as meteorological data between 2017 and 2020 from a commercial dairy herd (n = 12,102 lactations), were used to determine the relationship between climatic conditions during the dry period (average of the temperature-humidity index (THI) at the beginning, middle, and end of the dry period) and reproductive efficiency and milk yield traits. THI was divided into < 70 (no heat stress), 70-80 (moderate heat stress), and > 80 (severe heat stress). First-service pregnancy rate of cows decreased (P < 0.01) with increasing hyperthermia during the dry period (9.5, 7.3, and 3.4% for THI < 70, 70-80, and > 80, respectively). All-service pregnancy rate was highest (P < 0.01) for cows not undergoing heat stress during the dry period (60.2%) and lowest (42.6%) for cows with severe heat stress during the dry period. Cows not experiencing heat stress during the dry period required a mean ± SD of 5.6 ± 3.8 services per pregnancy compared with 6.5 ± 3.6 (P < 0.01) for cows subjected to THI > 80 during the dry period. Cows not suffering heat stress during the dry period produced more (P < 0.01) 305-day milk (10,926 ± 1206 kg) than cows subjected to moderate (10,799 ± 1254 kg) or severe (10,691 ± 1297 kg) heat stress during the dry period. Total milk yield did not differ (P > 0.10) between cows not undergoing heat stress (13,337 ± 3346 kg) and cows subjected to severe heat stress during the dry period (13,911 ± 4018 kg). It was concluded that environmental management of dry cows during hot months is warranted to maximize reproductive performance and milk yield in the following lactation.

Cooling Holstein cows for 60 days prepartum in summer: effects on prepartum physiology, postpartum productivity, and calf growth

Heat stress (HS) during the dry period of dairy cows in hot and dry conditions compromises the physiological status and mammary gland development of dairy cows, thereby negatively affecting milk component yield in the subsequent lactation. Our objective was to evaluate the effects of cooling Holstein cows under moderate or higher HS conditions (i.e., ambient temperature higher than 30 °C, with a temperature-humidity index of 78.2 units) during the dry period on prepartum physiological status, postpartum productivity, and calf growth. Twenty-four multiparous Holstein cows were divided into two groups: one with a cooling system based on spray and fans under a pen shade (CL, n = 12) and the other not-cooled (NC, n = 12). The cooling system operated 10 h/d (09:00-19:00 h) for 60 d prepartum. During the morning, rectal temperature and respiration frequency were lower in CL cows, but not in the afternoon, which was attributed to higher (P < 0.01) dry matter intake by CL cows. Total serum protein was higher (P < 0.01) in CL cows, but hemoglobin was higher in NC cows (P < 0.01), with no differences in other electrolytes, hormones, hematological components, and metabolites. Milk fat and fat and fat-protein corrected milk were higher (P < 0.05) in CL cows. Female and birth weight trended (P = 0.08) to be higher in CL cows. Cooling cows during the dry period had a limited effect on physiology prepartum but increased postpartum productivity of Holstein cows under hot and dry conditions.

Characterization of the Worthen Sparrow (Spizella wortheni)'s Nest Building Materials in Northeastern Mexico

The study was conducted within a well-managed beef cattle operation in northeastern Mexico. Each nest was weighed and dissected to obtain the plant and animal material used to build the nests. The number of materials present per nest and relative frequency were determined. Twenty-one building materials were used. Over the years, Muhlenbergia torreyi represented 85.5% of the total biomass of the nests, and Aristida longiseta, Bouteloua gracilis, Brickellia canescens, Purshia mexicana and Cirsium ehrenbergii constituted 2.45, 2.80, 2.44, 1.34 and 1.11% of the total biomass, respectively. The above-mentioned grasses represented 95.62% of the total biomass. Material of animal origin was horse and cow hair, which represented 0.84 and 0.58% of the total biomass, respectively. It was concluded that, at the study site, Muhlenbergia torreyi was a key nest-building material for the Worthen sparrow nest.

Effects of parity, seasonal heat stress, and colostrum collection time postpartum on colostrum quality of Holstein cattle in an arid region

The aim of this study was to determine effects of parity (primiparous vs. multiparous), seasonal heat stress at calving (summer vs. winter), and time postpartum on some parameters associated with colostrum quality in Holstein cows reared in the Sonoran Desert ecosystem. Forty-seven cows (11 primiparous and 36 multiparous) expected to calve during summer, and 46 cows during winter (14 primiparous and 32 multiparous) were randomly selected. Management and feeding before and after parturition were similar for cows in both seasons. After parturition, colostrum from all cows was evaluated for volume, weight, temperature, density, and content of fat, protein, solids non-fat (SNF), and immunoglobulins (IGG). Data were analyzed with a model that included effects of parity status, calving season, and time postpartum, as well as all interactions. Colostrum produced in summer was warmer (P < 0.01) by almost 6 °C than winter colostrum, while colostrum from multiparous was warmer (P = 0.02) by 1.2 °C than that produced by primiparous cows. Colostrum volume and weight were not impacted by parity, calving season or time postpartum. Density, protein, and SNF content in colostrum were higher (P < 0.01) in multiparous vs. primiparous cows, as well as at parturition (0 h postpartum) than at 12 h postpartum (P < 0.01). At calving (0 h), spring colostrum had higher fat content (P < 0.01) and lower (P < 0.01) IGG concentration than that collected in summer, and no difference (P > 0.05) between seasons was observed for these components at 12 h postpartum. Multiparous cows produced colostrum with higher (P < 0.01) IGG concentrations than primiparous cows. In conclusion, only 0-h colostrum and that from multiparous cows was categorized as "Excellent," meanwhile the colostrum produced under summer heat stress was characterized as "Good" with reduced fat content. While the lacteal secretion collected at 12 post-partum still classified as colostrum, substantially lower contents of IGG, protein, fat, and SNF decreased its classification to "Poor" from the classification of "Excellent" at 0 h postpartum.

Climatic and calf-related risk factors associated with failure of transfer of passive immunity in Holstein calves in a hot environment

This retrospective observational study aimed to assess the effect of temperature-humidity index (THI) at calving and in the last trimester of pregnancy and calve-related factors affecting passive transfer of maternal immunoglobulin using Brix refractometry in Holstein calves. Blood samples from 4411 Holstein calves from a single large dairy farm in spring 2022 were used. A subset of data containing 6318 calvings was used to determine the effect of climatic conditions on the occurrence of agammaglobulinemia. Risk factors predictive of failure of passive transfer (FPT) were calculated using multiple logistic models. Females were 1.4 times more likely not to have FPT (56%; Brix% > 8 equivalent to ≥ 10 g/L IgG) than males (47.2%). Calves born as singles increased the likelihood of not presenting FPT (52.6%) than calves born as twins (42.9%). Calves from cows with no dystocic delivery had a lower risk for FPT (odds ratio = 2.3) than calves from cows with dystocia. Agammaglobulinemia was 1.5 and 1.8 times more likely to occur in calves with THI ≥ 80 and ≥ 82 in the last trimester of gestation and at calving, respectively, than in calves not experiencing heat stress. Agammaglobulinemia was twice as likely to occur in male than in female calves. Calves with birth weight ≥ 37 kg and gestation length ≥ 275 kg were less likely to present agammaglobulinemia than lighter calves and calves with shorter gestation periods. This study raises questions for management practices in Holstein calves undergoing in utero heat stress and around calving to avoid agammaglobulinemia.

Ovarian activity and reproductive responses of lactating Angus cows due to a mineral supplementation throughout a timed AI protocol

Two experiments were conducted to evaluate the effect of intramuscular administration of minerals during a TAI program on the reproductive responses of lactating Angus cows. All cows (n=353) were subjected to a 9-day TAI program based on CIDR insertion plus injections of estradiol, cloprostenol, and eCG, and then TAI 48 h later. In experiment 1, two groups were randomly created, one control with a placebo injection (CON, n=109), and the second received 10 mL of Fosfosan® (MIN, n=172) on day 0 of the synchronization. Conception rate (66.9 vs. 55%) and estrus percentage (55.8 vs. 44%) were higher (P≤0.05) in MIN than in CON cows. Given these results, a second experiment was conducted randomly assigning the cows to two treatments (n=36 each): a single injection of 10 mL of Fosfosan® (MIN-O) on day 0 or two injections of 10 mL of Fosfosan® (MIN-T) on synchronization days 0 and 7. Four cows of each treatment were randomly selected to be scanned with transrectal ultrasound before and during the synchronization protocol to assess ovarian structures and cyclicity, and at day 39 post-TAI for pregnancy diagnosis. Also, blood samples were obtained for the determination of serum minerals and progesterone (P4) concentrations. The number of mineral injections did not affect conception rate (P≥0.1229) conception rate, serum mineral and P4 concentrations, number, and size of emerging follicles, or follicle size according to 1 to 4 classifications. The MIN-T promoted (P<0.05) earlier follicular wave emergence than MIN-O. However, MIN-O cows had a dominant follicle of 15.12 mm, which is more significant (P<0.05) than that in MIN-T cows (13.5 mm). In conclusion, providing a single mineral injection of Fosfosan® at the start of a TAI program is an excellent reproductive strategy in lactating Angus cows to improve the dominant follicle growth, estrus response, and conception rate.

