Effect of nutritional supplementation upon pregnancy rates of goats under semiarid rangelands and exposed to the male effect.

The aim of this study was to evaluate possible effects of improved protein and energy diet upon reproductive outcomes of adult goats under marginal rangeland grazing conditions and exposed to the male effect during the anoestrous-dry season. Adult goats (Nubian × Criollo, nonpregnant, nonlactating, n = 160, 22° 50' N, 100° 59' W, 1,653 m) were randomly divided in two experimental groups: Control (CG; n = 80) and Supplemented (SG; n = 80). Both CG and SG goats were kept together during the day for ranging a semiarid rangeland while separated accordingly at night. SG goats were individually supplemented [400 g kg(-1) day(-1); 14% CP and 2.92 Mcal DE kg(-1)] during a 30-day period. Thereafter, both the CG [35.5 ± 0.94 kg LW, 1.95 ± 0.06 U, body condition score (BCS)] and the SG [39.5 ± 0.94 kg LW, 2.29 ± 0.06 BCS] were exposed to adult males (Nubian, n = 4, two per group) of proven libido and fertility and kept together at night (1700-0900) during a 42-day experimental breeding period. At the beginning of the breeding period, both LW (P < 0.001) and BCS (P < 0.001) were higher in the SG, which was also reflected in higher pregnancy rate (92.5 vs. 76.3%, P < 0.01). Nonetheless, both CG and SG depicted an increased abortion rate (52.5 vs. 41.9% P > 0.05), respectively. Results suggest that nutritional supplementation and the male effect were able to successfully invoke neurophysiological pathways to increase ovarian activity and to promote a uterine milieu prone to the establishment of pregnancy during the anoestrus season. However, the increased abortion rates observed in the study occurred irrespective of the nutritional regime offered during the premating stage. Therefore, there is a need to align the last third of gestation to the onset of the grazing season in order to increase reproductive and economic efficiency in those rangeland-based marginal goat production systems.

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.

Periconceptional nutrition with spineless cactus (Opuntia ficus-indica) improves metabolomic profiles and pregnancy outcomes in sheep.

We tested whether periconceptional nutrition with cladodes from the cactus, Opuntia ficus-indica, with or without protein-enrichment, improved the metabolomic profile and reproductive outcomes of adult female sheep. Sixty Rambouillet ewes of similar body weight were randomly allocated among three nutritional treatments that were fed during the breeding period (34 days): Control (Control; n = 20), Opuntia (Opuntia; n = 20) and protein-enriched Opuntia (E-Opuntia; n = 20). There were no effects of treatment on body weight but assessment of urine samples indicated that, for 76 metabolites, the Control and Opuntia groups differed completely (P < 0.05), whereas there was overlap between the Control and E-Opuntia groups. It appears that, in Opuntia-fed and Control-fed sheep, different functional groups are activated leading to changes in the metabolism of glucose, tyrosine, methane, and glycerolipids. Fertility and reproductive rate tended to be higher in the Opuntia (70% and 95%) and E-Opuntia (90% and 110%) groups than in the Control (55% and 65%), and an orthogonal contrast revealed the difference between Control and Opuntia to be significant for both reproductive variables (P < 0.05). We conclude that nutritional supplementation with Opuntia cladodes, with or without protein enrichment, increased fertility rate and reproductive rate of female sheep, without any accompanying increases in body weight. Our observations suggest that the reproductive responses to Opuntia do not simply reflect a response to good nutrition, but might be caused by specific metabolites/metabolomic pathways, perhaps by an activation of the metabolism of glucose, methane, tyrosine and glycerolipids. There are few reports relating these metabolomic compounds with the metabolism of the sheep, let alone with reproductive efficiency. The novelty of these discoveries suggests that we need further research into the mechanisms through which nutrition affects the reproductive system.

Intake of Spineless Cladodes of Opuntia ficus-indica During Late Pregnancy Improves Progeny Performance in Underfed Sheep.

