Physiological responses of Bos taurus and Bos indicus cattle to prolonged, continuous heat and humidity

Two experiments were conducted to investigate the physiological responses of Bos taurus (Angus cross, n = 6) and Bos indicus (Brahman, n = 6) cattle to prolonged heat and humidity, as can occur during live export by sea. Each experiment was carried out in climate-controlled rooms, where heifers were exposed to 15 d of sustained heat and humidity. The treatment was designed to be representative of a long-haul, live-export voyage leaving a southern Australian winter and traveling to a Middle Eastern summer. Wet bulb temperature (WBT) was used to give a combined measure of dry bulb temperature and relative humidity and was increased over several days, culminating in 5 d at 32 degrees C WBT between d 7 and 11. By d 11, the respiratory rate and core body temperature increased (P < 0.001) compared with values at lower ambient temperature on d 1 and 2 when climate-controlled rooms were not operating. Feed intake of Bos taurus was reduced (P < 0.001) by d 11, whereas that of Bos indicus did not change (P = 0.14). Despite no diurnal variation in climatic conditions, core body temperature of both Bos taurus and Bos indicus continued to show a circadian amplitude of approximately 1 degrees C throughout the hottest period. This amplitude increased during the recovery period after heat was removed (up to 1.8 degrees C for Bos indicus and 1.6 degrees C for Bos taurus). Water intake for both Bos taurus and Bos indicus increased when WBT increased (P < 0.01 on d 11). Significant acid-base and blood electrolyte imbalances occurred in both Bos taurus and Bos indicus, with changes in Bos taurus being more substantial and prolonged. The increase in respiratory rate coincided with a decrease in the partial pressures of carbon dioxide and bicarbonate in venous blood. However, during the hottest period, average daily venous blood pH remained unchanged. When the heat load was reduced after d 11, the blood pH decreased, indicating metabolic acidosis. Blood pH declined from 7.44 to 7.36 for Bos taurus (P < 0.001) and from 7.44 to 7.38 for Bos indicus (P < 0.001). Other parameters measured include heart rate; packed cell volume; plasma and urine Na, K, and Cl; urine pH; and specific gravity. Our results suggest that Bos taurus cattle experience significant physiological changes during exposure to prolonged and continuous high heat and humidity, with alterations persisting for some days after the heat-stress conditions subside. Bos indicus experience similar but less pronounced physiological changes.     

In vivo comparison of susceptibility between Bos indicus and Bos taurus cattle types to Theileria parva infection

The objective of this study was to determine whether Bos taurus cattle differ form Bos indicus in their susceptibility to infection with the Muguga stabilate of Theileria parva and in their resistance to the resultant disease. Ten Friesians (B. taurus), ten improved Borans (B. indicus), ten unimproved Borans (B. indicus) and ten Zebus (B. indicus) born to dams from an East Coast fever (ECF) endemic area were inoculated with an infective dose50 dilution of T. parva Muguga stabilate 147. All the animals except one Friesian and one Zebu developed schizont parasitosis. All the improved Borans, nine of the Friesians, eight of the unimproved Borans and six of the Zebus developed a febrile response. Four of the improved Borans, four of the Friesians and three of the unimproved Borans died of theileriosis. No significant difference (P > 0.05) in the prepatent period occurred between the groups, but the Zebus had a significantly shorter duration of schizont parasitosis (P > 0.05) and took a significantly shorter time to recover (P > 0.05) than the other three groups. There was no significant difference in the two parameters between the other three groups. The study showed that three B. indicus breds and a B. taurus breed are equally susceptible to T. parva infection. However, Zebus born to dams from an ECF endemic area showed a better ability to control the course of disease than cattle from ECF free areas.     

Comparative Histology of the Kidney of Bos taurus and Bos indicus Cattle

Twenty-six kidneys of 2–4 years old Bos indicus (zebu cattle) and twenty kidneys of 4-year old Bos taurus were examined under the light microscope. The renal tubular epithelial heights and diameters were smaller in zebu than in Bos taurus. The Bos indicus kidney had fewer vascular bundles in the outer medullary zone and a smaller number of capillaries per vascular bundle, hence a lower renal blood flow than in Bos taurus. The Bos indicus proximal tubules had broader brush borders than those of Bos taurus. The smaller renal corpuscles with smaller glomerular filtration surface and low renal blood flow are responsible for low glomerular filtration rate and urinary flow, enabling their kidneys to retain more water than those of Bos taurus.     