The Effect of Month of Harvesting and Temperature-Humidity Index on the Number and Quality of Oocytes and In Vitro Embryo Production in Holstein Cows and Heifers

The aim of this study was to evaluate the effect of the month of oocyte harvesting and the temperature-humidity index on oocyte number and quality harvested from Holstein cows and heifers, oocyte developmental competence, and total embryos produced in an area of intense ambient temperature for most of the year. A total of 5064 multiparous lactating cows and 2988 nulliparous heifers were used as oocyte donors and distributed across the months of the year. Overall, total oocytes per collection did not differ (p > 0.05) between cows (16.6 ± 2.7) and heifers (15.1 ± 1.8), but oocyte developmental competence was lower (p < 0.05) in cows (21.3 ± 5.4) than heifers (25.5 ± 4.0). For cows, the total number of oocytes harvested was two-fold higher (p < 0.05) in November than in May. For heifers, the total number of oocytes harvested was highest in April (17.19 ± 0.53) and lowest in May (10.94 ± 0.32; p < 0.05). For cows, total embryos were highest in November (2.58 ± 0.42) and lowest in August (1.28 ± 0.10; p < 0.05). Thus, taken together, these results indicate that severe heat stress impaired the number and quality of oocytes harvested from donor Holstein multiparous cows and heifers, oocyte developmental competence, and total embryos produced in this area of intense ambient temperature for most of the year.

A Circular Economy Approach to Integrate Divergent Ruminant Production Systems: Using Dairy Cow Feed Leftovers to Enhance the Out-of-Season Reproductive Performance in Goats

Based on a circular economy approach, we evaluated the possible effect of targeted supplementation with leftover feed from dairy cows (i.e., intensive system) on the reproductive performance of crossbred/rangeland goats (i.e., extensive system) in arid Northern Mexico. During the deep-anestrous season (i.e., March-April, 25° North), multiparous goats (n = 38) with a similar body weight (BW) and body condition score (BCS) were randomly assigned to two groups: (1) supplemented group (SG; n = 19; BCS: 1.76 ± 0.07; BW: 43.7 ± 1.8 kg), receiving 400 g goat d-1 of dairy-cow-feed leftovers prior to grazing; and (2) non-supplemented group (NS; n = 19; BCS: 1.76 ± 0.06; BW: 44.3 ± 2.5 kg). Both groups were directed to the rangeland for a period of ≈8 h. While the experimental period lasted 36 d, the experimental breeding considered 11 d (d0-d10). The anovulatory status of goats was ultrasonographically confirmed on days -20, -10, and -1 prior to male-female interaction. Previously, bucks were separated for 3 weeks from the experimental females and received exogenous testosterone every third day (i.e., 50 mg i.m.) prior to mating. With respect to the response variables, namely BW, BCS, blood glucose levels (BGLs), estrus induction (GIE, %), latency to estrus (LTE, h), estrus duration (ED, h), and luteal tissue volume (LTV, mm), no differences (p > 0.05) occurred between experimental groups. However, the response variables, namely goats ovulating (GO, %; 78.9 vs. 47.3), total number of corpuses luteum (TNCL, n; 27 vs. 13), ovulation rate (OR, n; 1.42 vs. 0.73), multiple ovulation (MO, %; 73.3 vs. 55.5), and pregnancy rate on d 36 (PRd36, %, 68.4 vs. 36.8), favored (p < 0.05) the SG over the NS goats. Our results demonstrate that connecting the circularity of two divergent ruminant production systems (i.e., cow-intensive and goat-extensive) by using dairy cows' feed leftovers as a targeted supplementation strategy in anestrous goats under a marginal-rangeland production system enhanced out-of-season reproductive outcomes (i.e., ovulation rate and pregnancy rate), thus benefiting marginal goat producers and their families.

Holstein heifers in desert climate: effect of coat color on physiological variables and prediction of rectal temperature

Two hundred Holstein heifers were divided by hair coat color in black (n₁ = 60), white (n₂ = 62), and mixed (n₃ = 78) to accomplish two objectives: (1) to compare physiological variables using an analysis of variance, and (2) to construct regression equations to predict rectal temperature. In each heifer, rectal temperature (RT), respiration frequency (RF), and body surface temperatures (obtained with infrared thermography in eye, nose, forehead, head, neck, ear, shoulder, flank, belly, leg, loin, rump, and vulva) were measured. Black heifers had more RF and RT (P < 0.01) than mixed and white coat heifers; white heifers had similar RT than mixed color heifers, but they exhibited less RF (P < 0.05). In general, black and mixed coat color heifers had higher BST (P < 0.01) than white heifers in the majority of the anatomical regions measured. For black coat heifers, the best regression model to predict RT included three predictor variables: [RT = 35.59 - 0.013 (RH) + 0.045 (RF) + 0.019 (T_Ear); R² = 71%]. For white coat heifers, the best model included two predictor variables: [RT = 35.29 + 0.035 (RF) + 0.033 (T_Forehead); R² = 71%]; and for mixed coat color heifers, the best model included two predictor variables: [RT = 35.07 + 0.022 (RF) + 0.038 (T_Head); R² = 44%]. Heifers with dark hair coat color showed higher physiological constants than white heifers; the prediction of rectal temperature was more precise in heifers with well-defined hair coat color. Physiological and climatic variables, along with infrared thermography, represent an appropriate combination to predict rectal temperature in Holstein heifers with predominant white or black hair coat color.

Sero-epidemiology of brucellosis in small ruminants on rangeland in northern Mexico

The seroprevalence of Brucella antibodies in serum of goats and sheep reared on semi-arid pastoral systems of northeastern Mexico was assessed. Additionally, species, gender, and predominant breed were evaluated as risk factors for seropositivity to brucellosis. Data were from 375 flocks of goats or co-mingled goats and sheep. Serum samples from 11001 goats and 4741 sheep collected between 2016 and 2019 were analyzed with the brucellosis card test. The disease affected 12% of flocks. The overall prevalence of brucellosis seropositivity in goats and sheep were estimated at 2.1% (95% CI = 1.78-2.31) and 0.8% (95% CI = 0.58-1.10), respectively. Brucellosis seropositivity was two times more likely (p < 0.01) in goats than sheep. The risk of seropositivity to brucellosis for goats and sheep was 2.3 and 3.2 times higher (p < 0.01) in females than males. Toggenburg goats were more likely (p < 0.01) to be seropositive to brucellosis than all other breeds of goats, whereas criollo sheep were more likely to be seropositive to brucellosis compared to hair sheep composite breeds. The current study revealed that, despite the absence of Brucella vaccination, brucellosis is not widely distributed in the study area. Also of all animals screened, seropositivity to Brucella infection was highest in Toggenburg when compared to other dairy and meat breeds; Criollo sheep also presented the highest seropositivity to brucellosis compared to hair sheep composite breeds. Finally, females compared to males had increased odds of testing positive for brucellosis.

Ferulic acid supplementation for 40 days in hair ewe lambs experiencing seasonal heat stress: short-term effects on physiological responses, growth, metabolism, and hematological profile

Free ferulic acid (FA) is a natural compound with antioxidant properties which mitigates the negative effects of cold stress in sheep; however, its impact on thermoregulatory responses in heat-stressed sheep has not been defined. The objective was to evaluate the effects of FA supplementation on physiological responses, serum analyte concentrations, and the hematological profile of heat-stressed hair ewe lambs. Twenty-two Dorper × Katahdin ewe lambs (initial body weight = 23.5 ± 2.8 kg and age = 4 months) were housed in individual pens for 40 days and assigned under a randomized complete block design to the following treatments (n = 11): basal diet with 0 (control) or 250 mg of FA/kg of feed. The FA × sampling day interaction only affected serum concentration of some metabolic hormones; particularly on day 20 of the trial, FA increased (P < 0.01) insulins and the insulin to glucose ratio while decreased (P = 0.05) thyroxine. Overall, supplemental FA did not affect rectal temperature, respiratory rate, most body surface temperatures, feedlot performance, and serum concentrations of metabolites, electrolytes, triiodothyronine, and cortisol. In addition, FA only tended to decrease (P ≥ 0.09) erythrocyte count and plaquetocrit and to increase (P = 0.08) mean corpuscular volume. In conclusion, FA supplementation did not improve the growth nor thermoregulatory capacity of heat-stressed hair ewe lambs. Still, it partially modulated the metabolism to reinforce some energetic adaptive mechanisms when the ambient temperature was ≥ 35 °C.

Fertility of Holstein cows and heifers submitted to timed artificial insemination and receiving one or two doses (12 h apart) of semen

The objective of this retrospective study was to assess the effect of receiving a single (n = 50,285) or double (n = 4392) artificial insemination (AI), 12 h apart, within a timed artificial insemination protocol on pregnancy per AI (P/AI) in nulliparous heifers (inseminated with either sex-sorted or conventional semen) and pluriparous Holstein cows in a commercial dairy herd. Also, this study aimed to investigate the relationship between temperature-humidity index (THI) and time of the first AI and fertility. Fertility of cows receiving two AI with normothermia (THI <68) was higher (p < .05) than cows receiving a single AI (42.9% vs. 36.4%). P/AI of cows receiving two AI with severe heat stress (THI >85) was higher (p < .05) than cows receiving a single AI (21.0% vs. 12.6%). Regardless of heat stress conditions, applying the first AI in the morning increased (p < .05) P/AI in cows with double AI than in cows whose first AI occurred in the afternoon (38.4 vs. 33.3%). With moderate heat stress, and sexed-sorted semen, P/AI to timed AI was higher (65.0 vs. 51.9%; p < .05) in heifers receiving double AI than those serviced once. It was concluded that double AI, 12 h apart, enhanced fertility at timed AI than herd mates with a single AI, particularly with heat stress at breeding.