The present study tested whether feeding ewes during the last third of pregnancy with cladodes of Opuntia (untreated or protein-enriched), as an alternative to alfalfa hay, would improve milk yield as well as the pre- and post-natal growth of their lambs. Sixty mature Rambouillet ewes and their progeny were randomly allocated among three nutritional treatments: (i) Control, fed alfalfa; (ii) Opuntia, fed untreated cladodes; (iii) E-Opuntia, fed protein-enriched cladodes (pre-treated with urea and ammonium sulphate). Birth weight did not differ among treatments (p > 0.05) but Control ewes produced more milk than both groups of Opuntia-fed ewes (p < 0.05). However, milk yield was not related to the growth of the progeny (p > 0.05) because lambs from E-Opuntia-fed ewes grew faster (p < 0.01) and were heavier at weaning (p < 0.05) than lambs from the other two groups. We conclude that Opuntia (with or without protein enrichment) can be used as an alternative to alfalfa hay for feeding ewes during the last third of pregnancy and therefore reduce production costs under extensive conditions in arid and semiarid regions. Moreover, protein-enriched Opuntia appears to improve postnatal lamb growth.

Relative roles of photoperiodic and nutritional cues in modulating ovarian activity in goats.

The objective of the current study was to evaluate the influence of nutrition and its interaction with the photoperiod on the ovarian activity of Criollo goats. In early February (22 degrees NL, anestrous season) goats were randomly assigned to the two experimental groups: high (HN; n=10) and low (LN; n=10) nutrition goats. The HN group was fed in mixed prairies with grass and clover (17.3-/+7.5% of crude protein, CP; 66.3-/+5.7% dry organic matter, DOM) and received 150 g of concentrate (12% CP) per goat and day. The LN group received only corn stubble (6.2-/+0.7% CP, 53.7-/+1.9% DOM). Serum progesterone (P(4)) and triiodothyronine (T(3)) concentrations were measured (RIA) at three selected periods of seasonal anestrous: early (8-24(th) March), mid (13(th) April - 3(rd) May) and late (26(th) May - 14(th) June) anestrous. Body weight, body condition and body condition index were determined at the beginning of the study and every 14 days. Body weight was positively correlated with serum T(3) (r=0.704; p<0.05). The percentage of cycling does during the three examined periods was higher (p<0.05) in the HN group than in the LN group (80 vs. 30%, 80 vs. 20%, and 60 vs. 10%, respectively). The high nutrition level increased reproductive activity of Criollo goats during all three periods of the anestrous season including deep anestrous.

Body condition and stage of seasonal anestrus interact to determine the ovulatory response after male biostimulation in anovulatory Criollo × Nubian goats.

The effect of goat nutritional condition on the response to biostimulation with sexually active males during different stages of anestrus was determined. Fifty-eight Criollo × Nubian females on high and low body mass index (BMI) diets were used. Each BMI group was divided into two for biostimulation with sexually active males during May (mid-anestrus) or July (transition period). Ovulatory responses to biostimulation were characterized from serum progesterone, as well as the delay for response (first and second ovulations followed by a normal length luteal phase, O-WNLP). The percentage of goats showing one O-WNLP was greater in the high BMI group than in the low BMI group and greater during the transition period than in the mid-anestrus. However, the interaction between factors revealed that the difference between BMI groups was only significant in the transition period and the difference between stages was only significant in goats with high BMI. Occurrence of a second O-WNLP tended to be greater in the high BMI group than in the low BMI group. Response delay was shorter in the transition period than in mid-anestrus. In conclusion, female nutritional status interacting with the stage of anestrus determined the ovulatory response to male biostimulation in crossbred Criollo goats.

Nutritional status influences reproductive seasonality in Creole goats: 1. Ovarian activity during seasonal reproductive transitions.