Composition and yield of milk from beef-type Bos taurus and Bos indicus X Bos taurus dams

Yield, butterfat, protein, lactose and solids-not-fat of milk from mature dams (n = 128) representing eight Bos taurus and Bos indicus X Bos taurus breed types were evaluated approximately 60, 105 and 150 d postpartum. Breed type was a significant source of variation in milk yield at each stage of lactation. Average 24-h milk yields (kg) were: Hereford, 7.3; Red Poll, 9.1; Hereford X Red Poll, 9.1; Red Poll X Hereford, 9.1; Angus X Hereford, 8.6; Angus X Charolais, 9.3; Brahman X Hereford, 7.3 and Brahman X Angus, 8.3. Daily yields of Brahman X Angus dams increased as lactation progressed, while production levels of other breed types remained approximately the same or declined. Hereford-Red Poll crosses showed significant heterosis in 24-h milk production and component yields at 150 d. Breed type effects also were significant for lactose yield throughout lactation. Sex of calf influenced (P less than .05) milk yield at 60 and 105 d postpartum and yield of protein and solids-not-fat at 105 d. Mastitis caused a reduction (P less than .01) in percentage of lactose but had no effect on milk yield. Residual correlations between yield traits and preweaning average daily gain were all positive and significant, with values ranging from .22 to .45. Breed type was a major source of variation in milk traits of beef-type Bos taurus and Bos indicus X Bos taurus dams.     

Cow/calf preweaning efficiency of Nellore and Bos taurus x Bos indicus crosses

The objectives of this study were to determine if percentage Bos taurus (0 or 50%) of the cow had an effect on ME requirements and milk production, and to compare cow/calf efficiency among 3 mating systems. Metabolizable energy requirements were estimated during a feeding trial that encompassed a gestation and lactation feeding trial for each of 2 groups of cows. Cows were 0 or 50% Bos taurus (100 or 50% Nellore) breed type: Nellore cows (NL; n = 10) mated to Nellore bulls, NL cows (n = 9) mated to Angus bulls, Angus x Nellore (ANL; n = 10) and Simmental x Nellore (SNL; n = 10) cows mated to Canchim (5/8 Charolais 3/8 Zebu) bulls. Cows were individually fed a total mixed diet that contained 11.3% CP and 2.23 Mcal of ME/kg of DM. At 14-d intervals, cows and calves were weighed and the amount of DM was adjusted to keep shrunk BW and BCS of cows constant. Beginning at 38 d of age, corn silage was available to calves ad libitum. Milk production at 42, 98, 126, and 180 d postpartum was measured using the weigh-suckle-weigh technique. At 190 d of age, calves were slaughtered and body composition estimated using 9-10-11th-rib section to obtain energy deposition. Regression of BW change on daily ME intake (MEI) was used to estimate MEI at zero BW change. Increase in percentage Bos taurus had a significant effect on daily ME requirements (Mcal/d) during pregnancy (P < 0.01) and lactation (P < 0.01). Percentage Bos taurus had a positive linear effect on maintenance requirements of pregnant (P = 0.07) and lactating (P < 0.01) cows; during pregnancy, the ME requirements were 91 and 86% of those in lactation (131 +/- 3.5 vs. 145 +/- 3.4 Mcal x kg(-0.75) x d(-1)) for the 0 and 50% B. taurus groups, respectively. The 50% B. taurus cows, ANL and SNL, suckling crossbred calves had greater total MEI (4,319 +/- 61 Mcal; P < 0.01) than 0% B. taurus cows suckling NL (3,484 +/- 86 Mcal) or ANL calves (3,600 +/- 91 Mcal). The 0% B. taurus cows suckling ANL calves were more efficient (45.3 +/- 1.6 g/Mcal; P = 0.03) than straightbred NL (35.1 +/- 1.5 g/Mcal) and ANL or SNL pairs (41.0 +/- 1.0 g/Mcal). Under the conditions of this study, crossbreeding improved cow/ calf efficiency and showed an advantage for cows that have lower energy requirements.     