Prediction of rectal temperature in Holstein heifers using infrared thermography, respiration frequency, and climatic variables

The objective of this study was to develop an equation to predict rectal temperature (RT) using body surface temperatures (BSTs), physiological and climatic variables in pubertal Holstein heifers in an arid region. Two hundred Holstein heifers were used from July to September during two consecutive summers (2019 and 2020). Respiratory frequency (RF) was used as a physiological variable and ambient temperature, relative humidity and temperature-humidity index as climatic variables. For the body surface temperatures, infrared thermography was used considering the following anatomical regions: shoulder, belly, rump, leg, neck, head, forehead, nose, loin, leg, vulva, eye, flank, and lateral area (right side). Initially, a Pearson correlation analysis examined the relationship among variables, and then multiple linear regression analysis was used to develop the prediction equation. Physiological parameters RT and RF were highly correlated with each other (r = 0.73; P˂0.0001), while all BST presented from low to moderate correlations with RT and RF. BST forehead temperature (FH) showed the highest (r = 0.58) correlation with RT. The equation RT = 35.55 + 0.033 (RF) + 0.030 (FH) + e_i is considered the best regression equation model to predict RT in Holstein heifers in arid zones. This decision was made on the indicators R² = 60%, RMSE = 0.25, and AIC = 0.25, which were considered adequate variability indicators.

Effect of Replacing Sorghum Stubble with Tillandsia recurvata (L.) on Liveweight Change, Blood Metabolites, and Hematic Biometry of Goats

Tillandsia recurvata is an epiphyte that grows on the canopy of many trees in tropical and subtropical areas of America. The objective of this study was to evaluate the effect of partial or complete substitution of sorghum stubble with T. recurvata on liveweight change, metabolic profile, and complete blood count of goats fed increasing levels (0, 30, and 60%, dry matter basis) of T. recurvata. Thirty non-pregnant three-year-old, non-lactating, healthy mixed-breed goats, ten animals per treatment (T0, T30, and T60), were adapted to diets and facilities for 14 days (d-14). Blood samples were collected at d-15, 28, and 56. At the last phase of the trial (from days 67 on), control goats tended to gain more (p = 0.09) weight than their counterparts consuming T. recurvata. Plasma protein, glucose, triglycerides, calcium, and phosphorus concentrations did not differ among dietary treatments (p > 0.05). Dietary treatment influenced red blood cells (higher for T60; p < 0.01), white blood cells (higher for T30; p < 0.05), mean corpuscular volume (higher for T0; p < 0.001), and mean corpuscular hemoglobin concentration (higher for T0; p < 0.01), although not the rest of the blood variables (p > 0.05). The hematocrit percentage tended to be higher (p = 0.06) in T30 than T0 and T60. It was concluded that replacing sorghum stubble with T. recurvata did not modify the metabolic status and maintained live weight of goats. Nevertheless, the use of T. recurvata as feed for goats would improve the nutrition of these animals in the dry season compared to the current diet obtained from an arid rangeland, reducing production costs, and would alleviate the damage caused by this aggressive epiphyte to host trees.

Termorregulación y respuestas reproductivas de carneros bajo estrés por calor. Revisión

Las temperaturas elevadas registradas durante la época de verano en las regiones cálidas comprometen la capacidad reproductiva de los animales domésticos. En carneros, el estrés por calor (EC) causa en el organismo una serie de ajustes fisiológicos, metabólicos, endocrinos y moleculares con el objeto de mantener normotermia y sobrevivir; sin embargo, varios de estos cambios se asocian negativamente con su fertilidad, principalmente los endocrinos. El EC en carneros provoca una disminución en las concentraciones sanguíneas de testosterona a través de diferentes mecanismos, y esto se refleja negativamente en el proceso de espermatogénesis y en la conducta sexual. En consecuencia, los carneros estresados por calor presentan baja calidad seminal y apetito sexual; a nivel de espermatozoides se ha observado daño estructural y en el ADN. Dada esta situación, se recomienda el uso de estrategias de mitigación del EC durante el verano en las explotaciones ovinas de regiones cálidas, tales como el uso de sombras en corrales, la administración de antioxidantes o modificaciones en la alimentación. Por lo tanto, el objetivo de este documento es revisar el conocimiento actual en relación al efecto del EC sobre la capacidad de termorregulación y reproductiva de los carneros, así como la aplicación de estrategias para su mitigación.

n-6 Polyunsaturated fatty acids in the feeding of late gestation hair ewes: the effects on thermoregulation, growth, and metabolism of heat-stressed growing lambs

The objective was to determine the effects of feeding soybean oil (SBO), an ingredient rich in n-6 polyunsaturated fatty acids (PUFA), to late gestation hair ewes on physiological responses, feedlot performance, and serum metabolite and electrolyte concentrations of their growing ewe lambs under outdoor heat stress conditions. Twenty-four Dorper × Pelibuey ewe lambs weaned (body weight = 21.5 ± 0.2 kg, age= 2 months, and multiple birth) born from ewes fed 0, 30, or 60 mg of SBO/kg dry matter (DM) during late gestation were selected (n = 8/treatment) to conduct a 30-day feeding trial during the summer season of a desert region (temperature = 34 °C and temperature-humidity index = 35 units). While rectal temperature was unaffected in any daytime, respiratory rate in the afternoon quadratically increased (P = 0.05) as the SBO levels increased from 0 to 60 mg/kg DM in the maternal diet. Final weight, average daily gain, and feed efficiency linearly increased (P = 0.04) with increasing levels of SBO. Body surface temperatures and serum concentration of glucose, cholesterol, triglyceride, total protein, urea, sodium, potassium, and chlorine did not vary by the SBO inclusion in the maternal diet. In conclusion, feeding late gestation hair ewes with source rich in n-6 PUFA appears to be an effective maternal nutritional strategy to improve post-weaning growth without compromising the thermoregulatory ability of their growing offspring under a heat stress environment.

Effect of co-positivity for brucellosis and tuberculosis on milk yield and fertility of Holstein cows

This study aimed to determine whether cows detected as tuberculosis (bTB) reactors and seropositive to brucellosis (bBR), as well as co-positive to bBR and bTB (bBR-bTB) and with a complete lactation before slaughter, were associated with reduced milk production and fertility. A total of 8068 productive and reproductive records of high-yielding Holstein cows from a single large dairy herd with a high prevalence of bTB and bBR were collected from 2012 to 2015. Lactation derived either from calving (n = 6019) or hormonally induced lactation (n = 2049), and all cows received growth hormone throughout lactation. For cows not induced into lactation, pregnancy rate to first service for healthy cows (C; 26.6%) was higher (P < 0.01) than bBR (15.2%), bTB (15.8%), and bBR-bTB (1.3%) cows. For induced cows, pregnancy rate to first service did not differ significantly among C, bBR, and bTB (14.5-17.3%) cows, but the percentage success of first service was extremely low (1.3%; P < 0.01) in bBR-bTB cows. Services per pregnancy (only pregnant cows) were lowest for C (3.3 ± 2.9; P < 0.01) and highest (6.4 ± 3.4) for bBR-bTB non-induced cows. This variable was lowest for C (2.9 ± 2.5; P < 0.01) and highest for bBR-bTB non-induced cows (6.3 ± 3.1). Pregnancy rate to all services did not differed for C (79.5%), bBR (76.7%), and bTB (75.9%) but was lower (58.9%; P < 0.01) for bBR-bTB non-induced cows. For induced cows this variable was highest for bBR (53.3%) and lowest for bBR-bTB (34.1%; P < 0.01) non-induced cows. 305-d milk production was increased by 4%, and total milk yield by 7% in TB-positive cows compared to that of the negative cows non-induced hormonally into lactation. This study showed the negative impact of the co-positivity for bTB and bBR on the reproductive efficiency of Holstein cows, although positive bTB and bBR tests enhanced milk yield.

Growth performance and mammary gland development of Holstein calves fed milk with 15% solids and treated with growth promoters

The objective of this study was to evaluate growth performance, and mammary gland parenchyma (PAR) development in Holstein female calves fed whole milk combined with milk replacer for 15% total solids (15TS) or only milk (11% TS; 11TS). The effects of zilpaterol hydrochloride (ZH) and an estrogenic implant (EI) on growth performance, serum metabolites, and PAR development in post-weaning calves (63-90 days of age) fed 15TS or 11TS were also investigated. In the first phase, 78 calves were randomly divided into two groups (n = 39/group), 15TS, or 11TS (5 to 8 L/day; starter ad libitum). After weaning, calves were randomly assigned to four treatments, no EI, EI, ZH, and ZH-EI. In phase 1, 15TS calves had greater (P < 0.01) average body weight at weaning than 11TS calves (82.0 ± 5.8 vs. 74.1 ± 5.7 kg). Pre-weaning average daily gain (718 ± 67 vs. 576 ± 64 g/day) was higher (P < 0.01) for 15TS calves than 11TS calves. Feed/gain (1.5 ± 0.3 vs. 1.8 ± 0.3 kg of DMI/kg of gain) was lower (P < 0.01) for 15TS calves than 11TS calves. PAR area (8.8 ± 3.3 vs. 5.0 ± 1.6 cm²) was greater (P < 0.01) for 15TS calves than 11TS calves. No differences (P > 0.10) in average daily gain (986 ± 79 g/day across treatments) were observed in calves receiving ZH, EI, or ZH-EI fed 15TS or 11TS diets previously. However, the PAR area of 15TS calves administered ZH-EI was 2.2 times greater (P < 0.01) than 11TS calves with no ZH and CI. This study demonstrated the benefits of supplying milk with 15% TS for enhancing overall animal growth and PAR development. Further use of ZH and EI during the post-weaning period did improve mammary PAR growth.

