The objective of this study was to determine the effects of the administration of recombinant bovine somatotropin (rbST) throughout lactation to high-yielding subfertile (conception > 270 days postpartum) Holstein cows undergoing extended lactations (≥480 d) on milk production and reproductive performance. The study used two large adjacent commercial herds with similar management in a hot area of northern Mexico (25° N). Cows in one herd (n=2341) received a 500-mg dose of rbST every 14 d until dried off, starting 60 days postpartum. The other herd served as control (n=984). Across parity, rbST-treated cows produced 20% greater milk yield than control cows in 305-d lactations. Across parities, milk yield from 305 d postpartum to the end of lactation was 2734 kg higher in rbST-treated cows than control cows. Across parities rbST-treated cows produced 4777 more kg of milk during the entire lactation (mean 605 d) than the control group (mean 572 d). Conception rates (CR) at first service were only 3.2% and 5.9% (p<0.05) for control and rbST-treated cows, respectively. Overall CR was 43.5% and 61.6% (p<0.05) for control and treated cows, respectively. Control cows required 2.4 more (p<0.01) services per conception than rbST-treated cows. It was concluded that in this hot environment, the use of rbST suits dairy producers because it substantially improves both milk yield and reproductive performance in subfertile high-yielding Holstein cows. By markedly increasing lactation length and lactation persistency farm efficiency is greatly improved due to extended herd life.

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.

Considering a circular economy perspective, this study evaluates the possible effect of targeted short-term supplementation with Withania somnifera L. (WS; Ashwagandha) on ram’s seminal quality, socio-sexual behaviors, and blood constituents. Black Belly rams (n = 20) received a basal diet comprising feed-leftovers from dairy cows in the north-arid Mexico (i.e., Comarca Lagunera CL). The experimental units, with proven libido and fertility, were homogeneous in terms of age (3.41 ± 0.21 yr.), live weight (LW; 53.8 ± 3.3 kg), body condition (BC; 2.96 ± 0.01 units), initial sperm concentration (2387 ± 804 × 10⁶), and viability (23.9 ± 15.6%). Rams were randomly assigned during the transition reproductive period (i.e., May to Jun; 25° NL) to three treatment groups: non-supplemented control group (CONT; n = 6), low WS-supplemented (LWS; i.e., 100 mg kg LW⁻¹ d⁻¹ × 40 d; n = 7), and high-WS-supplemented (HWS; i.e., 200 mg kg LW⁻¹ d⁻¹ × 40 d; n = 7). The basal leftover diet was offered twice daily (0700 and 1600 h); the experimental period (EP) lasted 47 d. No differences (p > 0.05) among treatments occurred regarding LW and BCS at the onset of the EP. Whereas the greater scrotal circumference (SCRC, cm) arose in the LWS and CONT rams, an increased ejaculated volume (VOLEJA, mL) occurred in the WS-rams. A total of 5/9 (i.e., 55%) appetitive and 3/3 (i.e., 100%) consummatory sexual behaviors favored (p < 0.05) the WS-rams, particularly the HWS rams, towards the final EP. The same was true (p < 0.05) regarding the hemogram variables white blood cell count (×10⁹ cells L⁻¹), hemoglobin concentration (g dL⁻¹), and medium corpuscular volume (fL). This study, based on a rethink–reuse–reduce enquiry approach, enabled connectedness between two noteworthy animal systems in the CL: dairy cows and meat sheep schemes. Certainly, the use of dairy cow feed-leftovers aligned with the short-term supplementation with WS promoted enhanced testicular function, augmented seminal volume, and an increased sexual behavior in Black Belly rams in northern Mexico. Finally, while our research outcomes should enhance not only the resilience and sustainability of sheep production and the well-being of sheep-producers and their families, it may also embrace clinical translational applications.

The possible effect of body condition score (BCS) on ovarian function, sexual behavior, (i.e., females and males; appetitive and consummative), estrus, ovulation, and reproductive performance was investigated in crossbred dairy goats under extensive conditions. Based on their BCS, female goats (n = 48) were divided into two experimental groups, either with a low (LG; 1.0 ± 0.2 units; n = 26) or with a high BCS (HG: 2.5 ± 0.9 units; n = 22). Bucks n = 4; cc = 2.5. Female sexual behavior (i.e., acceptance of anogenital sniffing and approach, flight, and tail wagging) was higher in the HG (p < 0.05). In addition, bucks exposed to HG goats showed more approach and mounting attempts (p < 0.01). There were no significant differences (p > 0.05) between the groups in either the follicular diameter or size. Interestingly, although follicular volume, pregnancy rate, kidding rate, and total number of kids born alive were higher in the HG goats (p < 0.05), there were no significant differences (p < 0.05) in fetal mortality and prolificacy between the HG and LG goats. In addition, the response variables of female ovulation, total number of corpus luteum, ovulation rate, corpus luteum diameter, and luteal tissue volume were more favorable in the HG goats (p < 0.05). Our research results demonstrate that a higher BCS improves not only the reproductive responses, but also sexual behavior (i.e., female and male). Larger ovarian structures, higher ovulation rates, higher pregnancy and kidding rates, and higher prolificacy were observed in the HG goats managed under a marginal semiarid extensive production system.