Susceptibility of Bos indicus and Bos taurus to Anaplasma marginale and Babesia bigemina infections

The reaction of Bos taurus and pure-bred Bos indicus heifers to infection with the intraerythrocytic parasites Anaplasma marginale and Babesia bigemina was studied. B. bigemina infection at 18 months and A. marginale infection at 13 or 24 months resulted in slightly less severe reactions in pure-bred Bos indicus cattle than in Bos taurus. In both breeds, the reaction to A. marginale infection was more severe in older cattle. The severity of B. bigemina infection was not affected by a previous infection with A. marginale.     

Comparative Thickness of the Medulla of Bos taurus and Bos indicus Kidneys

Twenty kidneys of 4 years old Bos taurus cattle and 26 kidneys of 2—4 years old Bos indicus (Zebu cattle) of East African Shorthorn breen were examined lobe by lobe after fixation. The cortex and medulla with subunits were measured and compared in the two sub-species. The width of the cortex was about the same in both. The outer and inner stripes of the outer medullary zone were significantly broader in Bos taurus whereas outer inner zone was significantly broader in Bos indicus. The width of the entire medulla was greater in Bos taurus.     

Induction of ovulation with GnRH and PGF2alpha in lactating Bos taurus x Bos indicus cows

Induction of ovulation for timed artificial insemination (TAI) with the Ovsynch protocol was evaluated in 49 anoestrous and lactating Bos taurus x Bos indicus cows. Palpation per rectum and transrectal ultrasonography were used on Days -30, -20, -10 and 0 (start of treatment) to confirm anoestrus but with the presence of follicles > or = 10 mm, and every other day during treatment to determine ovarian activity. Cows were randomly assigned to: (1) Ovsynch (n = 24; Day 0, 200 microg GnRH; Day 7, 150 microg PGF2alpha; Day 9, 200 microg GnRH + TAI 16 to 20 h later) and (2) control (n = 25; no treatment). Rates of ovulation for the first GnRH injection, detection of a corpus luteum (CL) at PGF2alpha injection, pregnancy and induction of cyclicity were greater (P < 0.05) with Ovsynch. There was no effect of body condition score (P > 0.05). In conclusion, the Ovsynch protocol was not effective in obtaining acceptable pregnancy rate for TAI, but it was effective for induction of cyclicity in anoestrous and lactating Bos taurus x Bos indicus cows under tropical conditions.     

Bos taurus Y chromosome of Africander cattle and the development of improved breeds for the tropics.

The Africander has anatomical and other characteristics of an animal of approximately 3/4 Bos indicus heredity. The fact that these cattle carry the Bos taurus Y chromosome supports this view and indicates that the local cattle in South Africa would have been crossed with one or more Bos taurus bulls. Droughtmaster and Braford cattle retain the Bos indicus Y chromosome because Bos indicus instead of Bos taurus bulls were used to establish these taurindicus breeds. Contrary to some assumptions, an approximate tenfold increase in productivity of cattle was made during the 18th and 19th centuries due to improvements in disease control, nutrition and genetic improvement. What is now needed is the development of taurindicus breeds combining to the maximum possible extent the disease resistance and hardiness of Bos indicus with the early maturity and productivity of Bos taurus cattle. In addition, the ravages of disease and the seasonal variations of food supply need to be overcome in tropical areas.     

性别和营养水平对福建河田鸡风味前体物质含量的影响

研究了不同性别和日粮能量、蛋白水平对河田鸡胸肌肉中风味前体化合物含量的影响。结果表明：性别对腹脂率、氨基酸（Asp、Thr、Ser、Pro、Cys除外）以及肌内脂肪（IMF）及其饱和脂肪酸（SFA）、单不饱和脂肪酸（MUFA）、多不饱和脂肪酸（PUFA）含量有显著影响（P〈0．05），而对肌苷酸（IMP）含量无显著影响（P〉0．05）；公鸡的总氨基酸（TAA）、肌苷酸、肌内脂肪中的SFA、MUFA含量略高于母鸡，母鸡的肌内脂肪及其PUFA含量明显高于公鸡。能量水平对肌苷酸、肌内脂肪及其SFA、MUFA、PUFA以及总氨基酸含量有显著影响（P〈0．05）；当鸡采食高能日粮时，肌内脂肪中的SFA、MUFA含量会显著升高（P〈0．05），而IMP、IMF、PUFA含量会显著下降（P＜0．05），TAA没有显著变化。蛋白水平对肌内脂肪及其MUFA、PUFA含量以及总氨基酸含量有显著影响（P〈0．05）。当采食高蛋白日粮时，肌内脂肪及SFA、MUFA显著降低，而其PUFA会显著增加（P〈0．05）。风味品尝结果表明，公鸡的香味、鲜味都显著高于母鸡，而嫩度低于母鸡；随着能量和蛋白水平的增加，鲜味和嫩度都显著下降（P〈0．05）。从肉品的总可接受性来看，性别对总可接受性没有显著影响（P〉0．05），低营养水平时的总可接受性大于高营养水平（P〈0．05）。     