Growth performance and changes in physiological, metabolic and hematological parameters due to outdoor heat stress in hair breed male lambs finished in feedlot

The aim of this study was to evaluate the effect of seasonal heat stress (HS) on productive performance, physiological responses, metabolism, and hematological profile of hair breed male lambs finished in feedlot. Twenty Dorper × Katahdin male lambs (body weight = 34.6 ± 1.4 kg and age = 4.5 months) were housed in individual pens and exposed to environmental conditions of summer HS (n = 10, temperature = 28.3 ± 4.0 °C and THI = 77.2 ± 5.4 units) or winter thermoneutrality (n = 10, temperature = 19.2 ± 2.6 °C and THI = 64.0 ± 3.0 units). Each season, a 30-day feeding test was conducted to measure study variables. Compared to thermoneutral lambs, heat-stressed lambs had lower (P < 0.01) growth rate and feed efficiency without changing dry matter intake. Heat-stressed lambs presented higher (P < 0.01) rectal temperature and respiratory rate through the daytime than termoneutral lambs. On most sampling days, summer HS caused lower (P < 0.01) serum concentrations of glucose, cholesterol, total protein, urea, potassium, and thyroid hormones, but higher (P < 0.01) serum triglyceride and chlorine values. Overall serum concentrations of cortisol and insulin were unaffected by summer HS. The blood of heat-stressed lambs showed lower (P ≤ 0.03) erythrocyte and platelet counts, hemoglobin, and hematocrit, but higher (P ≤ 0.03) erythrocyte size and leucocyte count than the blood of thermoneutral lambs. In conclusion, hair breed male lambs in response to chronic conditions of summer HS had slow growth but avoided hyperthermia due to the activation of physiological, metabolic and endocrine adjustments.

Impacts on two dairy breeds of adding a third (night) cooling event under extreme ambient heat

Impacts of an additional cooling event during the night on physiological and productive parameters of two breeds (B) of dairy cows under severe heat stress conditions were determined. Fifteen Holstein (H) and 15 Jersey x Holstein (JxH) cows were assigned to one of the two cooling strategies (CS), where the difference was an added 1 h cooling event during the night (i.e., 3X and 4X cooling events) with the 4X group having the added night cooling event. Maximum and minimum average temperature/humidity indices during the study were 86 and 77 units, respectively. There were no CS x B interactions for any response variable. Body condition score (BCS) was similar between CS, but H cows had higher (P<0.05) condition than JxH. There were no differences in rectal temperature due to CS or B. Respiration rate between breeds and cooling strategies were similar throughout the day. However body surface temperatures of head, thurl, right flank, and udder were higher (P<0.05) in 3X versus 4X cows, and H cows maintained a higher (P < 0.05) temperature in thurl and right flank than JxH during PM hours. Metabolites and hormone concentrations were not affected by CS, but H cows had lower (P < 0.05) triiodothyronine and higher (P < 0.05) thyroxine, than JxH. The 4X cows had higher (P<0.05) milk yield and milk energy output than 3X cows. While H cows produced more milk than JxH, the latter had higher (P < 0.05) milk component levels. In general, JxH cows were judged to have to demonstrate a more desirable physiological response and milk composition outcome than H cows. An additional night cooling event was judged to result in more desirable physiological and productive responses than in cows without this extra night cooling event under the extremely hot and dry environmental conditions during the study.

Risk for post-thrombotic syndrome after lower-limb deep vein thrombosis: location of the thrombus or residual thrombi?

BACKGROUND

Many works aimed to determine factors that influence the onset of postthrombotic syndrome after an acute episode of deep venous thrombosis. We aimed to compare the prognostic value of the most proximal extent of thrombus (proximal and distal DVT) versus the residual thrombosis as identified by venous ultrasonography performed during follow-up.

METHOD

We conducted a retrospective study of prospectively collected 1183 consecutive cohort patients in the RIETE registry after a first episode of deep venous thrombosis and assessed for postthrombotic syndrome after 12 months.

RESULTS

Multivariate analysis revealed that: residual thrombosis (OR 1.40; 95% CI 0,88-2,21), the presence of cancer (OR 1.38; 95% CI: 0,64-2,97), immobility (OR 1.31; 95% CI 0,70-2,43) and estrogen-containing drugs use (OR 2.08, 95% CI 0,63-6,83), all had a predictive value for the occurrence of PTS.

CONCLUSION

Our study results revealed that ultrasound finding of residual thrombosis is more predictive than proximal location of thrombus for postthrombotic syndrome after episode of deep venous thrombosis. Real life data from a large group of patients from the RIETE registry substantiates that.

Comparative clinical prognosis of massive and non-massive pulmonary embolism: A registry-based cohort study

AIMS

Little is known about the prognosis of patients with massive pulmonary embolism (PE) and its risk of recurrent venous thromboembolism (VTE) compared with non-massive PE, which may inform clinical decisions. Our aim was to compare the risk of recurrent VTE, bleeding, and mortality after massive and non-massive PE during anticoagulation and after its discontinuation.

METHODS AND RESULTS

We included all participants in the RIETE registry who suffered a symptomatic, objectively confirmed segmental or more central PE. Massive PE was defined by a systolic hypotension at clinical presentation (<90 mm Hg). We compared the risks of recurrent VTE, major bleeding, and mortality using time-to-event multivariable competing risk modeling. There were 3.5% of massive PE among 38 996 patients with PE. During the anticoagulation period, massive PE was associated with a greater risk of major bleeding (subhazard ratio [sHR] 1.72, 95% confidence interval [CI] 1.28-2.32), but not of recurrent VTE (sHR 1.15, 95% CI 0.75-1.74) than non-massive PE. An increased risk of mortality was only observed in the first month after PE. After discontinuation of anticoagulation, among 11 579 patients, massive PE and non-massive PE had similar risks of mortality, bleeding, and recurrent VTE (sHR 0.85, 95% CI 0.51-1.40), but with different case fatality of recurrent PE (11.1% versus 2.4%, P = .03) and possibly different risk of recurrent fatal PE (sHR 3.65, 95% CI 0.82-16.24).

CONCLUSION

In this large prospective registry, the baseline hemodynamic status of the incident PE did not influence the risk of recurrent VTE, during and after the anticoagulation periods, but was possibly associated with recurrent PE of greater severity.

Climate change vulnerability of confined livestock systems predicted using bioclimatic indexes in an arid region of México

Climate change is a major world-wide challenge to livestock production because food security is likely to be compromised by increased heat stress of the animals. The objective of this study was to characterize, using bioclimatic indexes, two livestock regions located in an arid zone of México, and to use this information to predict the impact of global warming on animal production systems of these regions located in the state of Baja California (México). A 5-year database (i.e., 2011 to 2015) consisting of about one million data points from two zones (i.e., coast, valley) from four meteorological stations in the north of Baja California were used. Bioclimatic indexes were constructed for the four types of livestock production systems most common in this region, being: dairy cattle, beef cattle, sheep, pigs. The temperature-humidity index (THI) thresholds used to classify heat stress were determined and scaled for each livestock species as: THI_beef and THI_pig 74 units; THI_milk 72 units; and THI_sheep 23 units. Statistical differences between indices were detected (P < 0.01) during summer for the valley and coast zones as (THI_beef = 72.9 and 51.8; THI_milk = 80.6 and 67.4; THI_pigs = 83.9 and 65.2; THI_sheep = 29.5 and 20.1 units). Coast zone weather did not suggest vulnerability of livestock production systems to heat stress at any time of the year, but heat stress risk during summer for valley zone dairy cattle, sheep and pigs was classified as severe, but lower for feedlot cattle. Prediction models showed significant adjustment just in the coastal zone for THImilk, THIsheep, and THIsheep, suggesting more impact of global warming during summer in the coastal zone. Use of management strategies to reduce heat load of domestic animals during summer in northern Baja California is essential to maintain their productivity, with more emphasis in the valley zone.

Efecto de la adición de clorhidrato de zilpaterol genérico en el perfil bioquímico y hematológico de ovinos de pelo engordados en corral

El objetivo fue evaluar la adición de clorhidrato de zilpaterol (CZ, genérico) en la dieta de ovinos de pelo de engorda, sobre variables hematológicas y bioquímicas como indicadores del estado de salud. Treinta y dos (32) corderos de pelo cruzados (Dorper x Pelibuey) se bloquearon por peso inicial y cuatro tratamientos y se asignaron aleatoriamente dentro de cada bloque: T1= dieta basal (grupo testigo), T2= dieta basal más 0.10 mg·kg-1 de PV d-1 de CZ (Grofactor®, Virbac México, Guadalajara, México), T3= dieta basal más 0.20 mg·kg-1 de PV d-1 de CZ y T4= dieta basal más 0.30 mg·kg-1 de PV d-1 de CZ. Se tomaron muestras de sangre los días 1, 15 y 30 del estudio. El perfil hematológico se estimó en muestras de sangre fresca, mientras que metabolitos, electrolitos y hormonas en muestras de suero. El diseño experimental fue bloques completos al azar y se efectuó análisis de polinomios ortogonales para determinar la tendencia de las respuestas a los niveles de CZ. Los niveles de colesterol y urea fueron mayores (P<0.05) en T3 que en T2; asimismo, el nivel de concentración corpuscular medio de hemoglobina fue mayor (P<0.05) en T1 que en T3, mientras que el ancho de distribución de eritrocitos fue mayor (P<0.05) en T2 y T3 que en T4. Los niveles de Na y el número de plaquetas mostraron tendencia lineal (P<0.05) a disminuir y aumentar, respectivamente, conforme los niveles de CZ aumentaron. Se observó tendencia cuadrática (P<0.05) en la concentración corpuscular media de hemoglobina y ancho de distribución de eritrocitos al aumentar la dosis de CZ (genérico). Las variables restantes no mostraron tendencias significativas a los niveles de CZ (genérico). Los valores de los perfiles bioquímico y hematológico se encontraron dentro del rango de referencia, lo que sugiere que la adición de CZ no alteró el estado de salud de corderos en engorda.

