No abstract

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.

Background: Goats from subtropical and temperate latitudes show reproductive seasonality. For this reason, the products obtained from goats also shows the same seasonality, reducing the finances of goat keepers. Several studies have focused on reducing reproductive seasonality through the use of hormonal protocols based on progestogens, in addition to the use of equine chorionic gonadotropin (eCG) hormone, used for its double biological activity that ensures an optimal response to induce estrus and pregnancy in goats. The objective was to assess whether reduced doses of eCG are effective in inducing reproductive activity in anestrous goats. Methods: During the transition reproductive period (June), mix-breed Creole goats (n=39), were treated with intramuscular progesterone (P4), later, the experimental treatments, consisting in different doses (50, 100, 50+50 or 200 IU) of equine chorionic gonadotropin (eCG) were applied. After the application of the experimental protocols, the reproductive activity of the goats was evaluated. Result: This study shows that one dose of 100 IU of eCG effectively induced reproductive behavior in anestrous Creole goats towards the end of the seasonal anestrus. This protocol makes the use of exogenous hormones more efficient, with reduce doses, decreasing expenses and is practical use by goat producers.

The aim was to evaluate if 1-2 propanodiol plus calcium propionate (glycogenic precursor) supplementation during the transition period in high yielding dairy cows reduces metabolic and reproductive dysfunctions during early lactation. Cows (n=202) where divided into two homogeneous groups regarding number of lactations and body condition score. 1) Treated Group (GG; n=112) received 60g/cow/day  15d of a glycogenic precursor during the transition period. 2) Control Group (GC; n = 90) received no treatment. Postpartum levels of BHB (GG= 0.9±0.2 mmol/L vs GC =1.3±0.2 mmol/L; P < 0.05), and NEFA (GG= 0.6 ± 0.1 mEq/L vs GC = 0.8 ± 0.1 mEq/L; P < 0.05) were higher for GC. Likewise, GC-cows had a higher percentage of retained placenta (23% vs. 13%; P ≤ 0.06) subclinical ketosis (GG = 10%, GC = 56%; P < 0.05), and mastitis (GG = 8%, GC = 16%; P < 0.05). Metritis, dystocia, abortions, clinical ketosis, hypocalcemia and ruminal acidosis showed no differences. Administration of a glycogenic precursor during the transition period demonstrated a positive effect upon BHB and NEFA blood levels during early lactation. Also, levels of subclinical ketosis and retained placenta were reduced.

El objetivo del presente estudio fue evaluar la respuesta reproductiva de cabras cíclicas del norte de México (26ºN) sometidas a dos protocolos de administración de prostaglandinas (PG; 5 días vs 10 días) con el fin de sincronizar la respuesta estral. Se formaron 2 grupos de hembras caprinas adultas cíclicas de la raza Alpino francés. Al Grupo G5 (n=10), se les administró la primera inyección de PG (0.2 ml; 160 μg cloprostenol) el d -5 y el grupo G10 (n=10) recibió la primera inyección de PG el d -10. Ambos grupos recibieron la segunda inyección de PG el d 0 (noviembre 1). La respuesta reproductiva general después de la segunda inyección de PG fue similar (P>0.05) entre ambos tratamientos. Respuesta estral = 60% para ambos grupos, latencia al estro = 68h vs 52h, ovulación = 80% vs 60% (G5 vs G10, respectivamente; P>0.05). Debido a que no hubo diferencias entre grupos, la administración del tratamiento G5 parece ser una alternativa interesante para la utilización de un protocolo corto ya que generó una respuesta reproductiva importante.