Genetic analysis of beef fatty acid composition predicted by near-infrared spectroscopy

The aims of this study were 1) to investigate the potential application of near-infrared spectroscopy (NIRS) to predict intramuscular fat (IMF) and fatty acid (FA) composition of individual meat samples, 2) to estimate heritability of IMF and FA NIRS-based predictions, and 3) to assess the statistical relevance of the genetic background of such predictions by using the Bayes factor (BF) procedure. Young Piemontese bulls (n = 1,298) were raised and fattened on 124 farms, and slaughtered at the same commercial abattoir. Intramuscular fat content and FA composition were analyzed on a random subset of 148 samples of minced and homogenized longissimus thoracis muscle. Near-infrared spectroscopy spectra were collected on all samples (n = 1,298) in reflectance mode between 1,100 and 2,498 nm (every 2 nm) using fresh minced meat samples. Calibration models developed from the random subset of 148 samples were used to predict IMF and FA contents of the remaining 1,150 samples. Intramuscular fat content and FA predictions were analyzed under a Bayesian univariate animal linear models, and the statistical relevance of heritability estimates was assessed through BF; the model with polygenic additive effects was favored when BF > 1. In general, satisfactory results (R(2) > 0.60) were obtained for 6 out of the 8 major FA (C14:0, C:16:0, C16:1, C18:0, C18:1n-9 cis/trans, and C18:1n-11 trans), 6 out of the 19 minor FA (C10:0, C12:0, C17:0, C17:1, C18:2 cis-9,trans-11, and C20:2), and the total SFA, MUFA, and PUFA. Bayes factors between models with and without a genetic component provided values greater than 1 for IMF, C14:0, C16:0, C18:1n-9 cis/trans, C17:0, C17:1, C20:2, SFA, MUFA, and PUFA. The greatest BF was reached by C20:2 (BF >10), suggesting strong evidence of genetic determinism, whereas IMF, C18:1n-9 cis/trans, C17:0, C17:1, MUFA, and PUFA showed substantial evidence favoring the numerator model (3.16 < BF < 10). Point estimates of heritabilities for FA predicted by NIRS were low to moderate (0.07 to 0.21). Results support that NIRS is a useful technique to satisfactorily predict some FA of meat. The existence of an important genetic determinism affecting FA profile has been confirmed, suggesting that FA composition of meat can be genetically modified.     

莱芜猪肌肉脂肪酸组成的发育性变化及其对肉质特性的影响

以40￣90kg6个体重阶段莱芜猪和新莱芜猪为试验对象(n=6),研究肌肉脂肪酸组成的发育性变化及其与肉质特性的关系。结果表明:①随着体重的增大,莱芜猪肌肉总脂含量显著(P<0.01)增加;饱和脂肪酸(SFA)总量的比例有下降的趋势,不饱和脂肪酸(UFA)总量有增加的趋势,但差异不显著;在UFA中,多不饱和脂肪酸(PUFA)总量及亚油酸的比例显著(P<0.01)下降,油酸比例显著(P<0.01)增加;②总体上,莱芜猪肌肉中的SFA+单不饱和脂肪酸总量、总脂、棕榈酸、棕榈烯酸的比例显著高于新莱芜猪,而PUFA总量、硬脂酸、亚油酸、花生烯酸的比例显著(P<0.01)低于新莱芜猪。各体重阶段2个品种间的脂肪酸组成也存在着较大的差异;③莱芜猪肌肉中的PUFA总量与总脂、水分、失水率、大理石纹评分相关显著;总脂与水分、大理石纹相关极显著(P<0.01);SFA、UFA总量与大理石纹呈显著(P<0.05)相关。     