Free ferulic acid supplementation of heat-stressed hair ewe lambs: Oxidative status, feedlot performance, carcass traits and meat quality

Twenty-two Katahdin × Dorper ewe lambs (average weight = 23.5 ± 2.8 kg) were individually housed during a 40-d feeding study and then slaughtered to evaluate effects of free ferulic acid (FA; 0 and 250 mg/kg of feed) on oxidative status, feedlot growth, carcass and non-carcass traits, wholesale cut yields and meat quality under heat stress conditions. Overall feeding FA decreased protein oxidation without affecting oxidative stress index, while growth rate and feed efficiency increased only in the hottest period (i.e., 28 to 45 °C). The FA supplementation increased kidney-pelvic-heart and mesenteric fat deposition, as well as yields of forequarter, shoulder, ribs, loin, and breast and flank, but decreased yields of hindquarter, neck, plain loin and leg. Carcass characteristics and meat quality were unaffected by FA. Overall, FA supplementation of heat-stressed hair ewe lambs enhanced feedlot performance under extreme heat stress and increased internal fat reserves, while changing muscle mass deposition, possibly because it prevented protein oxidation.

Influence of blood metabolites and body condition score at parturition on fertility and milk yield in Holstein cows

Background: Variables associated with body tissue mobilization place dairy cows at greater risk of reproductive failure. Objective: To investigate the association between blood metabolites and body condition score (BCS) at the beginning of lactation and the reproductive efficiency and milk yield of Holstein cows in a hot environment. Methods: In total, 165 Holstein cows were selected for the study from which blood samples were taken to determine the concentration of various blood metabolites and their association with the reproductive efficiency and milk yield. Results: Cows with serum β-hydroxybutyrate (BHBA) ≤0.8 mmol/L one week postpartum were 3.3 times more likely to become pregnant at first service, and 2.2 times more likely to become pregnant before 80 d postpartum than cows with higher serum BHBA levels. The odds (OR 2.7; 95% CI 1.3–5.4; p<0.01) of a cow getting pregnant at first service were higher in cows with serum creatinine levels higher than 2.0 mg/dL one week postpartum than cows with lower blood levels of this metabolite. The BCS at 30 and 60 d postpartum that predicted pregnancy at first service and pregnancy to all services was 3.0. Blood urea nitrogen >15 mg/dL, creatinine <1.8 mg/dL, total protein ≤5.0 mg/dL one week postpartum, and >0.40 units of BCS loss during the first 30 d postpartum were critical threshold that predicted the likelihood of 305-d milk yield higher than 10,500 kg. Conclusions: Serum BHBA and creatinine one wk after calving as well as BCS 30 and 60 d post-calving provided reasonably accurate cut-off screening values to discriminate cows with better reproductive performance and higher 305-d milk yield.

Milk yield and composition and body weight of offsprings of mixed-breed goats on semi-arid rangelands with different rainfall

The objective was to characterize milk yield and composition from mixed-breed goats kidding in winter and grazing rangelands with 221 (n = 15), 334 (n = 20), or 441 (n = 12) mm of annual rainfall in northern Mexico (22-25°N). Weekly milk yield and composition were recorded and progeny growth performance assessed. Body weight loss during lactation was the highest (6.4 kg) for goats on rangeland with 441 mm of rainfall than goats on 221 mm (1.6 kg), or 334 mm (1.8 kg; P < 0.01). The highest daily milk yield was for goats on 221 mm (498 mL; P < 0.01). There was not an evident peak of lactation and milk yield increased uninterruptedly at the end of lactation. Milk fat was negatively related to milk yield and goats on rangeland with 334 mm had the greatest milk fat content (P < 0.001). Milk protein and lactose content were higher in goats on rangeland with 221 mm (P < 0.01). Goat kids on rangelands with 221 and 441 mm grew faster and were heavier (P < 0.001) at weaning than kids reared in other rangelands. Weaning weight was positively related to milk yield (P < 0.001); but not milk components (P > 0.05). In conclusion, moderate milk yield of mixed-breed goats on rangeland is feasible with parturitions in winter, and milk yield is not affected by reduced annual precipitation in rangelands of northern Mexico. Offspring growth performance depends on maternal milk yield, but not milk composition. Nevertheless, slow growth to weaning of offspring had adverse effects on time to reach adequate market weight.

The Effect of P4 + eCG Estrus Induction Protocol during the Deep and the Transition Anestrous Period on the Reproductive Performance of Crossbred Dairy Goats

Simple Summary

The effect of an ultra-short progesterone (P4) plus equine chorionic gonadotropin (eCG) based estrus induction protocol during deep seasonal anestrous, or the reproductive transition period upon reproductive performance in an arid environment (26° N) was assessed. Results confirm a multidimensional response of goats regarding the effectiveness of P4 + eCG estrus induction protocols, mainly modulated by a specific time within the anestrous season (June) or even by specific management or a particular environment at herd level (herd 1 in this study), although, it is quite remarkably non–dependent on the animal’s body weight or body condition score.

Abstract

Seasonal reproduction restricts the offering of goat commodities across the year. Therefore, it is crucial to improve diverse strategies to induce the reproductive response in goats during the anestrus stage. The effectiveness of a short P4 + eCG-based estrus induction protocol during both the deep anestrous (March) or the reproductive transition period (June) upon the reproductive performance of crossbred dairy goats was assessed. Adult, anestrous, 24–30-month- old dairy crossbred (Saanen–Alpine–Nubian × Criollo) goats (n = 123) from two commercial herds and 10 sexually active goat bucks were used. Before the trials, the anestrous status of goats was confirmed. Then, goats were randomly allocated into two different experiments. In Exp. 1, we tested the effect of different doses (D) of intramuscular progesterone (P4; 10 or 20 mg + eCG (100 UI)) and type of breeding (TB), natural mating (NM), or artificial insemination (AI), on two commercial goat herds (H1 & H2), in March (deep anestrous). In Exp. 2, we evaluated the effect of D (P4; 10 or 20 mg + 100 UI eCG) in goats subjected to NM, and either during deep anestrous (March; M) or transitional anestrous (June; J), in two commercial herds. After breeding, conception and pregnancy were diagnosed with ultrasound scanning. The response variables were estrus induction (EI; %), estrus latency (EL; h), ovulation (OVP; %), ovulation rate (OR; units), fertility (FERT; %), and pregnancy (PREG; %). No differences (p > 0.05) in live weight (LW) and body condition score (BCS) occurred between herds in both trials. In Exp. 1, EI, EL, OVP, OR, FERT, and PREG were affected (p < 0.05) by the H–TB–D interaction, whereas in H1 + P4–20 combination had the highest (p < 0.05) EI, EL, and OVP values. Irrespective of TB, H1 had the largest (p < 0.05) OR, independently of TB or D. Also, the lowest (p < 0.05) OVP occurred in the AI + P4–10 group, while the AI had the lowest (p < 0.05) FERT, irrespective of D. FERT and PREG were two-fold higher (p < 0.05) in NM compared with AI. In Exp. 2, EI, EL, OVP, OR, FERT, and PREG were affected (p < 0.05) by the H–M–D interaction. In general, H2 + P4–10 had the lowest (p < 0.05) reproductive outcomes in March, whereas H1 had the largest (p < 0.05) values in either month. No differences (p > 0.05) between P4 doses occurred for EI, OVP, OR, FERT, and PREG. Yet, the largest (p < 0.05) EL occurred with P4–20 in June. No correlations (p > 0.05) occurred between LW and all the reproductive variables. BCS was positively correlated (p < 0.05) with EI (0.34), OVP (0.44), OR (0.58), and PREG (0.20). Also, positive correlations (p < 0.05) occurred between EI with EL (0.83), OVP (0.80), OR (0.64), and PREG (0.56); EL with OVP (0.58), OR (0.44), and PREG (0.42); OVP with OR (0.79) and PREG (0.70), as well as OR and PREG (0.63). Results of these studies confirm a multidimensional response regarding the effectiveness of P4 + eCG for estrus induction in goats mainly modulated by a specific time within the anestrous season, or even by specific management or a particular environment at the herd level (H1), although quite remarkably independent of the animal’s LW or BCS at herd level. Moreover, the best reproductive outcomes occurred with NM in June. The most reproductive variables were similar using either 10 or 20 mg P4 + 100 IU eCG, giving the possibility to lessen the scale in the use of exogenous hormones while obtaining acceptable out of season reproductive response.