The objective was to determine the effect of body energy stores, evaluated by a body mass index (BMI), and food intake (FI), on the length of the anovulatory period and ovarian activity during the seasonal reproductive transitions in Creole goats. Non-pregnant, non-lactating Creole goats (n=28) were fed to induce two different BMI conditions: Greater (GBMI; n=15), and Lesser (LBMI; n=13). Each BMI group was divided into two sub-groups, which were either feed restricted (FR) or non-feed restricted (NFR). Goats in the NFR groups received a diet containing 100% of the daily maintenance requirements (basal diet), while restricted goats were subjected to alternated periods, receiving 100% (11d) and 60% (10d) of the basal diet, during the entire experimental period. The experiment started after does were treated to synchronize time of estrus. Serum progesterone was determined in samples obtained twice a week, and used as a criterion for determining ovulations. During the transition to the anovulatory period three transrectal ovarian ultrasonographic scans were performed in a sub-group of 12 goats (n=3 for each treatment combination). The diameter of the largest follicle (LFD) and the total number of antral follicles >or=2mm (TAF) were recorded. Ultrasonographic ovarian scans were performed at 21, 42 and 63 days after the beginning of the experiment, concurrently with the end of each feed restriction period. The variables of response associated with ovulation were not influenced by BMI or BMIxFI interaction. However, FI influenced length of anovulatory season, as the anovulatory period was 30d longer (P<0.05) in the FR group as compared with the NFR group. Independently of treatments, TAF and LFD decreased from the first to the third ultrasonographic ovarian scan (13.2, 10.8 and 4.4 follicles; 3.7, 2.7 and 2.3mm). Nevertheless, in PER 1 the number of TAF was greater (P<0.05) in the FR as compared with NFR group and the GBMI group had a larger LFD (P<0.05) as compared to the LBMI group. It is concluded, that temporal restriction in feed intake could affect the time of cessation and initiation of ovulations during the periods of transition to seasonal anestrus and return to estrous activity, and increase the length of the anovulatory period. In addition, ovarian follicular development during transition into the anovulatory period is differentially influenced by food intake and the status of body energy stores.

Efecto de la época de parición sobre la presentación de estros posparto en ovejas (Ovis aries) rambouillet / Effect of lambing season on postpartum estrous presentation in rambouillet ewes (Ovis aires)

El presente estudio se realizó con el objetivo de evaluar la presentación de estros dentro de los 100 días posparto en ovejas Rambouillet paridas en tres épocas del año mantenidas en condiciones de confinamiento y alimentación controlada. El trabajo se realizó en San Luis Potosí, México (21° 50’ LN) con 158 ovejas adultas de la raza Rambouillet paridas en tres épocas del año: julio (n=39), noviembre (n=79) y abril (n=40). Para detectar a las ovejas en estro, en cada periodo se utilizó una hembras androgenizada con 250 mg de enantato de testosterona. El periodo de observación comprendió del día 25 al día 100 de iniciadas las pariciones. Las proporción de ovejas en celo difirió entre épocas de parición (P<0,001), siendo de 28/39 (71,8 por ciento), 32/79 (40,5por ciento) y 4/40 (10,0 por ciento) en las pariciones de julio, noviembre y abril, respectivamente. El intervalo parto primer estro fue similar en las ovejas que mostraron estro dentro de los 100 días posparto en los tres periodos (54,4 ± 18,3, 54,4 ± 22,2 y 56,2 ± 21,6 días, en julio, noviembre y abril, respectivamente; P>0,05). Se concluye que la época de parición influyó en la actividad estral de las ovejas Rambouillet dentro de los 100 días posparto.

Postpartum estrus of Rambouillet ewes lambed on three seasons under confinement conditions and controlled feeding was evaluated. The experiment was carried out on San Luis Potosí, México (21° 50’ NL) with 158 Rambouillet adult ewes lambed in three seasons: July (n=39), November (n=79) and April (n=40). To detection of ewes showing estrus within 100 day from lambing, an androgenized ewe were used in each period (250 mg testosterone). The period of estrus observation started at the day 25 from lambing, and finished at the day 100. The proportion of ewes showing estrus were 28/39 (71.8%), 32/79 (40.5%) y 4/40 (10.0%) in July, November and April, respectively, and were different (P<0.001) between lambing seasons. The period between lambing and first estrus in the ewes showing estrus were similar in both three lambing periods (54.4 ± 18.3, 54.4 ± 22.2 and 56.2 ± 21.6 days, in July, November and April, respectively; P>0.05). Results indicate that the lambing season had a profound effect on sexual activity in Rambouillet ewes within 100 days postpartum period.