A new single nucleotide polymorphism in CAPN1 extends the current tenderness marker test to include cattle of Bos indicus, Bos taurus, and crossbred descent

The three objectives of this study were to 1) test for the existence of beef tenderness markers in the CAPN1 gene segregating in Brahman cattle; 2) test existing CAPN1 tenderness markers in indicus-influenced crossbred cattle; and 3) produce a revised marker system for use in cattle of all subspecies backgrounds. Previously, two SNP in the CAPN1 gene have been described that could be used to guide selection in Bos taurus cattle (designated Markers 316 and 530), but neither marker segregates at high frequency in Brahman cattle. In this study, we examined three additional SNP in CAPN1 to determine whether variation in this gene could be associated with tenderness in a large, multisire American Brahman population. One marker (termed 4751) was associated with shear force on postmortem d 7 (P < 0.01), 14 (P = 0.015), and 21 (P < 0.001) in this population, demonstrating that genetic variation important for tenderness segregates in Bos indicus cattle at or near CAPN1. Marker 4751 also was associated with shear force (P < 0.01) in the same large, multisire population of cattle of strictly Bos taurus descent that was used to develop the previously reported SNP (referred to as the Germplasm Evaluation [GPE] Cycle 7 population), indicating the possibility that one marker could have wide applicability in cattle of all subspecies backgrounds. To test this hypothesis, Marker 4751 was tested in a third large, multisire cattle population of crossbred subspecies descent (including sire breeds of Brangus, Beefmaster, Bonsmara, Romosinuano, Hereford, and Angus referred to as the GPE Cycle 8 population). The highly significant association of Marker 4751 with shear force in this population (P < 0.001) confirms the usefulness of Marker 4751 in cattle of all subspecies backgrounds, including Bos taurus, Bos indicus, and crossbred descent. This wide applicability adds substantial value over previously released Markers 316 and 530. However, Marker 316, which had previously been shown to be associated with tenderness in the GPE Cycle 7 population, also was highly associated with shear force in the GPE Cycle 8 animals (P < 0.001). Thus, Marker 316 may continue to be useful in a variety of populations with a high percentage of Bos taurus backgrounds. An optimal marker strategy for CAPN1 in many cases will be to use both Markers 316 and 4751.     

Spermatogenesis in Bali cattle (Bos sondaicus) and hybrids with Bos indicus and Bos taurus

Semen quality, testis size and efficiency of sperm production in Bali cattle (Bos sondaicus) and hybrids with Bos indicus and Bos taurus were determined. Mean (+/- SEM) daily sperm production per gram of testis parenchyma (DSPG) in six purebred Bali bulls was 12.2 +/- 0.7 x 10(6). F1 B sondaicus cross B taurus bulls and F1 B sondaicus cross B indicus bulls were sterile. Spermatogenesis was arrested at the late primary spermatocyte stage. In 11 B sondaicus cross B indicus crosses, mean DSPG was lower than in the purebred B sondaicus, although four (one 1/4 B sondaicus, one 3/4 B sondaicus, one 5/8 B sondaicus inter se and one 3/8 B sondaicus inter se) exhibited DSPG levels similar to the foundation stock. Semen from those crossbreeds which exhibited complete spermatogenesis was more variable in terms of spermatozoal concentration, percentage of spermatozoa exhibiting progressive motility and levels of spermatozoal abnormalities. In crossbreeds where sperm production was reduced or absent, there was seminiferous epithelial dysfunction, manifested as an increased frequency of degenerative late pachytene and diplotene primary spermatocytes and germinal cells occurring later in the cycle, or in extreme cases, as complete arrest of spermatogenesis at the late primary spermatocyte stage.     