Short communication: reproductive response to concentrate supplementation of mixed-breed goats on rangeland

The effect of concentrate supplementation to crossbred goats on rangeland during the dry period on their reproductive performance was investigated. Goats were assigned into two groups: a concentrate supplemented (S; n = 91) group and an unsupplemented (UNS; n = 118) group. S goats received 350 g/day of concentrate per head, 30 days prior to breeding (flushing in winter) and 30 days during the last trimester of pregnancy. UNS goats presented a lower (P < 0.01) liveweight at the onset of the breeding period than did the S group (38.2 ± 3.7 vs. 44.4 ± 3.6 kg). Average daily gains during pregnancy were higher (P < 0.01) in the S group than UNS goats (15.5 ± 1.2 vs. - 0.5 ± 5.1 g/d). S goats had a higher (P < 0.01) kidding rate (87.1%) than the UNS goats (54.7%). Litter size for UNS and S goats was 1.39 and 2.00, respectively (P < 0.01). Serum triiodothyronine, tetraiodothyronine, and cortisol concentration at the end of the flushing period were not affected by concentrate supplementation. Serum glucose (88.7 ± 3.8 vs. 95.7 ± 5.3 mg/dL), total protein (6.9 ± 1.1 vs. 8.2 ± 1.2 mg/dL), and blood urea nitrogen (17.1 vs. 21.0 ± 4.3 mg/dL) concentrations were lower for UNS goats as compared with S goats. In conclusion, concentrate supplementation in crossbred goats on rangeland markedly improved body mass changes during gestation and the reproductive performance, which implies that malnutrition is a major barrier affecting fertility of goats and liveweight of kids in this rangeland.

D-dimer levels and risk of recurrence following provoked venous thromboembolism: findings from the RIETE registry

BACKGROUND

Patients with venous thromboembolism (VTE) secondary to transient risk factors may develop VTE recurrences after discontinuing anticoagulation. Identifying at-risk patients could help to guide the duration of therapy.

METHODS

We used the RIETE database to assess the prognostic value of d-dimer testing after discontinuing anticoagulation to identify patients at increased risk for recurrences. Transient risk factors were classified as major (postoperative) or minor (pregnancy, oestrogen use, immobilization or recent travel).

RESULTS

In December 2018, 1655 VTE patients with transient risk factors (major 460, minor 1195) underwent d-dimer measurements after discontinuing anticoagulation. Amongst patients with major risk factors, the recurrence rate was 5.74 (95% CI: 3.19-9.57) events per 100 patient-years in those with raised d-dimer levels and 2.68 (95% CI: 1.45-4.56) in those with normal levels. Amongst patients with minor risk factors, the rates were 7.79 (95% CI: 5.71-10.4) and 3.34 (95% CI: 2.39-4.53), respectively. Patients with major risk factors and raised d-dimer levels (n = 171) had a nonsignificantly higher rate of recurrences (hazard ratio [HR]: 2.14; 95% CI: 0.96-4.79) than those with normal levels. Patients with minor risk factors and raised d-dimer levels (n = 382) had a higher rate of recurrences (HR: 2.34; 95% CI: 1.51-3.63) than those with normal levels. On multivariate analysis, raised d-dimers (HR: 1.74; 95% CI: 1.09-2.77) were associated with an increased risk for recurrences in patients with minor risk factors, not in those with major risk factors.

CONCLUSIONS

Patients with raised d-dimer levels after discontinuing anticoagulant therapy for VTE provoked by a minor transient risk factor were at an increased risk for recurrences.

Characterization of small-scale dairy farms and its relation to water use efficiency in the Mexicali Valley, Mexico

A survey was completed to determine water use by small-scale dairy farms in Mexicali Valley of Mexico and to associate it with dairy production parameters. Mexicali Valley surrounds the capital city of the state Baja California, Mexicali. Sixty-one smallholders were interviewed in person in this rural area of northwestern Mexico. On average, small dairy holders had more than 20 years of experience and were ~ 55 years of age; people working on their farms are especially relatives. A low percentage was literate (20%), and they belong to a local dairy association. Milk yield/cow/year does not reach 4000 kg of milk and 75% of producers do not follow a defined management program for their cattle. Hand-milking is still practiced by 27% of the producers, and there is a general lack of infrastructure to maintain milk in a refrigerated state so that there is a very high risk of zoonotic diseases. Water use efficiency (WUE) was linearly correlated (P < 0.05) with total irrigated area, but not with animal production parameters. Regression equations constructed to explain WUE exhibited low adjustment, and WUE was not associated (P > 0.05) with milk yield. Small dairy producers in Mexicali Valley are in a generally poor situation with low water use practices; however, required more government support to increase their benefits from this livestock activity.

Factors influencing English Bulldog bitch fertility after surgical uterine deposition of fresh semen

The aim of this study was to evaluate the effect of body weight, oxytocin deposition in the uterus at artificial insemination (AI), vaginal cytology, serum progesterone (P₄) concentration at AI, semen volume and total sperm cells per AI on whelping rate and litter size of English Bulldogs bitches following intrauterine surgical semen deposition. Seventy-eight English Bulldog bitches were artificially inseminated via semen infusion (number of sperm cells inseminated 300-2500 × 10⁶) at the uterine body with fresh semen without extender and under general anesthesia. Whelping rate was greater (P < 0.05) in bitches with >23 kg than bitches with <23 kg (83.9 vs 63.8%). Whelping rate was greater (P < 0.01) in bitches with >75% vaginal cornified epithelium at AI (85.1%) than animals with <75% cornified epithelium (51.6%). Whelping rates were influenced (P < 0.01) by the semen volume at AI (54.3% vs 86.1% for bitches receiving <4 mL or >4 mL of semen). Litter size was larger (P < 0.05) in bitches >23 kg than lighter animals (3.72 ± 1.79 and 2.30 ± 1.46 pups per litter, respectively). Litter size was not influenced by sperm concentration, semen volume, vaginal cytology, serum P₄ concentration and infusion of oxytocin in the uterus at AI (P > 0.1). The results of this study indicate that increasing body weight of English Bulldog bitches is related to higher whelping rates and larger litter size. Also, >75% of superficial cornified vaginal cells (squamous) at AI and >4 mL semen volume maximize whelping rates in this breed of dogs.

Factores de riesgo a nivel de establo asociados con el desempeño reproductivo en el sistema de producción de leche a pequeña escala en México

La rentabilidad de los establos lecheros está fuertemente asociada con el desempeño reproductivo. Por lo tanto, la identificación de factores de riesgo que comprometen este desempeño es primordial para implementar estrategias que mejoren la productividad. En este estudio, se probaron los efectos del uso de inseminación artificial (IA), hatos grandes y seroprevalencia alta de enfermedades infecciosas reproductivas sobre el desempeño reproductivo. Se incluyeron al estudio 52 establos (10-100 vacas; 959 lactaciones) registrando eventos reproductivos durante 18 meses (partos 2011-2012). Las seroprevalencias de neosporosis, rinotraqueitis infecciosa bovina (IBR) y diarrea viral bovina (BVD) se registraron en cada establo. Se utilizaron análisis de regresión logística múltiples para determinar el grado de asociación (razón de momios, OR) entre factores potenciales de riesgo y variables reproductivas. Establos ≥33 vacas y seroprevalencia alta de neosporosis fueron factores de riesgo para Asistencia al Parto (OR 1.5 y 2.3, respectivamente). Seroprevalencias altas de IBR y BVD fueron factores de riesgo para Días a Primer Servicio>70 Días en Leche (DPS>70, OR 1.3 y 1.9, respectivamente). La IA fue un factor de riesgo común para DPS>70 y Días Abiertos>110 Días en Leche (OR 2.4 y 1.3, respectivamente). Establos ≥33 vacas fue un factor de riesgo para Vacas No Gestantes al Primer Servicio (OR 1.7). En conclusión, la IA, establos ≥33 vacas y seroprevalencias altas de neosporosis, IBR y BVD son factores asociados al desempeño reproductivo en establos de producción de leche a pequeña escala en varias regiones geográficas de México.

The Opuntia effect and the Reactivation of Ovarian Function and Blood Metabolite Concentrations of Anestrous Goats Exposed to Active Males

Simple Summary

We evaluated the potential supplementation effect of protein enriched Opuntia cladodes, the flat leaf-like steam of cactus species (PEO), upon changes of blood metabolites, estrus induction, estrus latency, and ovulation rate in anestrous goats exposed to sexually active males. We observed that PEO positively influenced reproductive outcomes without changes in blood metabolites. Our results highlight the importance that bio-fortified Opuntia cladodes supplementation exerts on anestrous goats exposed to the male effect as an option to improve not only the out-of-season reproductive efficiency of goats but to enhance the sustainability of marginal, extensive and semi-arid goat production systems.

Abstract

The effect of protein enriched Opuntia cladodes supplementation upon changes of serum total protein, urea, cholesterol, glucose as related to estrus induction (EI%), estrus latency (EL, h), and ovulation rate (OR, units) in adult anestrous goats exposed to the male effect was evaluated. In late April, anestrus goats (n = 45, 25° N) homogeneous regarding live weight (LE; 43.8 ± 1.6 kg) and body condition score (BCS; 2.3 ± 0.1 units) were randomly assigned to: (1). Protein-enriched Opuntia (PEO; n = 15; 29.8% CP, 2.2 Mcal ME kg⁻¹), (2). Non-enriched Opuntia (NEO; n = 15; 6.4% CP, 2.1 Mcal ME kg⁻¹), and (3). Control (CON; n = 15). NEO and PEO goats were individually supplemented with cladodes (160 g d⁻¹; 0900–1000 h), thereafter all groups grazed in a marginal rangeland (1000–1800 h). Neither LW (p > 0.05) nor BCS (p > 0.05) differed among groups, yet an increased (p < 0.05) EI % (100, 57, 42 ± 0.16%), EL h (62, 60, 32 ± 4.2 h), and OR (1.33, 0.71, 0.43 ± 0.23 units) occurred in PEO and NEO vs. CONT, respectively. However, neither blood metabolites differed among groups nor a treatment x time interaction occurred. Peri-breeding protein enriched Opuntia cladodes supplementation of anestrous goats exposed to active males increased (p < 0.01) reproductive outcomes during the non-breeding season.