Colostrum is the first mammary secretion and is the only way in which calves can obtain passive immunity. This study aimed to correlate the quality of colostrum from high-yielding dairy cows using either a colostrometer or Brix digital refractometry (°Bx). Samples (N=340) of colostrum were taken from cows and analyzed with a colostrometer and Brix refractometry. A linear regression was performed, the coefficient of determination (R2) was calculated. All statistical analyzes were done with the SPSS 25.0 statistical package. Means with colostrometer were 87.94±110, while with Brix refractometer they were 26.19±18, with R2 0.706 and a P<0.0001. In conclusion, the refractometer and the colostrometer are effective methods to determine immunoglobulins. Brix refractometer had an acceptable correlation, which could be a useful tool for verifying the colostrum’s quality next to the cow. http://dx.doi.org/10.21929/abavet2024.5 e2021-82 https://www.youtube.com/watch?v=Lw5YXZU0af8 El calostro es la primera secreción mamaria y es la única forma en la cual las becerras adquieren inmunidad pasiva. El objetivo de este estudio es determinar la correlación de la calidad del calostro de vacas lecheras de alta producción medido con calostrómetro y refractometría digital de grados Brix (°Bx). Se tomaron 340 muestras de calostro del mismo número de vacas y fueron analizadas mediante el calostrómetro y refractometría de °Bx. Se realizó una regresión lineal simple y se determinó el coeficiente de determinación (R²). Todo a través del paquete estadístico SPSS 25.0. La media de con calostrómetro fue de 87.94±110, mientras con refractometría Brix fueron de 26.19±18, con una R2 0.706 con un valor de P<0.0001. En conclusión, las lecturas de refractometría y el calostrómetro, son métodos efectivos en determinar las inmunoglobulinas. El refractómetro Brix tuvo una correlación aceptable, lo cual puede ser una herramienta fácil de verificación de calidad de calostro al pie de la vaca. http://dx.doi.org/10.21929/abavet2024.5 e2021-82 https://www.youtube.com/watch?v=Lw5YXZU0af8 http://dx.doi.org/10.21929/abavet2024.5 e2021-82 https://www.youtube.com/watch?v=Lw5YXZU0af8

Background: Hormonal treatments can influence hematological profiles through direct and indirect mechanisms in sheep’s. The aim was to evaluate the effect of administering equine or human chorionic gonadotropin (eCG, hCG, respectively) at 7 or 14 days post-mating on blood count values in early pregnancy of nulliparous ewes. Methods: A total of 63 ewes were used, which were randomly assigned to five experimental groups (EG): EG-eCG7 (300 IU of eCG, 7 days post-mating (DPM)), EG-hCG7 (300 IU of hCG 7 DPM), EG-eCG14 (300 IU of eCG 14 DPM), EG-hCG14 (300 IU of hCG 14 DPM) and; EG-Control (without hormonal treatment). Hematologic variables were determined on days 7, 14 and 28 DPM and included white blood cell count (WBCC), red blood cell count (RBCC), hematocrits (Ht), hemoglobin concentration (HbC), mean corpuscular hemoglobin (MCHb), mean corpuscular hemoglobin concentration (MCHbC) and medium corpuscular volume (MCV). An ANOVA and Pearson correlation were performed on the response variables. Result: The results showed differences in WBCC on day 7 between the EGs and between days for the EG-Control. The RBCC variable only showed differences between the days of the EG-eCG14. The Ht variable reported differences between the days of the EG-eCG14. Regarding HbC, differences were determined between the EGs for days 14 and 28, as well as between the days of the EG-hCG7. Additionally, positive and negative correlations were evidenced between the variables considered. Based on the above, it is concluded that in the first month of gestation, the variables WBCC, RBCC, Ht, HbC and MCV increase in pregnant ewes. The aforementioned contributes to determining ewes’ reproductive performance and improving their productive and reproductive parameters.