中国黄牛Y-STRs遗传多样性与起源研究

[目的]研究中国黄牛Y染色体STRs的遗传多样性及父系起源。[方法]利用非变性聚丙烯酰胺凝胶电泳,选择2个牛Y-STRs位点INRA189和BM861,分析16个中国地方黄牛品种284头公牛与4头缅甸黄牛公牛的Y染色体遗传多样性。[结果]在中国16个黄牛品种中,2个Y-STR位点可以区分中国黄牛中的普通牛和瘤牛类型,表明中国黄牛有普通牛和瘤牛两种父系起源。4头缅甸黄牛均为瘤牛类型。在中国16个黄牛品种中,普通牛和瘤牛分布频率分别为57.0%和43.0%,其中普通牛频率在北方黄牛中占优势(98.3%),瘤牛频率在南方黄牛中占优势(76.1%),中原黄牛中普通牛频率较高为63.8%,瘤牛频率为36.2%。[结论]中国黄牛存在普通牛和瘤牛两种父系起源;普通牛频率自北向南逐渐减少,瘤牛频率自北向南逐渐增加,中原地区为普通牛和瘤牛的交汇处。     

Synchronization of Bos indicus x Bos taurus cows for timed artificial insemination using gonadotropin-releasing hormone plus prostaglandin F2alpha in combination with melengestrol acetate

Nonlactating Bos indicus x Bos taurus cows were used in three herds to determine the efficacy of different PGF2alpha treatments in combination with GnRH and melengestrol acetate (MGA) for a timed artificial insemination protocol. The start of the experiment was designated as d 0, at which time cows were assigned a body condition score and received 100 microg of GnRH. Cows were fed MGA (0.5 x mg x cow(-1) x d(-1)) on d 1 to 7. On d 7, cows received either a single injection of PGF2alpha (Lutalyse sterile solution; 25 mg; n = 297), a single injection of cloprostenol sodium (Estrumate; 500 microg; n = 297), or half the recommended dose of PGF2alpha (12.5 mg; n = 275) on d 7 and 8. On d 10, all cows were artificially inseminated and received 100 microg of GnRH. Pregnancy rates to the timed artificial insemination (39%) were not affected by treatment, herd, or treatment x herd. There was an effect (P < 0.01) of artificial insemination sire on timed artificial insemination pregnancy rate for one herd, but not the other two herds. Herd influenced (P < 0.05) 30-d pregnancy rates, but there were no treatment or treatment x herd effects as 72.3% of the cows became pregnant during the first 30 d of the breeding season. Results indicate that the type of PGF2alpha treatment administered 7 d after GnRH did not influence timed artificial insemination pregnancy rates in nonlactating Bos indicus x Bos taurus cows.     

The Issue of Carcass Tenderness Expressed by Cattle Varying in Bos indicus Inheritance

This review reveals that relative to Bos taurus cattle, cattle varying in Bos indicus inheritance, especially cattle that are > 1/2 Bos indicus inheritance, lack carcass tenderness. Because consumers are willing to pay for more tender beef, it seems imperative that the commercial beef cattle industry should refrain from producing cattle that are > 1/2 Bos indicus inheritance. Because of their Superior preweaning maternal performance, F₁Bos indicus ♂ × Bos taurus 9 females and their resulting contemporary F₁steer mates will continue to be produced by the commercial beef cattle industry in the Southeast and Golf Coast areas of the U.S. Further, as progeny testing for tenderness is expensive, it is suggested that the F₁Bos indicus ♂ x Bos taurus 9 steers be identified by the commercial beef cattle industry so that the packing/ retail industries can utilize existing postmortem technology (electrical stimulation, blade tenderization, extended aging, calcium chloride injections) to partially alleviate the lack of tenderness expressed by carcasses resulting from these cattle.     

南阳黑猪和大白猪脂肪酸分析及其综合评价

试验旨在研究南阳黑猪脂肪酸组成及含量,以期为中国地方猪种遗传资源的保护及开发利用提供理论依据。以南阳黑猪和大白猪为研究对象,每品种猪各12头,测量背最长肌脂肪酸含量及种类,以脂肪酸种类及数量、单不饱和脂肪酸（monounsaturated fatty acid,MUFA）、多不饱和脂肪酸（polyunsaturated fatty acid,PUFA）、饱和脂肪酸（saturated fatty acid,SFA）、12-16碳饱和脂肪酸（饱和脂肪酸1,SFA1）、其他饱和脂肪酸（饱和脂肪酸2,SFA2）、不饱和脂肪酸（unsaturated fatty acids,UFA）、SFA2/SFA1、PUFA/MUFA、必需脂肪酸（essential fatty acid,EFA）、共轭亚油酸（conjugated linoleic acids,CLA）、PUFA/SFA、ω-6 PUFA/ω-3 PUFA等为指标,从营养、健康、风味及储存方面综合评价两个猪种猪肉脂肪酸品质。结果显示,两个猪种背最长肌中共检出30种脂肪酸,其中23种脂肪酸在两个猪种间有显著或极显著差异（P<0.05;P<0.01）;除SFA2/SFA1和ω-6 PUFA /ω-3 PUFA外,南阳黑猪其他指标均高于大白猪;SFA1、MUFA、PUFA、SFA、UFA、UFA/SFA、SFA2/SFA1、PUFA/MUFA、EFA、CLA、PUFA/SFA、ω-6 PUFA/ω-3 PUFA 11个指标在两个猪种间存在显著或极显著差异（P<0.05;P<0.01）,SFA2和PUFA/MUFA在两个猪种间无显著差异（P>0.05）。综合以上结果,南阳黑猪肌肉脂肪酸品质总体优于大白猪。     