Efectos de la inclusión de un concentrado de proteína de soya y dos fuentes de energía en el substituto de leche en el comportamiento productivo de cabritos nubios / Effect of a soy protein concetrate and two energy sources as milk substitutes on productive performance nubian kids

El objetivo de este trabajo fue evaluar la inclusión de un concentrado de proteína de soya y dos fuentes de energía en el substituto de leche sobre el comportamiento productivo de cabritos Nubios desde el nacimiento hasta el destete, manejados en la Unidad Caprina de la Facultad de Agronomía, Universidad Autónoma de San Luis Potosí, México. Se utilizaron sesenta y ocho cabritos (35 hembras y 33 machos) asignados de manera aleatoria a los tratamientos: T1: proteína láctea + sebo de res, T1: 20,0 por ciento de concentrado de proteína de soya + sebo de res, T1: 40,0 por ciento de concentrado de proteína de soya + sebo de res, T1: proteína láctea + sebo de puerco, T1: 20,0 por ciento de concentrado de proteína de soya + sebo de puerco y, T1: 40,0 por ciento de concentrado de proteína de soya + sebo de puerco. El concentrado de proteína de soya no afectó (P>0,05) el consumo de dieta líquida ni la ganancia diaria de peso promedio, pero afectó significativamente (P<0,05) el consumo de concentrado de iniciación (95;95 y 97 g d-¹ animal-¹). Las fuentes de energía no afectaron (P>0,05) el consumo de la dieta líquida ni la ganancia diaria de peso promedio, pero afectaron (P<0,05) el consumo de concentrado de iniciación (97 vs 95 g d-¹ animal-¹). El sexo de los cabritosno afectó (P>0,05) el consumo del substituto de leche ni la ganancia diaria de peso promedio, pero si afectó (P<0,05) el consumo de concentrado de iniciación (100 vs. 92 g d-1animal-1para machos y hembras, respectivamente). El periodo experimental (semanas) afectó significativamente (P<0,05) todas las variables. Los niveles de concentrado de proteína de soya, fuentes de energía y sexo de la cría no afectaron (P>0,05) la conversión de alimento en base a sólidos totales de la leche. Se presentaron algunas interacciones significativas (P<0,05) en el consumo de substituto de leche y concentrado de iniciación.

The objective of this work was to evaluate the inclusion of a concentrate of soy protein and two energy sources as milk substitutes on productive performance of Nubian kids from birth to weaning, managed at the Goat Unit of the Faculty of Agronomy, Universidad Autónoma de San Luis Potosí, México. Sixty eight kids (35 females and 33 males) were randomly assigned to the treatments: T1 : lactic protein + cow lard, T2 : 20.0% of concentrate of soy protein + cow lard, T3 : 40.0% of concentrate of soy protein + cow lard, T4 : lactic protein + pork lard, T5 : 20.0% concentrate of soy protein + pork lard and, T6 : 40.0% of concentrate of soy protein + pork lard. The concentrate of soy protein did not affect (P>0.05) neither the consumption of liquid diet nor average daily weight gain, but it affected (P<0.05) consumption of the starting concentrate (95; 95, and 97 g d-¹ animal-¹). The energy sources did not affect (P>0.05) neither consumption of the liquid diet nor average daily weight gain, but they affected (P<0.05) consumption of the starting concentrate (97 vs 95 g d-¹ animal-¹). Sex of kid did not affect (P>0.05) neither consumption of the milk substitute nor average daily weight gain, but it affected (P<0.05) consumption of the starting concentrate (100 vs 92 g d-¹ animal-¹ for males and females, respectively). The experimental period (weeks) affected (P<0.05) all variables. The levels of the concentrate of soy protein, energy sources, and sex of kids did not affect (P>0.05) feed conversion based on milk total solids. There were some significant interactions (P<0.05) on consumption of the milk substitute and starting concentrate. It is concluded that it is possible to raise kids with milk substitutes prepared with a concentrate of soy protein, cow and/or pork lard.