Activation of Th lymphocytes alters pattern expression and cellular location of VIP receptors in healthy donors and early arthritis patients

Vasoactive Intestinal Peptide (VIP) is an important immunomodulator of CD4⁺ cells in normal and pathological conditions, which exerts its anti-inflammatory and immunomodulatory actions through VPAC receptors, VPAC₁ and VPAC₂. Only a decrease in the expression of VPAC₁ mRNA on Th cells upon activation has been reported. Thus, the deepening in the knowledge of the behavior of these receptors may contribute to the design of new therapies based on their activation and/or blockade. In this study, we describe the expression pattern, cellular location and functional role of VIP receptors during the activation of human Th cells in healthy conditions and in early arthritis (EA). The protein expression pattern of VPAC₁ did not change with the activation of Th lymphocytes, whereas VPAC₂ was up-regulated. In resting cells, VPAC₁ was located on the plasma membrane and nucleus, whereas it only appeared in the nucleus in activated cells. VPAC₂ was always found in plasma membrane location. VIP receptors signaled through a PKA-dependent pathway in both conditions, and also by a PKA-independent pathway in activated cells. Both receptors exhibit a potent immunomodulatory capacity by controlling the pathogenic profile and the activation markers of Th cells. These results highlight a novel translational view in inflammatory/autoimmune diseases.

Relationships of body surface thermography with core temperature, birth weight and climatic variables in neonatal lambs born during early spring in an arid region

The main cause of death in newborn lambs is hypothermia, so is necessary to identify the factors affecting variations in body surface temperatures of sheep neonates because approximately 60% of their body heat losses occur through the skin. This study aimed to establish relationships among body surface thermography from different regions with rectal temperature (RT), birth weight (BW) and climatic variables in hair breed newborn lambs during early spring in an arid region. Data of body surface temperatures measured by infrared thermography (entire head, eye, muzzle, ear, entire body, shoulder, rump, loin, right flank, belly and leg), RT and BW were collected at 0, 12 and 24 h post-lambing in 85 lambs born in early spring. Relative humidity [RH], temperature [Te] and temperature-humidity index [THI] were also recorded. RT was not correlated with surface temperatures at 0 and 24 h, but it was at 12 h with all of them (0.36 ≤ r ≤ 0.44). BW and some surface temperatures were negatively correlated at 0 and 24 h (-0.24 ≤ r ≤ -0.30), but positively at 12 h (0.25 ≤ r ≤ 0.27). All surface temperatures were positively correlated (0.51 ≤ r ≤ 0.85) with Te and THI in the three sampling times. Principal component (PC) analysis showed that PC1 explained the majority of the variance (71-72%), followed by PC2 (8-9%) at 0, 12 and 24 h. Body surface temperatures increased as Te and THI also increased, but decreased with the increase in HR. In conclusion, under early spring environment (predominantly cold), the variations in body surface temperatures of hair sheep neonates were more closely related to climatic variables than to RT and BW. Thermography proved to be an effective tool to determine body heat loss by radiation in skin of neonate lambs.

Nanoparticles in Equine Nutrition: Mechanism of Action and Application as Feed Additives

Several concerns exist regarding horse rearing such as environmental pollution, antibiotics resistance, digestive disorders, mycotoxins contamination of animal feed, gut health management, and improvement of feed efficiency. Nanoparticles have the potential to address these issues and thus could be used as feed additive. Citrate reduces and stabilizes gold nanoparticles, alongside biosynthesized silver nanoparticles have the potential to prolong and improve digestive enzyme activity, which would enhance starch digestibility in the stomach. Zinc oxide and selenium nanoparticles could be used to improve feed digestibility and volatile fatty acids production. Magnesium oxide, silver, and copper nanoparticles exhibit strong antimicrobial activity against gram-positive and gram-negative microbes and weaken the biofilm formation of the microbial community. Calcium, zinc, and silver nanoparticles could be used to prevent periodontal disease in horses. In addition, silver nanoparticles may be applied as antifasciolitics and potentially against other gastrointestinal parasites. Environmental concern of equines could be addressed by using cerium oxide, silver, and cobalt nanoparticles to reduce methane emission and zinc oxide could help to reduce fecal mineral output. Fullerol C₆₀[OH]_24, a honey-derived silver nanoparticle and zinc oxide nanoparticles exhibit attractive antibacterial properties because of increased specific surface area as the reduced particle enhance unit surface reactivity. Gut health management of equines could be solved with nanoparticles because of the ability of ferrous oxide and copper nanoparticles to improve microbial growth, whereas zinc oxide improves villus height, crypt depth, and villous surface area. It is required to explore in depth the beneficial effects of these nanoparticles as a novel area in the equine industry's both in vitro and in vivo before recommendation to equine owners.

Ovarian response is not affected by the stage of seasonal anestrus or breed of goats when using a progesterone injection plus human chorionic gonadotropin-based protocol

The aim of this study was to evaluate the effect of the stage of seasonal anestrus and breed on ovarian response in non-estrous cycling goats using a progesterone (P4) injection plus human chorionic gonadotropin (hCG)-based protocol. In Experiment 1, non-estrous cycling local Mexican goats were treated with 20 mg of P4 plus 100 IU of hCG injections 24 h apart during April (early anestrus, n = 13) or June (late anestrus, n = 12). The estrous response, interval from hCG-to-estrus, and interval to ovulation were not affected by season (P > 0.05). In addition, the size of the follicle from which ovulation occurred and the size of the corpus luteum were not different between the two stages of seasonal anestrus (P > 0.05). In Experiment 2, the estrous response was compared between multiparous non-estrous cycling local Mexican (n = 18) and Alpine (n = 19) goats in which stage of the estrous cycle was synchronized using the same P4+hCG protocol as in Experiment 1. Neither the onset of estrus nor the time of ovulation differed between breeds, and the estrus-to-ovulation interval also was similar for both breeds (P > 0.05). The diameter of the dominant follicle at the time of ovulation was similar between local and Alpine goats (P > 0.05). In addition, the pregnancy rate was not different for both local and Alpine goats (P > 0.05). In conclusion, results of this study indicate that the stage of seasonal anestrus or breed do not modify estrous and ovarian response in non-estrous cyclic goats synchronized with a P4 injection plus hCG-based protocol.

The impact of hair coat color on physiological variables, reproductive performance and milk yield of Holstein cows in a hot environment

Vulnerable animals to heat stress have been described as ones with dark or black hides due to increasing absorption of solar radiation. The effect of coat color in pluriparous contemporary Holstein cows in a hot environment (mean annual temperature 24.6 °C), on body surface temperature (infrared thermography), physiological and hematological variables as well as milk yield and reproductive performance was assessed using 178 Holstein pluriparous cows (74 predominantly white and 104 predominantly black). Data were collected in the morning and afternoon in July (mean temperature-humidity index 82 units). Body condition score at mid-lactation (128 ± 32 days in milk at the start of the experiment) was higher (P < 0.01) in predominantly white than in black cows (3.3 vs. 3.2). Respiration rate did not differ between groups (72 ± 23 vs. 73 ± 20 breaths/min for white and black cows, respectively, sampling time combined). In contrast, rectal temperature of black cows was 0.1 °C higher (P ≤ 0.01) than white cows, regardless of sampling time. The only significant hematologic change was a slight increase in mean corpuscular volume in black cows (54.7 fL, P < 0.01) compared to white cows (53.8 fL), but it remained within the reference range. Differences due to coat color did not alter body surface temperatures at any time of the day. Conception rates, services per conception, calving intervals and fetal losses were not associated with hair coat color, but cows with predominantly white coat produced 394 kg more (P < 0.01) fat-corrected milk in 305 days compared to cows with predominantly black coat. It was concluded that in this hot-arid environment with cows housed in facilities with extensive cooling, black hair coat moderately reduces 305-d milk yield without affecting milk composition, body surface temperature, and reproductive performance.

Milk yield and hair coat characteristics of Holstein cows in a hot environment

This study was conducted to evaluate the effects of hair coat characteristics on thermophysiological variables and body surface temperatures (BST), measured with infrared thermography, as well as milk yield of Holstein cows in a hot environment. Physiological and milk yield variables were assessed using 103 pluriparous Holstein cows. Also, hair angle (HA), density of hair coat (D), diameter of hair (HD), hair length (HL), weight of hair coat (Wt), and coat thickness (CT) were recorded. Biplot analysis (principal components analysis) revealed that HL was closely associated with Wt, CT, and HD and all these variables had a positive association with rectal temperature. Both CT and HL were found to be negatively associated with shoulder and neck temperature; tympanic temperature showed no association with BTS. Cows with short hair coat (length < 17 mm) did not produce more milk in 305 days than cows with longer hair coat (9673 ± 1604 vs. 9277 ± 817; P = 0.12). On the other hand, milk fat percentage at the middle of lactation was higher (P < 0.01) in cows with longer hair relative to cows with coat hair < 17 mm (3.71 vs. 3.35%, respectively). In conclusion, physical characteristics of the coat of Holstein cows were not associated with the 305-day milk yield but cows with longer hair produced a greater milk fat percentage at the middle of lactation compared to cows with short hair.