The Effect of Season on Semen Characteristics and Freezability in Bos indicus and Bos taurus Bulls in the Southeastern Region of Brazil

The objectives of this study were to evaluate the effects of season in southeast of Brazil comparing genotypes on semen characteristics, freezability and peripheral plasma concentrations of testosterone. Ejaculates of five Bos indicus bulls and six Bos taurus bulls were evaluated over a period of 27 months, which was divided into winter (July, August, September), spring (October, November, December), summer (January, February, March) and autumn (April, May, June). Semen was evaluated according to standard procedures for ejaculate volume, sperm concentration, gross-motility, progressive motility and sperm morphology. After preparing and freezing the ejaculates according to commercial procedures, the straws were stored in liquid N₂ until post-thaw evaluation. Ejaculate volume, sperm concentration, gross-motility, progressive sperm motility, vigor and morphological sperm defects were significantly influenced by season and genotype (p < 0.05). Heat tolerance was better in B. indicus bulls than in B. taurus bulls characterized by lower values of sperm abnormalities throughout the observation period. The highest values were recorded for abnormal heads followed by cytoplasmatic droplets in B. taurus bulls. The proportion of ejaculates which were eliminated before freezing for reasons of bad quality was lower in the B. indicus bulls. Temporal changes in peripheral plasma testosterone concentrations were higher in B. indicus bulls than in B. taurus bulls not revealing seasonal influences. The results of this study show clear genotype differences regarding semen quality. Freezability of B. taurus semen varies considerably throughout the year, leading to a high proportion of eliminated ejaculates. Collecting semen from B. taurus bulls during the summer in an artificial insemination centre may not be profitable.     

Analysis and Comprehensive Evaluation of Fatty Acid in Nanyang Black Pig and Large White Pig

The experiment was carried out to study the composition and contents of fatty acids of Nanyang Black pig, and to provide a theoretical basis for the protection and exploitation of local pig genetic resources in China. 12 Nanyang Black pigs and 12 Large White pigs were chosen, and the composition and contents of fatty acids in longissimus dorsi muscle were measured, and the quality of fatty acids was comprehensive evaluated from nutrition, health, flavor and storage aspects. Monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA), 12-16 carbon saturated fatty acids (SFA1), other saturated fatty acids (SFA2), unsaturated fatty acids (UFA), saturated fatty acids (SFA), SFA2/SFA1, MUFA/PUFA, essential fatty acid (EFA), conjugated linoleic acids (CLA), PUFA/SFA and ω-6 PUFA/ω-3 PUFA were used as the indexes of multiple comparison. The results showed that there were 30 kinds of fatty acids were detected and 23 of them had significant or extremely significant differences between the two pig breeds (P<0.05;P<0.01). Nanyang Black pig had higher values of above measured indexes than that of Large White pig in addition to SFA2/SFA1 and ω-6 PUFA/ω-3 PUFA. 11 indexes such as SFA1,MUFA,PUFA,SFA,UFA, UFA/SFA,SFA2/SFA1,PUFA/MUFA, EFA,CLA, PUFA/SFA and ω-6 PUFA/ω-3 PUFA differed significantly or extremely significantly between the two pig breeds (P<0.05;P<0.01), while SFA2 and PUFA/MUFA had no significant differences between the two pig breeds (P>0.05). In conclusion, the fatty acids of Nanyang Black pig were significantly better than that of Large White pig.