Thermoregulatory response to outdoor heat stress of hair sheep females at different physiological state

Forty Dorper × Pelibuey sheep females were used to evaluate the effects of physiological state on physiological variables and serum concentrations of metabolites, thyroid hormones, and electrolytes under outdoor heat stress conditions. Females were selected as follows (n = 10 per group): weaning ewe lambs (WEL; 3 months old), replacement nulliparous ewes (RNE; 8 months old), non-pregnant and non-lactating multiparous ewes (NME; 3-4 years old) and lactating multiparous ewes (LME; 3-4 years old). While physiological variables were measured both morning and afternoon, blood samples were collected before feeding in the morning to determine all blood components. Three contrasts were constructed: (1) WEL vs. older ewes, (2) RNE vs. multiparous ewes, and (3) NME vs. LME. Compared with older ewes, WEL had higher (P < 0.01) rectal temperature (RT) and hair coat temperatures through the day, and also higher (P < 0.01) respiratory rate (RR) only in the afternoon. Serum levels of glucose and cholesterol were lower (P ≤ 0.02) in WEL than in older ewes. Nulliparous ewes compared with multiparous had always similar RT but higher (P ≤ 0.05) hair coat temperatures in most of the body regions by the morning and higher (P < 0.01) RR, without difference for hair coat temperatures in the afternoon. Only serum glucose (P = 0.07) and urea nitrogen (P < 0.01) levels were affected by parturition number, being lower in multiparous ewes. Regarding the effect of lactation, while RR was unaffected, afternoon RT and hair coat temperatures in most of the body regions through the day were higher (P ≤ 0.03) in lactating ewes. In addition, LME had lower (P < 0.01) serum levels of glucose, cholesterol, and urea nitrogen, but higher (P = 0.02) triiodothyronine levels than NME. In conclusion, ewe lambs and lactating ewes were less tolerant to heat stress, while nulliparous and multiparous ewes showed similar thermoregulatory ability.

Variaciones en las respuestas termoregulatorias de ovejas de pelo durante los meses de verano en un clima desértico

Se confinaron 10 ovejas multíparas Katahdin × Pelibuey, color blanco, no gestantes y no lactantes, para evaluar las variaciones diurnas de variables fisiológicas y concentración de algunos metabolitos sanguíneos a través de los meses calientes de verano (junio-septiembre), en una región desértica del noroeste de México. Las concentraciones de metabolitos se midieron a las 6 y 18 h y las variables fisiológicas a las 0, 6, 12 y 18 h durante cuatro días de cada mes (mediciones semanales). Los promedios para temperatura ambiental e índice de temperatura-humedad durante el verano fueron 33.6 ºC y 78.6 unidades, respectivamente, siendo agosto el mes más caliente. No cambió (P>0.05) el peso vivo y la condición corporal a través de los meses de verano. La temperatura rectal en agosto fue menor (P<0.05) entre 0 y 12 h, y mayor (P<0.05) a las 18 h comparado con los otros meses. La frecuencia respiratoria descendió (P<0.05) a las 6 h en todos los meses, pero a las 0 y 18 h fue mayor (P<0.05) en agosto que en los otros meses. Se observaron mayores (P<0.05) concentraciones de glucosa y menores (P<0.05) concentraciones de colesterol y triglicéridos en junio y julio con relación a agosto y septiembre. Se concluye que las ovejas de pelo mantienen homeotermia durante los meses de verano en regiones desérticas por cambiar el ritmo diurno de sus variables fisiológicas y metabolitos, de acuerdo con la intensidad del estrés calórico de cada mes.

Risk factors associated with reproductive performance in small-scale dairy farms in Mexico

Several studies suggest that reproductive performance in small-scale dairy farms is low reducing the farms' profitability. Therefore, identifying risk factors associated with low reproductive performance is a key step to implement an improved reproductive management program. Accordingly, the aim of the present study was to identify the main risk factors affecting the reproductive performance of cows in small-scale dairy farms. Ninety-six dairy farms were incorporated into this study, and data from 1263 lactations were collected with different events as potential risk factors. Logistic regression models were used to assess the association (odds ratio, OR) and impact (population attributable fraction, PAF) between the potential risk factors and the reproductive variables. The main risk factors associated with assisted calving were male calf and primiparous cows (OR = 1.7, PAF = 0.315 and OR = 1.5, PAF = 0.131, respectively), while for retained fetal membranes (RFM) were assisted calving and abortion (OR = 4.5, PAF = 0.440 and OR = 8.1, PAF = 0.239, respectively). The main risk factors for days to first service over 70 days in milk were low body condition score at calving (BCS ≤ 2.5) and primiparous cows (OR = 2.2, PAF = 0.285 and OR = 1.4; PAF = 0.096, respectively), while for days open over 110 days in milk were low BCS at calving (BCS ≤ 2.5) and primiparous cows (OR = 1.7, PAF = 0.213 and OR = 1.4; PAF = 0.096, respectively) The main risk factor for non-pregnant cows at first service was RFM (OR = 1.7; PAF = 0.059). In conclusion, assisted calving, male calf, BCS ≤ 2.5 and RFM were the main risk factors associated with reduced reproductive performance in small-scale dairy farms in tropical and subtropical regions of Mexico.

The use of female estrogenized goats as sexual stimulator of crossbred dairy males subsequently exposed to acyclic goats during two phases of the anestrous season

This research evaluated the possible influence of exposure of male goats to estrogenized female goats ("female effect") upon males' sexual behavior [appetitive (ASB) & consummatory (CSB)], as well as the induction of reproductive activity of crossbred dairy female goats exposed to such treated males ("male effect") during the early and deep anestrous periods. Crossbred dairy adult male goats (n = 12; 24-48 mo. old) and 80 anovulatory crossbred dairy adult female goats (34-50 mo. old) were used during two experimental periods: March to April and April to May. First, males were separated into four groups (n = 3 each), roughly homogeneous regarding body weight and body condition score and randomly assigned to four experimental groups. The first two groups included males + estrogenized females, then such males were exposed to anestrous females either during March (group 1: three males; 20 females; EFEM-MAR), or during April (group 2: three males; 20 females; EFEM-APR). The second two groups were respective control groups: Males + non-treated-anestrous females, and then such males exposed to acyclic females either during March (group 3: three males; 20 females; CONT-MAR) or April (group 4: three males; 20 females; CONT-APR). Once the male-to-female contact was established, both odor (ODT) and behavior (BEHT) tests (2 d × 2 h) were performed during both anestrous periods. On day 10 after introduction of the males, in both anestrous periods, one ultrasonography scanning ("US") was performed to quantify the presence, number and size of corpus luteum (US-CL) to determine the effectiveness of the "male effect" and indicators of ovarian activity. Then, on day 45 after introduction of the males, a second US was performed to evaluate pregnancy rate (US-PREG). The EFEM-males, regardless of the phase of the anestrous cycle, had an increased (P < 0.05) odor intensity with respect to the control groups. In addition, while an increased (P < 0.05) ASB occurred in the EFEM-males, no CSB differences (P > 0.05) arose when treatments were compared, neither in March-April nor in April-May. The EFEM-males exposed to acyclic goats in March-April (i.e. early anestrous period), promoted not only the largest estrus and ovulatory responses (P < 0.05), but also the largest pregnancy rate (P < 0.05) in these previously anestrus goats, suggesting that in April-May (i.e. profound anestrous), the presence of active males was not enough to completely suppress cyclic reproductive arrest. This study generates interesting out-of-season reproductive outcomes in a goat population with a large proportion of highly seasonal dairy breeds (i.e. Alpine, Saanen and Toggenburg), augmenting the possibility to expand milk production and the economic income of goat producers across the year. Besides, this practice may serve as an interesting reproductive tool to increase the sustainability of marginal goat production systems under semiarid conditions.

Effects of pre-lambing maternal energy supplementation on post-weaning productive performance and thermoregulatory capacity of heat-stressed male lambs

Nutritional requirements of sheep during late gestation increase as a consequence of high fetal growth, mammary tissue development and colostrum synthesis. While prepartum energy supplementation is a nutritional strategy to improve lamb postnatal performance in thermoneutral environments, this has not been studied under heat stress. This study aimed to evaluate effects of maternal energy supplementation during the last third of pregnancy on post-weaning feedlot performance and thermoregulation capacity of heat-stressed male lambs born from multiple births. Twenty Dorper x Pelibuey entire male lambs with initial body weight of 18.2 ± 0.4 kg, aged 2.7 mo (weaned) and born in multiple pregnancies were used in a 32 d feeding study. Treatments were based in the prenatal origin of the lambs: 1) ewes fed 100 (n = 10, Control) and 2) 125% (n = 10, Supplemented) of metabolizable energy requirements from day 100 of gestation to lambing. Lambs were housed outdoor in individual pens under summer environment conditions in an arid region (temperature = 36 ± 4.4 °C and temperature-humidity index = 81 ± 3.9 units). Overall feedlot performance was not affected by pre-partum maternal feeding, although lower (P = 0.04) growth rate and feed efficiency occurred during the last 8 d of the study in lambs born from supplemented ewes. Rectal temperature, respiratory rate and hair coat temperature during daytime were unaffected by prepartum supplementation. Serum concentrations of glucose, cholesterol, urea, total protein and thyroid hormones were similar between lambs born from control and supplemented ewes. It is concluded that, in hair sheep breeds, prepartum energy supplementation did not alter overall post-weaning productive performance and thermoregulation capacity of heat-stressed male lambs that were born in multiple pregnancies.